Acoustic Studies
No shallow talk: deep social communication of Blainville´s beaked whales. Aguilar Soto, N., et al. (2011).
Cultural revolutions reduce complexity in the songs of humpback whales. Allen, Jenny A., et al. (2018).
Echolocation signals of free-ranging killer whales (Orcinus orca) and modeling of foraging for chinook salmon (Oncorhynchus tshawytscha). Au, W. W. L., et al. (2004).
Differences in acoustic signals from Delphinids in the western North Atlantic and northern Gulf of Mexico. Baron, Susan C., et al (2008).
Decades-long social memory in bottlenose dolphins. Bruck, Jason N.
Noise Levels of Multi-Rotor Unmanned Aerial Vehicles with Implications for Potential Underwater Impacts on Marine Mammals. Christiansen, Frederic., et al. (2016).
Noise exposure from commercial shipping for the southern resident killer whale population. Cominellia, Simone, et al. (2018).
Evidence for vocal learning in juvenile male killer whales, Orcinus orca, from an adventitious cross-socializing experiment. Crance, Jessica L., et al. (2014).
The structure of stereotyped calls reflects kinship and social affiliation in resident killer whales (Orcinus orca). Deecke, V.B., et al. (2010).
The vocal behaviour of mammal-eating killer whales: communicating with costly calls. Deecke, V. et al. (2005).
Selective habituation shapes acoustic predator recognition in harbor seals. Deecke, V.B., Ford (2002).
Dialect Change in Resident Killer Whales (Orcinus orca): Implications for Vocal Learning and Cultural Transmission. Deecke, V.B., Ford, J.K.B., P. Spong (2000).
Quantifying complex patterns of bioacoustic variation: Use of a neural network to compare killer whale (Orcinus orca) dialects. Deecke, V.B., J.K.B. Ford, P. Spong (1999).
Stability and Change of killer whale (Orcinus orca) dialects. Deecke, V.B. (1998).
Underwater noise of whale-watching boats and potential effects on killer whales (Orcinus orca) based on an acoustic impact model. Erbe, Christine (2002).
Sperm whale predator-prey interactions involve chasing and buzzing, but no acoustic stunning. Fais A., et al. (2016).
Evidence suggests vocal production learning in a cross-fostered Risso’s dolphin (Grampus griseus). Favaro L., et al. (2016).
Cultural evolution of killer whale calls: background, mechanisms and consequences. Filatova O.A., et al. (2015).
The structure of the discrete call repertoire of killer whales Orcinus orca from Southeast Kamchatka. Filatova O.A., et al. (2007).
Temporal and Contextual Patterns of Killer Whale (Orcinus orca) Call Type Production. Foote, A.D., et al. (2008).
Variation in call pitch among killer whale ecotypes. Foote, A.D. and Jeffrey A. Nystuen (2008).
Killer whales are capable of vocal learning. Foote, A.D. et al. (2006).
Correlates of variability in killer whale stereotyped call repertoires. Foote, A.D. (2005).
Whale-call response to masking boat noise. Foote, A.D. et al. (2004).
Vocal traditions among resident killer whales (Orcinus orca) in waters of British Columbia. Ford, J. K. B. (1991).
Family Fugues. Ford, J. K. B. (1991).
The dolphin's grammatical competency: Comments on Kako. Herman, L.M., R.K. Uyeyama (1999).
SETI meets a social intelligence: Dolphins as a model for real-time interaction and communication with a sentient species. Herzing, Denise (2010).
Speaking up: Killer whales (Orcinus orca) increase their call amplitude in response to vessel noise. Holt, Marla, et al (2008).
The Relationship between Vessel Traffic and Noise Levels Received by Killer Whales (Orcinus orca). Houghton, Juliana et al. (2015).
Study of Dolphin Communicational Behavior: Procedure, Motor and Acoustic Parameters. Ivanov, M.P. (2009).
Geographic variation in rates of vocal production of free-ranging bottlenose dolphins. Jones, Guenevere J. and Laela S. Sayigh (2002).
Vocal copying of individually distinctive signature whistles in bottlenose dolphins. King, Stephanie L., et al. (2013).
Dolphin echolocation behaviour during active long-range target approaches. Ladegaard, Michael, et al. (2019).
Using Static Acoustic Monitoring to Describe Echolocation Behaviour of Heaviside's Dolphins (Cephalorhynchus heavisidii) in Namibia. Leeney, Ruth H., et al. (2011).
Phylogenetic review of tonal sound production in whales in relation to sociality. May-Collado, Laura J. et al. (2007).
Toothed whales use distinct vocal registers for echolocation and communication. Madsen, Peter T. , Ursula Siebert, and Coen P. H. Elemans. (2023).
Passive acoustic methods applied to fin whale population density estimation. McDonald, M. A., C. G. Fox (1999).
Blue Whales Respond to Anthropogenic Noise. Melcón, Mariana L., et al. (2012).
A Comparison of Bottlenose Dolphin whistles in the Atlantic Ocean: Factors promoting whistle variation. May-Collado, Laura J. and Douglas Wartzok (2008).
Killer Whales and Herring: Using Sound to Get a Meal. Miller, Lee A., et al. (2006).
Diversity in sound pressure levels and estimated active space of resident killer whale vocalizations. Miller, P.J. (2006).
Within-pod variation in the sound production of a pod of killer whales, Orcinus orca. Miller, Patrick J. O., D. E. Bain, (2000).
Call-type matching in vocal exchanges of free-rangingresident killer whales, Orcinus orca. Miller, Patrick J. O., et al., (2001).
Mixed-directionality of killer whale stereotyped calls: a direction of movement cue? Miller, P.J.O. (2002).
Analysis of calls of killer whales (Orcinus orca) from Iceland and Norway. Moore, S. E.; et al. (1988).
Predation by killer whales (Orcinus orca) and the evolution of whistle loss and narrow-band high frequency clicks in odontocetes. Morisaka, T, R. C. Connor. (2007).
Sound and behavioral correlation in captive Orcinus orca. Morton, A. B., et al. (1986).
Acoustic monitoring of resident, offshore, and transient killer whales off the Washington coast. Oleson, Erin M., et al. (2006).
Consequences of global shipping traffic for marine giants. Pirotta, Vanessa, et al. (2018).
Cross-cultural and cross-ecotype production of a killer whale ‘excitement’ call suggests universality. Rehn, Nicola; et al. (2010).
Structural and temporal emission patterns of variable pulsed calls in free-ranging killer whales (Orcinus orca). Rehn, Nicola; et al. (2005).
Can Genetic Differences Explain Vocal Dialect Variation in Sperm Whales, Physeter macrocephalus? Rendell, L., et al. (2011).
Passive acoustic monitoring off Vancouver Island reveals extensive use by at-risk Resident killer whale (Orcinus orca) populations. Riera, A., et al. (2019).
Individual calling behaviour and movements of North Atlantic minke whales (Balaenoptera acutorostrata). Risch, D., Siebert, U. & Van Parijs, S.M. (2014).
Low-frequency signals produced by Northeast Atlantic killer whales (Orcinus orca). Samarra, Filipa I. P.; et al. (2016).
Killer whales (Orcinus orca) produce ultrasonic whistles. Samarra, Filipa I. P.; et al. (2010).
Vocal repertoire and acoustic behavior of the isolated AT1 killer whale subpopulation in southern Alaska. Saulitis, Eva L.; et al. (2007).
Individual recognition in wild bottlenose dolphins: a field test using playback experiments. Sayigh, L.S.; et al. (1998).
Call types of Bigg’s killer whales (Orcinus orca) in western Alaska: using vocal dialects to assess population structure. Sharpe, Deborah L. et al. (2017).
The relationship between the acoustic behaviour and surface activity of killer whales (Orcinus orca) that feed on herring (Clupea harengus). Simon, Malene; et al. (2007).
Icelandic killer whales (Orcinus orca) use a pulsed call suitable for manipulating the schooling behaviour of herring (Culpea harengus). Simon, Malene, et al. (2006).
Echolocation clicks from killer whales (Orcinus orca) feeding on herring (Clupea harengus). Simon, Malene, et al. (2007).
Stereotyped whistles in southern resident killer whales. Souhaut M, Shields MW. (2021).
Characteristics of whistles from the acoustic repertoire of resident killer whales (Orcinus orca) off Vancouver Island, British Columbia. Thomsen, F. Franck, D. and Ford, J.K.B. (2001).
Acoustic differentiation of Shiho- and Naisa-type short-finned pilot whales in the Pacific Ocean. Van Cise, A. et al. (2017).
Ship noise extends to frequencies used for echolocation by endangered killer whales. Veirs, Scott. et al. (2016).
Vocal Development in a Beluga Calf (Delphinapterus leucas). Valeria Vergara1 and Lance G. Barrett-Lennard (2008).
Vocal behavior of resident killer whale matrilines with newborn calves: The role of family signatures. Weiss, Brigitte M. et al. (2006).
Vocalisation of killer whales (Orcinus orca) in the Bremer Canyon, Western Australia. Wellard, R., et al. (2015).
Severity of killer whale behavioral responses to ship noise: A dose–response study. Williams, R., et al. (2014).
Vocal culture and social stability in resident killer whales (Orcinus orca). Yurk, Harald (2005).
Parallel cultural and genetic lineages in Alaskan resident type killer whales. Yurk, Harald (2001).
Cultural transmission within maternal lineages: vocal clans in resident killer whales in southern Alaska. Yurk, H., Barrett-Lennard, L., Ford, J.K.B., Matkin, C. (2002).
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Aguilar Soto, N., Johnson., M., Tyack., P., Arranz, P., Revelli, E., Marrero, J., Fais, A., Madsen, P. (2011). No shallow talk: deep social communication of Blainville´s beaked whales. Marine Mammal Science. DOI: 10.1111/j.1748-7692.2011.00495.x.
ABSTRACT
Communicating animals must balance fitness benefits against the costs of signaling, such as increased predation risk. Cetaceans communicate mainly with sound and near-surface vocalizations can place signalers at risk from shallow-diving top-predators with acute hearing such as killer whales. Beaked whales are deep-divers living in small cohesive groups with little social defense from predation and little if anything is known about their acoustic communication. Here eight Blainville’s beaked whales were studied with suction-cup attached DTAGs to provide the first report on social communication as a function of diving behavior for any of the 21 ziphiid species. Tagged whales produced two novel signals with apparent communicative functions: i) fast series of ultrasonic FM clicks (rasps) were recorded from six individuals, and ii) harmonically rich short whistles with a mean fundamental frequency of 12kHz were recorded from one whale at up to 900m depth, the deepest whistles recorded from a marine mammal. Blainville´s were silent 80% of the time, whenever shallower than 170m depth and during the prolonged (19min) silent ascents from vocal dives. This behavior limits the ability of shallow-diving predators to track Blainville´s acoustically, providing a striking example of the evolutionary influence of the risk of predation on animal communication.
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Allen, Jenny A., Ellen C. Garland, Rebecca A. Dunlop, Michael J. Noad (2018). Cultural revolutions reduce complexity in the songs of humpback whales. Proceedings of the Royal Society DOI: 10.1098/rspb.2018.2088.
ABSTRACT
Much evidence for non-human culture comes from vocally learned displays, such as the vocal dialects and song displays of birds and cetaceans. While many oscine birds use song complexity to assess male fitness, the role of complexity in humpback whale (Megaptera novaeangliae) song is uncertain owing to population-wide conformity to one song pattern. Although songs change gradually each year, the eastern Australian population also completely replaces their song every few years in cultural ‘revolutions’. Revolutions involve learning large amounts of novel material introduced from the Western Australian population. We examined two measures of song structure, complexity and entropy, in the eastern Australian population over 13 consecutive years. These measures aimed to identify the role of complexity and information content in the vocal learning processes of humpback whales. Complexity was quantified at two hierarchical levels: the entire sequence of individual sound ‘units’ and the stereotyped arrangements of units which comprise a ‘theme’. Complexity increased as songs evolved over time but decreased when revolutions occurred. No correlation between complexity and entropy estimates suggests that changes to complexity may represent embellishment to the song which could allow males to stand out amidst population-wide conformity. The consistent reduction in complexity during song revolutions suggests a potential limit to the social learning capacity of novel material in humpback whales.
Full paper HERE.
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Au, Whitlow W. L., John K. B. Ford, John K. Horne, Kelly A. Newman Allman (2004). Echolocation signals of free-ranging killer whales (Orcinus orca) and modeling of foraging for chinook salmon (Oncorhynchus tshawytscha). The Journal of the Acoustical Society of America -- February 2004 -- Volume 115, Issue 2, pp. 901-909.
ABSTRACT
Fish-eating "resident"-type killer whales (Orcinus orca) that frequent the coastal waters off northeastern Vancouver Island, Canada have a strong preference for chinook salmon (Oncorhynchus tshawytscha). The whales in this region often forage along steep cliffs that extend into the water, echolocating their prey. Echolocation signals of resident killer whales were measured with a four-hydrophone symmetrical star array and the signals were simultaneously digitized at a sample rate of 500 kHz using a lunch-box PC. A portable VCR recorded the images from an underwater camera located adjacent to the array center. Only signals emanating from close to the beam axis (1185 total) were chosen for a detailed analysis. Killer whales project very broadband echolocation signals (Q equal 0.9 to 1.4) that tend to have bimodal frequency structure. Ninety-seven percent of the signals had center frequencies between 45 and 80 kHz with bandwidths between 35 and 50 kHz. The peak-to-peak source level of the echolocation signals decreased as a function of the one-way transmission loss to the array. Source levels varied between 195 and 224 dB re:1 µPa. Using a model of target strength for chinook salmon, the echo levels from the echolocation signals are estimated for different horizontal ranges between a whale and a salmon. At a horizontal range of 100 m, the echo level should exceed an Orcinus hearing threshold at 50 kHz by over 29 dB and should be greater than sea state 4 noise by at least 9 dB. In moderately heavy rain conditions, the detection range will be reduced substantially and the echo level at a horizontal range of 40 m would be close to the level of the rain noise.
Baron, Susan C., Anthony Martinez, Lance P. Garrison, Edward O. Keith. (2008). Differences in acoustic signals from Delphinids in the western North Atlantic and northern Gulf of Mexico. Marine Mammal Science, Volume 24 Issue 1 Page 42-56, January 2008.
ABSTRACT
Whistle characteristics were quantitatively compared between both geographically separated and neighboring populations of Atlantic spotted dolphins (Stenella frontalis), bottlenose dolphins (Tursiops truncatus), and pilot whales (Globicephala spp.) in U.S. waters to evaluate if intraspecific acoustic differences exist between groups. We compared nine whistle characteristics between continental shelf and offshore Atlantic spotted dolphins in the western North Atlantic and between northern Gulf of Mexico and western North Atlantic bottlenose dolphins and pilot whales using discriminant analysis. Offshore Atlantic spotted dolphin whistles were significantly different (Hotelling's T2, P = 0.0003) from continental shelf whistles in high frequency, bandwidth, duration, number of steps, and number of inflection points. Atlantic bottlenose dolphin whistles were significantly different (Hotelling's T2, P less than 0.0001) from those in the Gulf of Mexico in duration, number of steps, and number of inflection points. There was no significant difference between pilot whale whistles in the two basins. The whistle differences indicate acoustic divergence between groups in different areas that may arise from geographic isolation or habitat separation between neighboring but genetically distinct populations of dolphins. This study supports the premise that acoustic differences can be a tool to evaluate the ecological separation between marine mammal groups in field studies.
Bruck, Jason N. Decades-long social memory in bottlenose dolphins. Proc. R. Soc. B 2013 280, 20131726, published 7 August 2013.
ABSTRACT
Long-term social memory is important, because it is an ecologically relevant test of cognitive capacity, it helps us understand which social relationships are remembered and it relates two seemingly disparate disciplines: cognition and sociality. For dolphins, long-term memory for conspecifics could help assess social threats as well as potential social or hunting alliances in a very fluid and complex fission–fusion social system, yet we have no idea how long dolphins can remember each other. Through a playback study conducted within a multi-institution dolphin breeding consortium (where animals are moved between different facilities), recognition of unfamiliar versus familiar signature whistles of former tank mates was assessed. This research shows that dolphins have the potential for lifelong memory for each other regardless of relatedness, sex or duration of association. This is, to my knowledge, the first study to show that social recognition can last for at least 20 years in a non-human species and the first large-scale study to address long-term memory in a cetacean. These results, paired with evidence from elephants and humans, provide suggestive evidence that sociality and cognition could be related, as a good memory is necessary in a fluid social system.
Full paper HERE.
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Cominelli, Simone, Rodolphe Devillers, Harald Yurk, Alexander MacGillivray, Lauren McWhinnie, Rosaline Canessa (2018). Noise exposure from commercial shipping for the southern resident killer whale population. Marine Pollution Bulletin 136 (2018) 177–200.
ABSTRACT
This study assesses vessel-noise exposure levels for Southern Resident Killer Whales (SRKW) in the Salish Sea. Kernel Density Estimation (KDE) was used to delineate SRKW summer core areas. Those areas were combined with the output of a regional cumulative noise model describing sound level variations generated by commercial vessels (1/3-octave-bands from 10 Hz to 63.1 kHz). Cumulative distribution functions were used to evaluate SRKW's noise exposure from 15 vessel categories over three zones located within the KDE. Median cumulative noise values were used to group categories based on the associated exposure levels. Ferries, Tugboats, Vehicle Carriers, Recreational Vessels, Containers, and Bulkers showed high levels of exposure (Leq-50th > 90 dB re 1 µPa) within SRKW core areas. Management actions aiming at reducing SRKW noise exposure during the summer should target the abovementioned categories and take into consideration the spatial distribution of their levels of exposure, their mechanical and their operational characteristics.
Full paper HERE.
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Christiansen, Fredrik, Laia Rojano-Doñate, Peter T. Madsen and Lars Bejder 2016. Noise Levels of Multi-Rotor Unmanned Aerial Vehicles with Implications for Potential Underwater Impacts on Marine Mammals. Front. Mar. Sci., 26 December 2016 | https://doi.org/10.3389/fmars.2016.00277.
ABSTRACT
Despite the rapid increase in the use of unmanned aerial vehicles (UAVs) in marine mammal research, knowledge of the effects of UAVs on study animals is very limited. We recorded the in-air and in-water noise from two commonly used multi-rotor UAVs, the SwellPro Splashdrone and the DJI Inspire 1 Pro, to assess the potential for negative noise effects of UAV use. The Splashdrone and Inspire UAVs produced broad-band in-air source levels of 80 dB re 20 µPa and 81 dB re 20 µPa (rms), with fundamental frequencies centered at 60 Hz and 150 Hz. The noise of the UAVs coupled poorly into the water, and could only be quantified above ackground noise of the recording sites at 1 m depth when flying at altitudes of 5 and 10 m, resulting in broad-band received levels around 95 dB re µPa rms for the Splashdrone and around 101 dB re µPa rms for the Inspire. The third octave levels of the underwater UAV noise profiles are (i) close to ambient noise levels in many shallow water habitats, (ii) largely below the hearing thresholds at low frequencies of toothed whales, but (iii) likely above the hearing thresholds of baleen whales and pinnipeds. So while UAV noise may be heard by some marine mammals underwater, it is implied that the underwater noise effect is small, even for animals close to the water surface. Our findings will be valuable for wildlife managers and regulators when issuing permits and setting guidelines for UAV operations. Further, our experimental setup can be used by others to evaluate noise effects of larger sized UAVs on marine mammals.
Full paper HERE.
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Crance, Jessica L., Ann E. Bowles, and Alan Garver 2014. Evidence for vocal learning in juvenile male killer whales, Orcinus orca, from an adventitious cross-socializing experiment. The Journal of Experimental Biology (2014) 217, 1229-1237 doi:10.1242/jeb.094300.
ABSTRACT
Killer whales (Orcinus orca) are thought to learn their vocal dialect. Dispersal in the species is rare, but effects of shifts in social association on the dialect can be studied under controlled conditions. Individual call repertoires and social association were measured in three adult female killer whales and three males (two juveniles and an adult) during two periods, 2001–2003 and 2005–2006. Three distinct dialect repertoires were represented among the subjects. An adventitious experiment in social change resulted from the birth of a calf and the transfer of two non-focal subjects in 2004. Across the two periods, 1691 calls were collected, categorized and attributed to individuals. Repertoire overlap for each subject dyad was compared with an index of association. During 2005–2006, the two juvenile males increased association with the unrelated adult male. By the end of the period, both had begun producing novel calls and call features characteristic of his repertoire. However, there was little or no reciprocal change and the adult females did not acquire his calls. Repertoire overlap and association were significantly correlated in the first period. In the second, median association time and repertoire similarity increased, but the relationship was only marginally significant. The results provided evidence that juvenile male killer whales are capable of learning new call types, possibly stimulated by a change in social association. The pattern of learning was consistent with a selective convergence of male repertoires.
Full paper HERE.
Deecke, Volker B., John K.B. Ford, and Peter J.B. Slater (2005). The vocal behaviour of mammal-eating killer whales: communicating with costly calls. Animal Behaviour Volume 69, Issue 2, February 2005, Pages 395-405.
ABSTRACT
The cost of vocal behaviour is usually expressed in energetic terms; however, many animals may pay additional costs when predators or potential prey eavesdrop on their vocal communication. The northeastern Pacific is home to two distinct ecotypes of killer whales, Orcinus orca, called residents and transients. Resident killer whales feed on fish, a prey with poor hearing abilities, whereas transient killer whales hunt marine mammals, which have sensitive underwater hearing within the frequency range of killer whale vocal communication. In this study, we investigated how the superior hearing ability of mammalian prey has shaped the vocal behaviour of the transient killer whale ecotype. We recorded pulsed calls and the associated behavioural context of groups of transient and resident killer whales in British Columbia and southeastern Alaska. Transient killer whales produced pulsed calls significantly less frequently than residents. Transient killer whales only showed significant amounts of vocal behaviour after a marine mammal kill or when the whales were displaying surface-active behaviour. Vocal activity of transients increased after a successful attack on a marine mammal. Since marine mammals are able to detect killer whale pulsed calls and respond with antipredator behaviour, the reduced vocal activity of transients is probably due to a greater cost for calling in this ecotype resulting from eavesdropping by potential prey. The increase in vocal behaviour after a successful attack may represent food calling (informing other animals in the area about the presence of food), but is more likely to reflect an increase in social interactions during feeding and/or the fact that the cost for vocal behaviour is comparatively low after a successful attack.
Deecke, V. B., Barrett-Lennard, L. G., Spong, P. & Ford, J. K. B. 2010. The structure of stereotyped calls reflects kinship and social affiliation in resident killer whales (Orcinus orca). Naturwissenschaften DOI 10.1007/s00114-010-0657-z, published online 09 March 2010.
ABSTRACT
A few species of mammals produce group- specific vocalisations that are passed on by learning, but the function of learned vocal variation remains poorly understood. Resident killer whales live in stable matrilineal groups with repertoires of seven to 17 stereotyped call types. Some types are shared among matrilines, but their structure typically shows matriline-specific differences. Our objective was to analyse calls of nine killer whale matrilines in British Columbia to test whether call similarity primarily reflects social or genetic relationships. Recordings were made in 1985-1995 in the presence of focal matrilines that were either alone or with groups with non-overlapping repertoires. We used neural network discrimination performance to measure the similarity of call types produced by different matrilines and determined matriline association rates from 757 encounters with one or more focal matrilines. Relatedness was measured by comparing variation at 11 microsatellite loci for the oldest female in each group. Call similarity was positively correlated with association rates for two of the three call types analysed. Similarity of the N4 call type was also correlated with matriarch relatedness. No relationship between relatedness and association frequency was detected. These results show that call structure reflects relatedness and social affiliation, but not because related groups spend more time together. Instead, call structure appears to play a role in kin recognition and shapes the association behaviour of killer whale groups. Our results therefore support the hypothesis that increasing social complexity plays a role in the evolution of learned vocalisations in some mammalian species.
Full paper HERE.
Deecke, V. B., Ford, J. K. B. 2002. Selective habituation shapes acoustic predator recognition in harbor seals Nature 420(6912):171-3 · December 2002.
ABSTRACT
Predation is a major force in shaping the behaviour of animals, so that precise identification of predators will confer substantial selective advantages on animals that serve as food to others. Because experience with a predator can be lethal, early researchers studying birds suggested that predator recognition does not require learning. However, a predator image that can be modified by learning and experience will be advantageous in situations where cues associated with the predator are highly variable or change over time. In this study, we investigated the esponse of harbour seals (Phoca vitulina) to the underwater calls of different populations of killer whales (Orcinus orca). We found that the seals responded strongly to the calls of mammal-eating killer whales and unfamiliar fish-eating killer whales but not to the familiar calls of the local fish-eating population. This demonstrates that wild harbour seals are capable of complex acoustic discrimination and that they modify their predator image by selectively habituating to the calls of harmless killer whales. Fear in these animals is therefore focused on local threats by learning and experience.
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Deecke, V.B., Ford, J.K.B., and Spong, P. 2000. Dialect Change in Resident Killer Whales (Orcinus orca): Implications for Vocal Learning and Cultural Transmission. Anim. Behav.60(5):619-638.
ABSTRACT
Variation in vocal signals among populations and social groups of animals provides opportunities for the study of learning and its importance in generating and maintaining variation in behavioural traits. In this study, we analyse 2 call types made by 2 matrilineal social groups of resident killer whales (Orcinus orca) over a period of 14 years. We use a neural network-based index of acoustic similarity to identify mechanisms of call differentiation. A test for structural modification of the calls detected significant changes in one call type in both groups, but not in the other. For the modified call type, the rate of differentiation between the two groups was significantly lower than the rate of modification within either group showing that calls are modified in a similar fashion in the two groups. An analysis of structural parameters detected no strong directionality in the change. The detected pattern of call modification could be caused by maturational changes to the calls, or, if killer whale dialects are learned behavioural traits, cultural drift in the structure of the calls together with horizontal transmission of modifications between the two groups. Such vocal matching between members of different matrilineal groups would suggest that vocal learning is not limited to vertical transmission from mother to offspring, as required for some models of gene-culture coevolution.
Deecke, V.B., J.K.B. Ford, P. Spong (1999). Quantifying complex patterns of bioacoustic variation: Use of a neural network to compare killer whale (Orcinus orca) dialects. Journal of the Acoustical Society of America. Vol.105 i4, p. 2499-2507.
ABSTRACT
A quantitative measure of acoustic similarity is crucial to any study comparing vocalizations of different species, social groups, or individuals. The goal of this study was to develop a method of extracting frequency contours from recordings of pulsed vocalizations and to test a non-linear index of acoustic similarity based on the error of an artificial neural network at classifying them. Since the performance of neural networks depends on the amount of consistent variation in the training data, this technique can be used to assess such variation from samples of acoustic signals. The frequency contour extraction and the neural network index were tested on samples of one call type shared by 9 social groups of killer whales. For comparison, call similarity was judged by 3 human subjects in pairwise classification tasks. The results showed a significant correlation between the neural network index and the similarity ratings by the subjects. Both measures of acoustic similarity were significantly correlated with the groups' association patterns, indicating that both methods of quantifying acoustic similarity are biologically meaningful. An index based on neural network analysis therefore represents an objective and repeatable means of measuring acoustic similarity, and allows comparison of results across studies, species, and time.
Deecke, V.B. (1998). Stability and Change of killer whale (Orcinus orca) dialects. M.Sc. thesis, The University of British Columbia, Vancouver, BC, 114 pp.
ABSTRACT
Vocal dialects have been described in many species, but most studies so far have focused on territorial species such as songbirds and humans. This study investigates patterns of structural variation in the stereotyped calls of 9 matrilineal units of killer whales (Orcinus orca) with congruent home ranges.
In Chapter I, I describe an index of acoustic similarity based on neural network analysis of frequency contours. I test this index on simulated signals, and compare it to similarity ratings from three human subjects. The index could discriminate along global differences in contour frequency, as well as localized differences in frequency and shape. It rated similarity comparably to humans, since differences between ratings among subjects exceeded differences between subject ratings and the neural network index.
In the second Chapter, I analyse 2 call types used by 2 groups over a 12 year period to identify mechanisms of vocal differentiation. A test for structural modification detected significant changes in one call type in both groups, but not in the other. The rate of differentiation between both groups was significantly lower for the modified call type than the rate of modification in one group showing that modifications are transmitted between groups. Results of an analysis of structural parameters are consistent with a theory of structural drift.
In Chapter III, I quantify patterns of structural variation for 4 call types shared by 9 matrilineal units. Patterns are consistent across some call types, and similarity ratings for two call types are correlated with the frequency of association among groups. This presents additional evidence for the role of cultural transmission in maintaining structural similarity of shared calls.
This study shows that discrete calls of killer whales are modifiable behavioural traits and transmitted through learning. Since multiple vocal traditions persist in spite of frequent acoustic contact between their members, this study presents evidence for selective copying in resident killer whales. If association patterns reflect kinship among matrilineal units as they do among individuals and among communities, similarity of shared call types indicates the degree of maternal relatedness, and may function in kin recognition or mate choice.
Erbe, Christine (2002). Underwater noise of whale-watching boats and potential effects on killer whales (Orcinus orca) based on an acoustic impact model. Marine Mammal Science, Volume 18 Issue 2 Page 394-418.
ABSTRACT
Underwater noise of whale-watching boats was recorded in the popular killer whale-watching region of southern British Columbia and northwestern Washington State. A software sound propagation and impact assessment model was applied to estimate zones around whale-watching boats where boat noise was audible to killer whales, where it interfered with their communication, where it caused behavioral avoidance, and where it possibly caused hearing loss. Boat source levels ranged from 145 to 169 dB re 1 μPa @ 1 m, increasing with speed. The noise of fast boats was modeled to be audible to killer whales over 16 km, to mask killer whale calls over 14 km, to elicit a behavioral response over 200 m, and to cause a temporary threshold shift (TTS) in hearing of 5 dB after 30–50 min within 450 m. For boats cruising at slow speeds, the predicted ranges were 1 km for audibility and masking, 50 m for behavioral responses, and 20 m for TTS. Superposed noise levels of a number of boats circulating around or following the whales were close to the critical level assumed to cause a permanent hearing loss over prolonged exposure. These data should be useful in developing whale-watching regulations. This study also gave lower estimates of killer whale call source levels of 105–124 dB re 1 μPa.
Fais, A., M. Johnson, M. Wilson, N. Aguilar Soto & P. T. Madsen (2016) Sperm whale predator-prey interactions involve chasing and buzzing, but no acoustic stunning. Scientific Reports 6, Article number: 28562 (2016) doi:10.1038/srep28562.
ABSTRACT
The sperm whale carries a hypertrophied nose that generates powerful clicks for long-range echolocation. However, it remains a conundrum how this bizarrely shaped apex predator catches its prey. Several hypotheses have been advanced to propose both active and passive means to acquire prey, including acoustic debilitation of prey with very powerful clicks. Here we test these hypotheses by using sound and movement recording tags in a fine-scale study of buzz sequences to relate the acoustic behaviour of sperm whales with changes in acceleration in their head region during prey capture attempts. We show that in the terminal buzz phase, sperm whales reduce inter-click intervals and estimated source levels by 1–2 orders of magnitude. As a result, received levels at the prey are more than an order of magnitude below levels required for debilitation, precluding acoustic stunning to facilitate prey capture. Rather, buzzing involves high-frequency, low amplitude clicks well suited to provide high-resolution biosonar updates during the last stages of capture. The high temporal resolution helps to guide motor patterns during occasionally prolonged chases in which prey are eventually subdued with the aid of fast jaw movements and/or buccal suction as indicated by acceleration transients (jerks) near the end of buzzes.
Full paper HERE.
Favaro, Livio, Silvana Neves, Stefano Furlati, Daniela Pessani, Vidal Martin, Vincent M. Janik1 (2016) Evidence suggests vocal production learning in a cross-fostered Risso’s dolphin (Grampus griseus). Animal Cognition · February 2016 DOI: 10.1007/s10071-016-0961-x.
ABSTRACT
Vocal learning is a rare skill in mammals, and we have limited information about the contexts in which they use it. Previous studies suggested that cetaceans in general are skilled at imitating sounds, but only few species have been studied to date. To expand this investigation to another species and to investigate the possible influence of the social environment on vocal learning, we studied the whistle repertoire of a female Risso’s dolphin (Grampus griseus) that was stranded at an early age and was subsequently raised in a group of bottlenose dolphins (Tursiops truncatus). We show that this cross-fostered animal produced vocal signals more akin to those of its Tursiops poolmates than those of Risso’s dolphins in the wild. This is one of very few systematic cross-fostering studies in cetaceans and the first to suggest vocal production learning in the Risso’s dolphin. Our findings also suggest that social experience is a major factor in the development of the vocal repertoire in this species.
Full paper HERE.
Filatova, Olga A., Samarra, Filipa I.P., Deecke, Volker B., Ford, John K.B., Miller, Patrick J.O. and Yurk, Harald (2015) Cultural evolution of killer whale calls: background, mechanisms and consequences. Behaviour, 152 (15). pp. 2001-2038. . V 16(3): 261-280.
ABSTRACT
Cultural evolution is a powerful process shaping behavioural phenotypes of many species including our own. Killer whales are one of the species with relatively well-studied vocal culture. Pods have distinct dialects comprising a mix of unique and shared call types; calves adopt the call repertoire of their matriline through social learning. We review different aspects of killer whale acoustic communication to provide insights into the cultural transmission and gene-culture co- evolution processes that produce the extreme diversity of group and population repertoires. We argue that the cultural evolution of killer whale calls is not a random process driven by steady error accumulation alone: temporal change occurs at different speeds in different components of killer whale repertoires, and constraints in call structure and horizontal transmission often degrade the phylogenetic signal. We discuss the implications from bird song and human linguistic studies, and propose several hypotheses of killer whale dialect evolution.
Full paper HERE.
Filatova O.A., Fedutin I.D., Burdin A.M., Hoyt E. (2007) The structure of the discrete call repertoire of killer whales Orcinus orca from Southeast Kamchatka Bioacoustics. V 16(3): 261-280.
ABSTRACT
The problem of categorization arises in any classification system because classes should be discrete while the characteristics of most natural objects and aspects of nature are more or less gradual. In systematics, this problem usually is solved by creating several levels of categories, such as class, order, family, genus and species. In the existing killer whale discrete call classification, only two levels occur - call type and call subtype. In this paper we describe structural categories at a broader level than call type in the discrete sounds of killer whales and compare these categories between and within vocal clans in a community of resident killer whales from Southeast Kamchatka, Russian Far East, and also with killer whales outside this community. We found four main classes of discrete calls in the repertoire of resident killer whales from Southeast Kamchatka. The calls of Southeast Kamchatka transient killer whales and Sakhalin killer whales do not fall into these classes. This suggests that the resident killer whale community from Southeast Kamchatka has some rules defining the structure of calls which are typical for this community. Consequently, all resident killer whales from Southeast Kamchatka can be said to share the same vocal tradition.
A pdf copy is available upon request from alazor@rambler.ru
Foote, Andrew D., Richard W. Osborne, A. Rus Hoelzel (2008) Temporal and Contextual Patterns of Killer Whale (Orcinus orca) Call Type Production. Ethology Volume 114 Issue 6 Page 599-606, June 2008
ABSTRACT
Fish-eating killer whales Orcinus orca in the northeastern Pacific live in highly stable matrifocal social groups called pods. Each pod produces a repertoire of seven or more stereotyped call types. We compared the relative production of call types of free-ranging killer whale pods over time and between social contexts. The relative production of call types by each pod during directional travel was distinct over a 27-yr period; however, both temporal stability and pod distinctiveness were strongly influenced by a subset of dominant call types within the repertoire of each pod. Some call types within the repertoires contain biphonation (two overlapping independently modulated tones) and have a higher estimated active space than call types containing just one tone. In multi-pod aggregations the relative production of the dominant call types of each pod decreased and the relative production of a subset of call types that are rarely recorded from single-pod groupings increased. The majority of these contained biphonation. The data suggest a distinction between a subset of dominant call types that may function to identify the pod and a subset of less common call types including several call types containing biphonation that are more commonly produced during inter-pod affiliations.
Foote, Andrew D. and Jeffrey A. Nystuen (2008) Variation in call pitch among killer whale ecotypes Acoustical Society of America. DOI: 10.1121/1.2836752 Pages: 1747–1752.
ABSTRACT
Vocal structure can vary between populations due to variation in ecology-dependent selection pressures, such as masking by background noise and the presence of eavesdroppers. Signalers can overcome these obstacles to effective communication by avoiding frequencies that overlap with background noise or the audible range of eavesdroppers. In the Northeastern Pacific three “ecotypes” of killer whale coexist in sympatry, but differ from one another in their diet and habitat use. The minimum frequency Fmin and the frequency containing the peak energy between 0 and 10 kHz Fpeak of a random sample of calls produced by a population of each ecotype was measured. The offshore ecotype produced calls with a significantly higher Fmin than the other ecotypes, which could be a strategy to avoid masking by low frequency chronic bandlimited wind noise found in the offshore environment. The resident ecotype produced calls with a significantly higher Fmin and Fpeak than the transient ecotype. This could be to reduce detection by their salmonid prey, which has a narrow band, low frequency auditory range.
Full paper HERE.
Foote, Andrew D., Rachael M. Griffin, David Howitt, Lisa Larsson, Patrick J. O. Miller and A. Rus Hoelzel (2006) Killer whales are capable of vocal learning. Biol. Lett. doi:10.1098/rsbl.2006.0525.
ABSTRACT
The production learning of vocalizations by manipulation of the sound production organs to alter the physical structure of sound has been demonstrated in only a few mammals. In this natural experiment, we document the vocal behaviour of two juvenile killer whales, Orcinus orca, separated from their natal pods, which are the only cases of dispersal seen during the three decades of observation of their populations. We find mimicry of California sea lion (Zalophus californianus) barks, demonstrating the vocal production learning ability for one of the calves. We also find differences in call usage (compared to the natal pod) that may reflect the absence of a repertoire model from tutors or some unknown effect related to isolation or context.
Full paper HERE.
Andrew D. Foote (2005). Correlates of variability in killer whale stereotyped call repertoires. Whale-call response to masking boat noise. A thesis submitted to the University of Durham in partial fulfilment of the requirements for the degree of Master of Science. September 2005.
ABSTRACT
Killer whales vocalisations include repertoires of stereotyped cal types (Ford 1984). There is strong evidence that these vocalisations are learnt (Hoelzel and Osborne 1986; Bain 1989; Deecke et al. 2000; Yurk et al. 2002). Call types can be group specific or shared amongst a number of groups, depending upon the social structure of the population or the call type (Ford 1991; Deecke 2003). It is thought that these call types function in the group cohesion and coordination (Hoelzel and Osborne 1986; Ford 1989, 1991; Miller 2000, 2002). Some call types contain two overlapping, independently modulated, components each having different transmission properties, these call types have a higher estimated active space than single-component call types. This thesis investigates the evolution of these call type repertoires, focusing on call type usage and structure of the Southern Resident population over a period of 27 years, but including comparisons with other populations. I present evidence of heterospecific mimicry and further evidence for vocal production and usage learning in killer whales. I compared the relative frequency of use of call types between two time periods (1977-81 & 2001-2003) and between contexts, such as direction changes with directional travel and multi-pod aggregations with single pods. I found a strong correlation of relative call type usage for each pod between the two time periods and each pod was easily acoustically distinguishable from the other two pods in both periods. The implications of these results for a role of call type repertoires in kin recognition are discussed. The least cohesive pod produced a significantly higher proportion of two component call types than the other two more cohesive pods. Lone whales separated from their pod also used a rare subset of two-component call types rather than their pod's main call types. In recordings of multi-pod aggregations we recorded a high proportion of the same subset of two-component call types not commonly produced by any of the three pods individually, these call types were used in significantly higher proportions when all three pods were converging or socialising rather than travelling. These contextual correlates suggest that call types are selectively used and shared between groups based on their transmission properties. Each of the Southern Resident pods, J, K and L, were found to increase the duration of their primary call type 10-15% in the presence of vessel noise in recordings made between 2001 & 2003. This response was not detected in recording from two earlier time periods, (1977-1981 or 1989-1992). This change in behaviour correlated with an increase over the past decade in vessel presence around this population and may be an anti-masking strategy. I also compared the range and mean minimum and maximum fundamental frequency of the call types within the repertoires of six North Pacific killer whale populations. There was a degree of homogeneity in the range of call type fundamental frequencies within the repertoires of populations of the same ecotype, but differences between ecotypes. Offshore call types generally had a higher pitch fundamental frequency than transient or resident call types. All three resident populations had call types in their repertoires that had a maximum fundamental frequency 3 kHz higher than found in any transient call type.
Full paper HERE.
Andrew D. Foote, Richard W. Osborne and A. Rus Hoelzel (2004). Whale-call response to masking boat noise. NATURE|VOL 428 | 29 APRIL 2004.
ABSTRACT
Background noise can interfere with the detection and discrimination of crucial signals among members of a species. Here we investigate the vocal behaviour in the presence and absence of whale-watcher boat traffic of three social groups (pods) of killer whales (Orcinus orca) living in the nearshore waters of Washington state. We find longer call durations in the presence of boats for all three pods, but only in recent recordings made following a period of increasing boat traffic. This result indicates that these whales adjust their behaviour to compensate for anthropogenic noise once it reaches a threshold level.
Full article HERE.
Ford, J. K. B. (1991). Vocal traditions among resident killer whales (Orcinus orca) in coastal waters of British Columbia. Can. J. Zool. 69(6): 1454–1483 (1991).
ABSTRACT
Underwater vocalizations were recorded during repeated encounters with 16 pods, or stable kin groups, of resident killer whales (Orcinus orca) off the coast of British Columbia. Pods were identified from unique natural markings on individuals. Vocal exchanges within pods were dominated by repetitious, discrete calls. Pods each produced 7–17 (mean 10.7) types of discrete calls. Individuals appear to acquire their pod's call repertoire by learning, and repertoires can persist with little change for over 25 years. Call repertoires differed significantly among pods in the resident population. The 16 pods formed four distinct acoustic associations, or clans, each having a unique repertoire of discrete calls, or vocal tradition. Pods within a clan shared several call types, but no sharing took place among clans. Shared calls often contained structural variations specific to each pod or group of pods in the clan. These variants and other differences in acoustic behaviour formed a system of related pod-specific dialects within the vocal tradition of each clan. Pods from different clans often travelled together, but observed patterns of social associations were often independent of acoustic relationships. It is proposed that each clan comprises related pods that have descended from a common ancestral group. New pods formed from this ancestral group through growth and matrilineal division of the lineage. The formation of new pods was accompanied by divergence of the call repertoire of the founding group. Such divergence resulted from the accumulation of errors in call learning across generations, call innovation, and call extinction. Pod-specific repertoires probably serve to enhance the efficiency of vocal communication within the group and act as behavioural indicatorsof pod affiliation. The striking differences among the vocal traditions of different clans suggest that each is an independent matriline.
Ford, J. K. B. (1991). Family Fugues. Natural History, March, 1991, p. 68-76.
Quotes: "Like all members of the dolphin family, killer whales rely heavily on underwater sound for both navigation and communication."
"After recording the whales on many occasions over several years, I learned that most resident pods repetitively emit about a dozen different types of what I term discrete calls—each distinct enough to be identified by ear."
"Whenever a pod is routinely foraging or traveling, calls tend to be stereotyped, varying only slightly in duration or pitch. Some situations create excitement among the whales, however, such as when two pods meet after an extended period of separation. Then vocal activity is often intense, and the calls produced tend to be higher in pitch, shorter in duration, and repeated more rapidly than the same calls given by relaxed or resting whales. And when whales are interacting physically-chasing, pushing, and nipping each other-or when juveniles play together, they incorporate many abberrations into their normal calls and emit an array of squeaks, squawks, and whistles that are seldom, if ever, repeated in the same form."
"In more than seventeen years of study, no whale has yet been seen to transfer permanently from one group to another. The pods bulls-once thought to be the breeding 'harem masters' of the group-are simply the mature male offspring of the females in the pod."
"As the new pods spent more and more time apart and developed their own social identities, their repertoires of calls began gradually changing through a process of cultural drift."
"Dialects, too are slow to change. The southern community pod J1, for example, is making the same calls today as in 1958, when the Canadian navy made recordings."
"What, if any, function is served by vocal dialects in killer whales is not certain."
"I'm sure individuals are able to identify whales from other pods by their dialects, but I suspect that more information than simple pod affiliation is exchanged."
"With luck and perseverence, we may eventually be able to construct a global lexicon for this most exceptional species."
Herman, L.M., R.K. Uyeyama (1999). The dolphin's grammatical competency: Comments on Kako. Animal Learning & Behavior. Vol. 27:1, p. 18-23.
ABSTRACT
Kako (1999) reviews the evidence for syntactic competencies in several animal species exposed to artificial language systems, emphasizing the importance of core syntactic properties such as argument structure and closed-class items. We present evidence from our dolphin studies for the acquisition of the closed-class functionality of demonstratives, prepositions, conjunctions, and locatives. Sensitivity to argument structure is also evidenced by wholly untrained and consistent interpretations of the dolphin to probes of anomalous syntactic structures. These results are generated within our comprehension-based paradigm, which enables us to provide convincing objective evidence for the development and generalization of concepts by the dolphin subject. Demonstrations of animal language competencies may illuminate certain aspects of human linguistic competence by suggesting that the particular modeled subsets can derive from general cognitive mechanisms, rather than language-specific ones.
Herzing, Denise (2010). SETI meets a social intelligence: Dolphins as a model for real-time interaction and communication with a sentient species. Acta Astronautica Volume 67, Issues 11-12, December 2010, Pages 1451-1454.
ABSTRACT
In the past SETI has focused on the reception and deciphering of radio signals from potential remote civilizations. It is conceivable that real-time contact and interaction with a social intelligence may occur in the future. A serious look at the development of relationship, and deciphering of communication signals within and between a non-terrestrial, non-primate sentient species is relevant. Since 1985 a resident community of free-ranging Atlantic spotted dolphins has been observed regularly in the Bahamas. Life history, relationships, regular interspecific interactions with bottlenose dolphins, and multi-modal underwater communication signals have been documented. Dolphins display social communication signals modified for water, their body types, and sensory systems. Like anthropologists, human researchers engage in benign observation in the water and interact with these dolphins to develop rapport and trust. Many individual dolphins have been known for over 20 years. Learning the culturally appropriate etiquette has been important in the relationship with this alien society. To engage humans in interaction the dolphins often initiate spontaneous displays, mimicry, imitation, and synchrony. These elements may be emergent/universal features of one intelligent species contacting another for the intention of initiating interaction. This should be a consideration for real-time contact and interaction for future SETI work.
Holt, Marla M., Dawn P. Noren, Val Veirs, Candice Emmons and Scott Viers (2009). Speaking up: Killer whales (Orcinus orca) increase their call amplitude in response to vessel noise. J. Acoust. Soc. Am. Volume 125, Issue 1, pp. EL27-EL32 (January 2009).
ABSTRACT
This study investigated the effects of anthropogenic sound exposure on the vocal behavior of free-ranging killer whales. Endangered Southern Resident killer whales inhabit areas including the urban coastal waters of Puget Sound near Seattle, WA, where anthropogenic sounds are ubiquitous, particularly those from motorized vessels. A calibrated recording system was used to measure killer whale call source levels and background noise levels (1–40 kHz). Results show that whales increased their call amplitude by 1 dB for every 1 dB increase in background noise levels. Furthermore, nearby vessel counts were positively correlated with these observed background noise levels.
Full paper HERE.
Juliana Houghton, Marla M. Holt, Deborah A. Giles, M. Bradley Hanson, Candice K. Emmons, Jeffrey T. Hogan, Trevor A. Branch, Glenn R. VanBlaricom (2015). The Relationship between Vessel Traffic and Noise Levels Received by Killer Whales (Orcinus orca). PLOS Published: December 2, 2015 DOI: 10.1371/journal.pone.0140119.
ABSTRACT
Whale watching has become increasingly popular as an ecotourism activity around the globe and is beneficial for environmental education and local economies. Southern Resident killer whales (Orcinus orca) comprise an endangered population that is frequently observed by a large whale watching fleet in the inland waters of Washington state and British Columbia. One of the factors identified as a risk to recovery for the population is the effect of vessels and associated noise. An examination of the effects of vessels and associated noise on whale behavior utilized novel equipment to address limitations of previous studies. Digital acoustic recording tags (DTAGs) measured the noise levels the tagged whales received while laser positioning systems allowed collection of geo-referenced data for tagged whales and all vessels within 1000 m of the tagged whale. The objective of the current study was to compare vessel data and DTAG recordings to relate vessel traffic to the ambient noise received by tagged whales. Two analyses were conducted, one including all recording intervals, and one that excluded intervals when only the research vessel was present. For all data, significant predictors of noise levels were length (inverse relationship), number of propellers, and vessel speed, but only 15% of the variation in noise was explained by this model. When research-vessel-only intervals were excluded, vessel speed was the only significant predictor of noise levels, and explained 42% of the variation. Simple linear regressions (ignoring covariates) found that average vessel speed and number of propellers were the only significant correlates with noise levels. We conclude that vessel speed is the most important predictor of noise levels received by whales in this study. Thus, measures that reduce vessel speed in the vicinity of killer whales would reduce noise exposure in this population.
Full paper HERE.
Ivanov, M.P. (2009). Study of Dolphin Communicational Behavior: Procedure, Motor and Acoustic Parameters. Journal of Evolutionary Biochemistry and Physiology, 2009, Vol. 45, No. 6, pp. 696—705.
ABSTRACT
First results of experiments on the acoustic communication of dolphins are reported, with demonstration of their motor reaction of observation of a respondent, the reaction being the same for all participants of the dialogue, i.e., the turn of head or trunk towards each other during translation/reception of information. The procedure allows comparing unequivocally the acoustic signals with the behavioral acts of the animals during the experiment. All stages of the animals' learning are shown as well as oscillograms of acoustic signals during the echolocation communication at differentiation of targets and acoustic commucational behavior. The initial model of the physiological experiment served the known procedure of study of formation of the learning set, the stimulus of the communication reaction of observers being the unrealized action with the increasing emotional load, on the peak of which the inevitable acoustic intervention in the respondent's work occurs, which proves indisputably the model of the communicational behavior.
Jones, Guenevere J. and Laela S. Sayigh (2002). Geographic varition in rates of vocal production of free-ranging bottlenose dolphins. Marine Mammal Science: Vol. 18, No. 2, pp. 374–393.
ABSTRACT
Echolocation and whistle production, group sizes, and activities of free-ranging bottlenose dolphins were compared across four regions (Wilmington, NC Intracoastal Waterway [ICW]; Wilmington coastline; Southport, NC coastline; and Sarasota, FL inshore waters). Number of whistles and echolocation bouts differed significantly across sites. Dolphins whistled significantly more in Southport than in the other sites, independent of group size. Unlike at the other sites, dolphin vocalizations in Southport did not vary significantly across activities; this difference may be due to the fact that Southport animals were often found behind shrimp-trawling vessels, which may affect their behavior. Resident Sarasota dolphins vocalized significantly less than dolphins at the NC sites. At most sites, echolocation production per dolphin decreased as group size increased, supporting the idea that echolocation information is shared. In the ICW and Sarasota, echolocation production per dolphin was highest while feeding, indicating that echolocation is used in foraging. At all sites but Southport, whistle production per dolphin was highest while socializing, indicating that whistles are used in communication. Overall, these data show that dolphins have different vocal and activity patterns at different sites; thus, caution should be used when extrapolating results from one study site to another.
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King, Stephanie L. (e-mail: vj@st-andrews.ac.uk), Laela S. Sayigh, Randall S. Wells, Wendi Fellner and Vincent M. Janik. Vocal copying of individually distinctive signature whistles in bottlenose dolphins. Proc. R. Soc. B 22 April 2013 vol. 280 no. 1757 20130053.
ABSTRACT
Vocal learning is relatively common in birds but less so in mammals. Sexual selection and individual or group recognition have been identified as major forces in its evolution. While important in the development of vocal displays, vocal learning also allows signal copying in social interactions. Such copying can function in addressing or labelling selected conspecifics. Most examples of addressing in non-humans come from bird song, where matching occurs in an aggressive context. However, in other animals, addressing with learned signals is very much an affiliative signal. We studied the function of vocal copying in a mammal that shows vocal learning as well as complex cognitive and social behaviour, the bottlenose dolphin (Tursiops truncatus). Copying occurred almost exclusively between close associates such as mother–calf pairs and male alliances during separation and was not followed by aggression. All copies were clearly recognizable as such because copiers consistently modified some acoustic parameters of a signal when copying it. We found no evidence for the use of copying in aggression or deception. This use of vocal copying is similar to its use in human language, where the maintenance of social bonds appears to be more important than the immediate defence of resources.
Ladegaard, Michael, Jason Mulsow, Dorian S. Houser, Frants Havmand Jensen, Mark Johnson, Peter Teglberg Madsen, James J. Finneran (2019). Dolphin echolocation behaviour during active long-range target approaches. Journal of Experimental Biology 2019 222: jeb189217 doi: 10.1242/jeb.189217 Published 25 January 2019.
ABSTRACT
Echolocating toothed whales generally adjust click intensity and rate according to target range to ensure that echoes from targets of interest arrive before a subsequent click is produced, presumably facilitating range estimation from the delay between clicks and returning echoes. However, this click–echo–click paradigm for the dolphin biosonar is mostly based on experiments with stationary animals echolocating fixed targets at ranges below ~120 m. Therefore, we trained two bottlenose dolphins instrumented with a sound recording tag to approach a target from ranges up to 400 m and either touch the target (subject TRO) or detect a target orientation change (subject SAY). We show that free-swimming dolphins dynamically increase interclick interval (ICI) out to target ranges of ~100 m. TRO consistently kept ICIs above the two-way travel time (TWTT) for target ranges shorter than ~100 m, whereas SAY switched between clicking at ICIs above and below the TWTT for target ranges down to ~25 m. Source levels changed on average by 17log10(target range), but with considerable variation for individual slopes (4.1 standard deviations for by-trial random effects), demonstrating that dolphins do not adopt a fixed automatic gain control matched to target range. At target ranges exceeding ~100 m, both dolphins frequently switched to click packet production in which interpacket intervals exceeded the TWTT, but ICIs were shorter than the TWTT. We conclude that the click–echo–click paradigm is not a fixed echolocation strategy in dolphins, and we demonstrate the first use of click packets for free-swimming dolphins when solving an echolocation task.
Leeney, Ruth H., David Carslake, and Simon H. Elwen (2011). Using Static Acoustic Monitoring to Describe Echolocation Behaviour of Heaviside's Dolphins (Cephalorhynchus heavisidii) in Namibia. Aquatic Mammals 2011, 37(2), 151-160.
ABSTRACT
Static acoustic monitoring is a cost-effective, low-effort means of gathering large datasets on echolocation click characteristics and habitat use by odontocetes. Heaviside's dolphins (Cephalorhynchus heavisidii) were monitored using an acoustic monitoring unit, the T-POD, in July 2008 at a site of known high abundance for this species in Walvis Bay, Namibia. The T-POD successfully detected clicks from Heaviside's dolphins, and these clicks were detected in the 120 to 140 kHz frequency range. A distinct diel pattern to the hourly mean inter-click interval was observed, with higher values during daylight hours than at night, suggesting that click trains are produced at faster rates at night time. There was no apparent diel pattern in the proportion of buzz trains produced, however. A diel pattern in click activity was observed, with many more detection-positive minutes per hour recorded between dusk and dawn, and vocalization activity dropping to low levels in the middle of the day. This corresponded with visual observations made on abundance of dolphins in the study area. These results suggest that Heaviside's dolphins use this site primarily during the night. Static acoustic monitoring proved to be an effective technique for monitoring patterns of habitat use by Heaviside's dolphins.
May-Collado, Laura J., Ingi Agnarsson, Douglas Wartzok (2007). Phylogenetic review of tonal sound production in whales in relation to sociality. BMC Evolutionary Biology 7:136.
ABSTRACT
Background
It is widely held that in toothed whales, high frequency tonal sounds called 'whistles' evolved in association with 'sociality' because in delphinids they are used in a social context. Recently, whistles were hypothesized to be an evolutionary innovation of social dolphins (the "dolphin hypothesis"). However, both 'whistles' and 'sociality' are broad concepts each representing a conglomerate of characters. Many non-delphinids, whether solitary or social, produce tonal sounds that share most of the acoustic characteristics of delphinid whistles. Furthermore, hypotheses of character correlation are best tested in a phylogenetic context, which has hitherto not been done. Here we summarize data from over 300 studies on cetacean tonal sounds and social structure and phylogenetically test existing hypotheses on their co-evolution.
Results
Whistles are 'complex' tonal sounds of toothed whales that demark a more inclusive clade than the social dolphins. Whistles are also used by some riverine species that live in simple societies, and have been lost twice within the social delphinoids, all observations that are inconsistent with the dolphin hypothesis as stated. However, cetacean tonal sounds and sociality are intertwined: (1) increased tonal sound modulation significantly correlates with group size and social structure; (2) changes in tonal sound complexity are significantly concentrated on social branches. Also, duration and minimum frequency correlate as do group size and mean minimum frequency.
Conclusions
Studying the evolutionary correlation of broad concepts, rather than that of their component characters, is fraught with difficulty, while limits of available data restrict the detail in which component character correlations can be analyzed in this case. Our results support the hypothesis that sociality influences the evolution of tonal sound complexity. The level of social and whistle complexity are correlated, suggesting that complex tonal sounds play an important role in social communication. Minimum frequency is higher in species with large groups, and correlates negatively with duration, which may reflect the increased distances over which non-social species communicate. Our findings are generally stable across a range of alternative phylogenies. Our study points to key species where future studies would be particularly valuable for enriching our understanding of the interplay of acoustic communication and sociality.
Full paper HERE.
Madsen, Peter T. , Ursula Siebert, and Coen P. H. Elemans. Toothed whales use distinct vocal registers for echolocation and communication. Science. 2 Mar 2023. Vol 379, Issue 6635
Echolocating toothed whales (odontocetes) capture fast-moving prey in dark marine environments, which critically depends on their ability to generate powerful, ultrasonic clicks. How their supposedly air-driven sound source can produce biosonar clicks at depths of >1000 meters, while also producing rich vocal repertoires to mediate complex social communication, remains unknown. We show that odontocetes possess a sound production system based on air driven through nasal passages that is functionally analogous to laryngeal and syringeal sound production. Tissue vibration in different registers produces distinct echolocation and communication signals across all major odontocete clades, and thus provides a physiological basis for classifying their vocal repertoires. The vocal fry register is used by species from porpoises to sperm whales for generating powerful, highly air-efficient echolocation clicks.
Access to full paper HERE.
McDonald, M. A., C. G. Fox (1999). Passive acoustic methods applied to fin whale population density estimation. J. Acoust. Soc. Am. Vol. 105:5, p. 2643-?.
Note: This paper demonstrates the feasibility of using fixed arrays of deep-sea hydrophones to monitor populations of baleen whales. This technology could be adapted as an attraction in future high-tech marine parks, to receive data from the Navy's SOSUS acoustic detection array that is spread throughout the world's oceans, selecting only the whale voices, showing the actual populations of a variety of species with lighted displays in real time as they travel through their undersea realms.
Melcón, Mariana L., Amanda J. Cummins, Sara M. Kerosky, Lauren K. Roche, Sean M. Wiggins, John A. Hildebrand (2012). Blue Whales Respond to Anthropogenic Noise. PLoS ONE 7(2): e32681. doi:10.1371/journal.pone.0032681.
ABSTRACT
Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood.
Full paper HERE.
May-Collado, Laura J. and Douglas Wartzok (2008). A Comparison of Bottlenose Dolphin whistles in the Atlantic Ocean: Factors promoting whistle variation. Journal of Mammalogy, 89(5):1229–1240, 2008.
ABSTRACT
Whistles are narrowband, frequency-modulated sounds produced by many cetaceans. Whistles are extensively studied in delphinids, where several factors have been proposed to explain between- and within-species variation. We examined factors associated with geographic variation in whistles of common bottlenose dolphins (Tursiops truncatus) by assessing the role of ambient noise, noise from boats, and sympatry with other dolphin species, and reviewing and comparing whistle structure across populations in the western and eastern Atlantic Ocean. Whistles of adjacent populations differed, particularly in frequency parameters. A combination of factors may contribute to microgeographic whistle variation, including differences in ambient noise levels (dolphins produced relatively higher frequency whistles in the noisiest habitat), and differences in number of boats present (when multiple boats were present, dolphins whistled with greater frequency modulation and whistles were higher in maximum frequency and longer than when a single boat was present). Whistles produced by adjacent populations were relatively similar in structure. However, for clearly separated populations, the distance between them did not relate directly to whistle structure. We propose that plasticity in bottlenose dolphin whistles facilitates adaptation to local and changing conditions of their habitat, thus promoting variation between populations at different geographic scales.
Full paper HERE.
Miller, Lee A., 2006. Killer Whales and Herring: Using Sound to Get a Meal. 151st ASA Meeting, Providence, RI.
PRESENTATION
Norwegian and Icelandic killer whales use a variety of techniques to get their dinner, many of which are acoustic. In defense, their prey employ clever acoustical countermeasures of their own. Icelandic killer whales, as we have discovered, employ an additional strategy, apparently not shared by their Norwegian cousins, that may give them an extra advantage in capturing their prey.
Killer whales of the Northeast Atlantic feed primarily on herring. In Norwegian waters billions of herring migrate from open oceanic waters into deep fjords in the late fall to over winter. Here they form vast schools that move up and down in the water column in daily rhythms "waiting" for spring to approach. In February, they migrate about 1,000 km south to their spawning grounds, and then out to open waters again. Groups of killer whales follow the herring to cooperatively feed on this favored prey. Often the whales dive to over a hundred meters to drive herring up to shallower waters forcing the fish into tight groups by swimming around them and flashing their white bellies at them.
Full paper HERE.
Miller, Patrick J., 2006. Diversity in sound pressure levels and estimated active space of resident killer whale vocalizations. J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2006 May;192(5):449-59.
ABSTRACT
Signal source intensity and detection range, which integrates source intensity with propagation loss, background noise and receiver hearing abilities, are important characteristics of communication signals. Apparent source levels were calculated for 819 pulsed calls and 24 whistles produced by free-ranging resident killer whales by triangulating the angles-of-arrival of sounds on two beamforming arrays towed in series. Levels in the 1-20 kHz band ranged from 131 to 168 dB re 1 microPa at 1 m, with differences in the means of different sound classes (whistles: 140.2+/-4.1 dB; variable calls: 146.6+/-6.6 dB; stereotyped calls: 152.6+/-5.9 dB), and among stereotyped call types. Repertoire diversity carried through to estimates of active space, with "long-range" stereotyped calls all containing overlapping, independently-modulated high-frequency components (mean estimated active space of 10-16 km in sea state zero) and "short-range" sounds (5-9 km) included all stereotyped calls without a high-frequency component, whistles, and variable calls. Short-range sounds are reported to be more common during social and resting behaviors, while long-range stereotyped calls predominate in dispersed travel and foraging behaviors. These results suggest that variability in sound pressure levels may reflect diverse social and ecological functions of the acoustic repertoire of killer whales.
Full paper HERE.
Miller, Patrick J. O. (Biology Department, Woods Hole Oceanographic Institution), David E. Bain (Animal Behavior Program, University of Washington, Seattle) Within-pod variation in the sound production of a pod of killer whales, Orcinus orca. Animal Behaviour, Vol. 60, No. 5, Nov 2000, pp. 617-628.
ABSTRACT
Pod-specific calling behaviour of resident killer whales has been shown to include: discrete call types not shared among pods, different production rates of shared call types, and differences in the detailed structure of shared call types. To investigate the mechanisms leading to pod-specific calling, we compared the repertoire and structure of calls produced by three different matrilineal units within the same pod, and described call features encoding matrilineal-unit distinctiveness. The three matrilineal units had different production rates of shared calls, including one call type used almost exclusively by one matrilineal unit. Cross-validated discriminant function analyses revealed matrilineal-unit distinctive structure in five of the six shared call types examined, with duration of the terminal component being the most distinctive feature for all call types containing a terminal component. Calls generally consist of low- and high-frequency components that may follow different time-frequency contours. In our sample, a particular high-frequency contour was consistently paired with a particular low-frequency contour, both contours had roughly equal overall variability, and each contained independent matrilineal-unit distinctive information. The only call type that did not differ structurally between matrilineal units is reportedly used more in interpod meetings than in intrapod contexts. The differences in calling behaviour between matrilineal units were similar in form to previously described differences between pods, although more subtle. These results suggest that pod-specific calling behaviour in resident killer whales arises primarily as a consequence of accumulated drift or divergence between highly cohesive matrilineal units as they gradually separate into different pods. Request full text HERE.
Miller, Patrick J. O., A. D. Shapiro; P. L. Tyack & A. R. Solow Call-type matching in vocal exchanges of free-rangingresident killer whales, Orcinus orca. Animal Behaviour, 2004, 67, 1099e1107doi:10.1016/j.anbehav.2003.06.017.
ABSTRACT
Previous sound recordings of resident (fish-eating) killer whale groups have revealed matrilineal group-specific call repertoires and a strong tendency for calls of the same type to be produced in series. Vocal interactions between individual free-ranging animals, however, have remained unexplored because it has not been possible to identify signallers reliably with a single hydrophone. Here we link acoustic arrivals of calls on a towed hydrophone array with visual tracking of photo-identified individuals to ascribe calls to a focal animal when it was separated from other members of its matrilineal group by more than 35 m, and thereby out of visual range. We confirm that individual members of a matrilineal group share a repertoire of stereotyped calls, and we statistically examine timing of stereotyped calls produced by one individual relative to calls produced by other members of its group. Analysis of the intervals between stereotyped calls indicated that calls were produced in group bouts with a criterion interval of 19.6 s separating bouts. We were therefore careful to develop randomization tests that preserved call interval structure. Focal whales produced 36% of their calls within 5 s of a call from a nonfocal animal, four times more calls than expected by chance based upon a rotation randomization test. Consecutive calls produced by different individuals during group-calling bouts matched call type more than expected by chance. Vocal exchanges of stereotyped calls with type matching appear to be an important aspect of intragroup calling in killer whales, although the function of this calling behaviour remains to be explored.
Miller, P. (2002). Mixed-directionality of killer whale stereotyped calls: a direction of movement cue?
ABSTRACT
The functional and ecological consequences of the directional emission of sounds used for communication remain largely unexplored even though non-uniform radiation patterns have been reported across a wide range of taxa. In this study the spectral structure of stereotyped calls recorded from groups of travelling killer whales (Orcinus orca) moving consistently toward or away from a towed hydrophone array was measured by comparing the energy in high-frequency (>5 kHz) with that in low-frequency (1–5 kHz) bands. Relative energy in high-frequency bands was significantly greater when animals were moving toward the hydrophone array, but only in call types that contain a separately modulated high-frequency component. The difference in relative energy as a function of direction of movement was more than 10 dB at the fundamental frequency of the high-frequency component of the two most common types recorded, confirming a strong pattern of mixed-directionality in these calls. Changes in call spectra due to signaler orientation to a receiver may provide an intrinsic cue of a moving signaler's direction of movement. Killer whales have sensitive hearing over the frequency range of this potential cue, and their marked behavioral synchrony suggests its use. The direction of movement cue inherent in the directionality pattern of calls may be an efficient and reliable means for this and possibly other highly mobile species to coordinate behavior and regulate spacing relative to other individuals.
Moore, S. E. (Sea World Research Institute, Hubbs Marine Research Center), J. K. Francine (Sea World Research Institute, Hubbs Marine Research Center), A. F. Bowles (Sea World Research Institute, Hubbs Marine Research Center), and J. K. B. Ford (Vancouver Aquarium) (1988). Analysis of calls of killer whales (Orcinus orca) from Iceland and Norway. Rit Fiskideildar Vol. 11, p. 225-250.
ABSTRACT
Underwater recordings of killer whale calls were made off Norway and Iceland from 1983 through 1986 in association with efforts to photograph dorsal fins and saddles for identification of individual whales. Researchers collected eight hours of recordings near at least two pods off Norway and eight hours of recordings near at least five pods off Iceland. A preliminary description of discrete call types for whales from each area was completed using methods developed on well known pods of killer whales off British Columbia and Washington. Twenty-four discrete calls were described for whales off Iceland; 23 discrete call types were identified for whales off Norway. There was little evidence of calls shared between Icelandic and Norwegian pods.
Note: Sonograms of calls made in 1998 by Keiko (of Free Willy fame) were compared with the above calls and found to significantly match them, indicating Keiko has retained the ability to communicate vocally with his natal family.
Morisaka, T., R. C. Connor (2007). Predation by killer whales (Orcinus orca) and the evolution of whistle loss and narrow-band high frequency clicks in odontocetes. Journal of Evolutionary Biology (OnlineEarly Articles). doi:10.1111/j.1420-9101.2007.01336.x
ABSTRACT
A disparate selection of toothed whales (Odontoceti) share striking features of their acoustic repertoires including the absence of whistles and high frequency but weak (low peak-to-peak source level) clicks that have a relatively long duration and a narrow bandwidth. The non-whistling, high frequency click species include members of the family Phocoenidae, members of one genus of delphinids, Cephalorhynchus, the pygmy sperm whale, Kogia breviceps, and apparently the sole member of the family Pontoporiidae. Our review supports the "acoustic crypsis" hypothesis that killer whale predation risk was the primary selective factor favouring an echolocation and communication system in cephalorhynchids, phocoenids and possibly Pontoporiidae and Kogiidae restricted to sounds that killer whales hear poorly or not at all (< 2 and > 100 kHz).
Morton, A. B., J.C. Gale. and R.C. Prince. 1986. Sound and behavioral correlation in captive Orcinus orca. In: Kirkevold, B.C. and Lockhard, J.S. (eds.) Behavioral biology of killer whales. Alan R. Liss, Inc. New York. pp.
INTRODUCTION
The relationship between cetacean sounds and behaviors has been a topic of interest, frustration and confusion. The traditional approach attempted to correlate the occurrence of a sound with a specific behavior, e.g., as in the case of obvious behavioral stress and the emission of a "distress whistle" (Busnell and Driedzic, 1968; Caldwell and Caldwell, 1971; Wood, 1954). While the results have been positive they have also been inconclusive. A sound might be highly correlated with a particular activity but it might also be evinced in apparently unrelated activities. Thus with this method no definite pattern is ascertained.
In this study we looked at the percentage emission rather than the absolute occurrence of sounds. Instead of concentrating on one or two individual sounds we took a broad look at the overall usage of the sound in different behavioral activities of Orcinus orca. With this approach a relationship was found between sounds and behaviora states, i.e., "tranquility," "play" and "distress."
Oleson, Erin M., Sean M. Wiggins, and John A. Hildebrand (2006). Acoustic monitoring of resident, offshore, and transient killer whales off the Washington coast. J. Acoust. Soc. Am., Volume 120, Issue 5, p. 3015.
ABSTRACT
Three acoustically distinct populations of killer whales representing each of the known ecotypes (resident, offshore, transient) were recorded in the Summer–Fall of 2004 off the southern Olympic Coast of Washington. Two high-frequency acoustic recording packages (HARPs) continuously recording at 80-kHz sample rate were deployed to assess the seasonal occurrence of vocal odontocetes in this region. From mid-July to early-October the population-specific discrete calls of killer whales were heard on 8 days and were classified to population by Volker Deecke (UBC) and John Ford (DFO-Canada) using an acoustic ID catalogue. West Coast Transient killer whales producing calls of the California dialect were heard on three occasions from August through October. Offshore killer whales were heard twice in August–September, and Northern Resident killer whales were heard once in August. Although Northern Resident killer whales have been extensively studied within Puget Sound and coastal British Columbia, they have been visually sighted only once off the northern Olympic Peninsula, making their detection at this offshore southerly location unique. Endangered Southern Resident killer whales were not heard at this site from July–October. Analysis of year-round data from a site further offshore is underway. [Funded by Chief of Naval Operations- N45.]
Pirotta, Vanessa, Alana Grech, Ian D Jonsen, William F Laurance, Robert G Harcourt. (2018). Consequences of global shipping traffic for marine giants. Frontiers in Ecology and the Environment, First published: 05 December 2018.
ABSTRACT
Shipping routes in the ocean are analogous to terrestrial roads, in that they are regularly used thoroughfares that concentrate the movement of vessels between multiple locations. We applied a terrestrial road ecology framework to examine the ecological impacts of increased global shipping on “marine giants” (ie great whales, basking sharks [Cetorhinus maximus], and whale sharks [Rhincodon typus]). This framework aided in identifying where such “marine roads” and marine giants are likely to interact and the consequences of those interactions. We also reviewed known impacts of shipping routes on these species, and then applied the road ecology framework to detect unknown and potentially threatening processes. In the marine environment, such a framework can be used to incorporate knowledge of existing shipping impacts into management practices, thereby reducing the detrimental effects of future expansion of shipping routes on marine giants.
Rehn, Nicola; Olga A. Filatova, John W. Durban and Andrew D. Foote (2010). Cross-cultural and cross-ecotype production of a killer whale 'excitement' call suggests universality. Naturwissenschaften, DOI 10.1007/s00114-010-0732-5, published online 12 November 2010.
ABSTRACT
Facial and vocal expressions of emotion have been found in a number of social mammal species and are thought to have evolved to aid social communication. There has been much debate about whether such signals are culturally inherited or are truly biologically innate. Evidence for the innateness of such signals can come from cross-cultural studies. Previous studies have identified a vocalisation (the V4 or 'excitement' call) associated with high arousal behaviours in a population of killer whales in British Columbia, Canada. In this study, we compared recordings from three different socially and reproductively isolated ecotypes of killer whales, including five vocal clans of one ecotype, each clan having discrete culturally transmitted vocal traditions. The V4 call was found in recordings of each ecotype and each vocal clan. Nine independent observers reproduced our classification of the V4 call from each population with high inter-observer agreement. Our results suggest the V4 call may be universal in Pacific killer whale populations and that transmission of this call is independent of cultural tradition or ecotype. We argue that such universality is more consistent with an innate vocalisation than one acquired through social learning and may be linked to its apparent function of motivational expression.
Rehn, Nicola; Teichert, Stefanie; Thomsen, Frank (2007). Structural and temporal emission patterns of variable pulsed calls in free-ranging killer whales (Orcinus orca). Behaviour, Volume 144, Number 3, 2007, pp. 307-329(23).
ABSTRACT
Resident killer whales off Vancouver Island, British Columbia, produce variable burst pulsedcalls most commonly during close-range interactions such as socialising or social-travelling. Earlier studies indicated that variable calls are graded and can be arranged into a scale from low-frequency calls to high-frequency ones. These graded calls are often emitted in sequences, were call-classes of similar frequency follow one another more often than different classes. However, a detailed analysis of sequences was lacking to date. Therefore, our understanding of the function of variable calls during interactions among killer whales is rather limited. Simultaneous recordings of underwater vocalizations and behavioural observations from resident killer whales were collected off Vancouver Island, British Columbia during1996-2001. Socialising activities were divided into four categories: male-female, male-male, female-juvenile and juvenile-juvenile. Variable call sequences were analysed with RTS and SIGNAL acoustic-software. We found no positive correlation between group-size and number of used calls or the duration of sequences, indicating that only one or a few animals were involved in the production of each sequence. Furthermore, sequences were present in all four behaviour categories and the composition of the group had no influence on the duration of calls and used call-classes. One particular call class (V4) could be further separated into structurally distinct sub-classes. These sub-classes often formed rather stereotyped sequences. The results of our study indicate that sequences of variable calls emit broad motivational information that is not age or sex-related. Sequences of distinct sub-classes might encode more subtle information on emotional states during socialising. Therefore, variable calls might posses different functions, depending on the nature of the interaction. Thus, variable calls might be of great importance for close-range communication in wild killer whales.
Rendell, Luke, Sarah L. Mesnick, Merel L. Dalebout, Jessica Burtenshaw and Hal Whitehead (2011) Can Genetic Differences Explain Vocal Dialect Variation in Sperm Whales, Physeter macrocephalus? BEHAVIOR GENETICS DOI: 10.1007/s10519-011-9513-y.
ABSTRACT
Sperm whale social groups can be assigned to vocal clans based on their production of codas, short stereotyped patterns of clicks. It is currently unclear whether genetic variation could account for these behavioural differences. We studied mitochondrial DNA (mtDNA) variation among sympatric vocal clans in the Pacific Ocean, using sequences extracted from sloughed skin samples. We sampled 194 individuals from 30 social groups belonging to one of three vocal clans. As in previous studies of sperm whales, mtDNA control region diversity was low (π = 0.003), with just 14 haplotypes present in our sample. Both hierarchical AMOVAs and partial Mantel tests showed that vocal clan was a more important factor in matrilineal population genetic structure than geography, even though our sampling spanned thousands of kilometres. The variance component attributed to vocal dialects (7.7%) was an order of magnitude higher than those previously reported in birds, while the variance component attributed to geographic area was negligible. Despite this, the two most common haplotypes were present in significant quantities in each clan, meaning that variation in the control region cannot account for behavioural variation between clans, and instead parallels the situation in humans where parent-offspring transmission of language variation has resulted in correlations with neutral genes. Our results also raise questions for the management of sperm whale populations, which has traditionally been based on dividing populations into geographic ‘stocks’, suggesting that culturally-defined vocal clans may be more appropriate management units.
Riera, Amalis, James F. Pilkington, John K. B. Ford, Eva H. Stredulinsky, N. Ross Chapman (2019). Passive acoustic monitoring off Vancouver Island reveals extensive use by at-risk Resident killer whale (Orcinus orca) populations. Endang Species Res 39:221-234.
ABSTRACT
Two sympatric populations of fish-eating Resident killer whales inhabit the coastal waters of British Columbia, Canada: Southern and Northern Resident killer whales. These populations are listed under Canada’s Species at Risk Act (SARA) as ‘endangered’ and ‘threatened’, respectively. Relatively little is known about their habitat use outside of the sheltered waters along the east coast of Vancouver Island, especially during the winter. SARA requires the identification of critical habitat for these populations. High densities of Chinook salmon—their primary prey—are found around Swiftsure Bank, an area identified as potential critical habitat for Southern Residents. However, it is a difficult area to survey for whales using conventional small-boat approaches. Here, we used 2 yr of data collected from an autonomous acoustic recorder deployed at Swiftsure Bank from 2009-2011 to assess the year-round habitat use of this area by Resident killer whales. Overall, Resident killer whales were detected on 244 of 680 monitored days (36%). Southern Residents were heard in all months, with activity peaking during the summer. Northern Residents were also heard throughout the year, but were mostly detected in the spring and fall, which indicates the 2 populations may differ in their strategies for using this common foraging area. High levels of use by both of these populations highlights the importance of Swiftsure Bank to both, supporting the expansion of Resident killer whale critical habitat to include this site.
Full paper HERE.
Risch, D., Siebert, U. & Van Parijs, S.M. (2014). Individual calling behaviour and movements of North Atlantic minke whales (Balaenoptera acutorostrata). J. Acoust. Soc. Am. 128, November 2010. Behaviour. doi: 10.1163/1568539X-00003187.
ABSTRACT
Information on individual calling behaviour and source levels are important for understanding acoustically mediated social interactions of marine mammals, for which visual observations are difficult to obtain. Our study, conducted in the Stellwagen Bank National Marine Sanctuary (SBNMS), located in the Gulf of Maine, USA, used passive acoustic arrays to track North Atlantic minke whales and assess the sound production behaviour of individuals. A total of 18 minke whales were acoustically tracked in this study. Individual calling rates were variable, with a median intercall interval (ICI) of 60.3 s. Average source levels (SLrms ) for minke whales pulse trains ranged between 164 and 168 dB re 1 ìPa, resulting in a minimum detection range of 0.4–10.2 km for these calls in this urban, coastal environment. All tracked animals were actively swimming at a speed of 5.0 ± 1.2 km/h, which matches swimming speeds of migrating minke whales from other areas and confirms SBNMS as part of the migration route of this species in the Western North Atlantic. Tracked minke whales produced 7 discrete call types belonging to 3 main categories, yet no individual produced all call types. Instead, minke whales produced 2 multisyllabic call sequences (A and B) by combining 3–4 different call types in a non-random order. While 7 of the trackedindividuals produced calling pattern A, 10 whales used calling pattern B, and only 1 animal combined call types differently. Animals producing different call sequences were in acoustic range of one another on several occasions, suggesting they may use these sequences for mediating social interactions. The fact that the same calling patterns were shared by several individuals suggests that these patterns may contain information related to sex, age or behavioural context.
A PDF may be obtained from Behaviour or requests for reprints can be sent to: denise.risch@noaa.gov.
Samarra, Filipa I. P., Volker B. Deecke, and Patrick J. O. Miller. (2016). Low-frequency signals produced by Northeast Atlantic killer whales (Orcinus orca). J. Acoust. Soc. Am. 139, 1149 (2016).
ABSTRACT
Killer whale acoustic behavior has been extensively investigated; however, most studies have focused on pulsed calls and whistles. This study reports the production of low-frequency signals by killer whales at frequencies below 300?Hz. Recordings were made in Iceland and Norway when killer whales were observed feeding on herring and no other marine mammal species were nearby. Low-frequency sounds were identified in Iceland and ranged in duration between 0.14 and 2.77?s and in frequency between 50 and 270?Hz, well below the previously reported lower limit for killer whale tonal sounds of 500?Hz. Low-frequency sounds appeared to be produced close in time to tail slaps, which are indicative of feeding attempts, suggesting that these sounds may be related to a feeding context. However, their precise function is unknown, and they could be the by-product of a non-vocal behavior rather than a vocal signal deliberately produced by the whales. Although killer whales in Norway exhibit similar feeding behavior, this sound has not been detected in recordings from Norway to date. This study suggests that, like other delphinids, killer whales produce low-frequency sounds, but further studies will be required to understand whether similar sounds exist in other killer whale populations.
Full paper available for purchase HERE.
Samarra, Filipa I. P., Volker B. Deecke, Katja Vinding, Marianne H. Rasmussen, René J. Swift and Patrick J. O. Miller. (2010). Killer whales (Orcinus orca) produce ultrasonic whistles. J. Acoust. Soc. Am. 128, November 2010.
ABSTRACT
This study reports that killer whales, the largest dolphin, produce whistles with the highest fundamental frequencies ever reported in a delphinid. Using wide-band acoustic sampling from both animal-attached (Dtag) and remotely deployed hydrophone arrays, ultrasonic whistles were detected in three Northeast Atlantic populations but not in two Northeast Pacific populations. These results are inconsistent with analyses suggesting a correlation of maximum frequency of whistles with body size in delphinids, indicate substantial intraspecific variation in whistle production in killer whales, and highlight the importance of appropriate acoustic sampling techniques when conducting comparative analyses of sound repertoires.
Full paper HERE.
Saulitis, Eva L.; Matkin, Craig O.; Fay, Francis H. (2005). Vocal repertoire and acoustic behavior of the isolated AT1 killer whale subpopulation in southern Alaska. Canadian Journal of Zoology, Volume 83, Number 8, 1 August 2005 , pp. 1015-1029(15).
ABSTRACT
Killer whales, Orcinus orca (L., 1758), in the North Pacific are classified as three genetically distinct ecotypes: residents (fish-eaters), transients (mammal-eaters), and offshores (probable fish-eaters). Within the transient ecotype, three putative subpopulations have been identified by genetic analysis: West Coast transients, Gulf of Alaska transients, and AT1 transients. Here, we examine the behavior and vocalizations of the AT1 transients, which are found only in the Prince William Sound/Kenai Fjords region, to determine if their acoustic behavior distinguishes them from other genetically distinct transient subpopulations. We identified 14 discrete, pulsed calls in the vocal repertoire of the AT1 transients. These calls were ntirely different than those of West Coast and sympatric Gulf of Alaska transients. Despite their large call repertoire, AT1 transients were silent most of the time, utilizing a foraging strategy of stealth, acoustic crypsis, and passive listening for locating marine-mammal prey. Unlike resident killer whales, AT1 transient vocalization types were context specific. For example, lone AT1 transients produced long-distance, high-amplitude pulsed calls in stereotyped sequences to locate other AT1 whales. In contrast, hunting individuals emitted low-amplitude pulsed calls to maintain contact with group members. The repertoire and call-usage patterns of the AT1 transients are consistent with genetic evidence that they are a unique, reproductively and socially isolated subpopulation in danger of extinction.
Sayigh, L.S., P.L. Tyack, R.S. Wells, A. R. Solow, M.D. Scott, A.B. Irvine (1998). Individual recognition in wild bottlenose dolphins: a field test using playback experiments. Animal Behaviour, Vol. 57, p. 41-50.
Quote: "Overall, what is known of bottlenose dolphin behavior and social structure support the idea that individuals do have concepts of one another as individuals and that they track the history of their individual relationships."... "positive results, in the form of head turns towards the speaker, suggest not only that dolphins recognize their kin or associates, but also that they are motivated to respond to them." "...individually specific social relationships are important to dolphins."
Note: This study confirms that among dolphins, including orcas, individuals are recognized members of kinship groups. The question of whether a long-term captive orca such as Lolita would be recognized after a long absence from its family could be answered with a simple real time acoustic experiment even while in captivity, but the experiment has not been permitted by the management of marine parks.
Sharpe, Deborah L., Manuel Castellote, Paul R. Wade & Leslie A. Cornick. Call types of Bigg’s killer whales (Orcinus orca) in western Alaska: using vocal dialects to assess population structure.
ABSTRACT
Bigg’s killer whales (Orcinus orca; i.e. ‘transient’ ecotype), as apex predators, are important to the dynamics of marine ecosystems, but little is known about their population structure in western Alaska. Currently, all Bigg’s killer whales in western Alaska are ascribed to a single broad stock for management under the US Marine Mammal Protection Act. However, recent nuclear microsatellite and mitochondrial DNA analyses indicate that this stock is likely comprised of genetically distinct sub-populations. In accordance with what is known about killer whale vocal dialects in other locations, we used the spatial distribution of group-specific call types to investigate the population structure of Bigg’s killer whales in this part of Alaska. Digital audio recordings were collected from 33 Bigg’s killer whale encounters throughout the Aleutian and Pribilof Islands in the summers of 2001–2007 and 2009–2010. Recorded calls were qualitatively classified into discrete types and then quantitatively described using 12 structural and time-frequency measures. Resulting call categories were validated using a random forest approach. A total of 36 call types and subtypes were identified across the entire study area, and regional patterns of call type use revealed three distinct dialects which correspond to proposed genetic delineations. Our results suggest that there are at least three acoustically and genetically distinct sub-populations in western Alaska, and we present an initial catalogue for this area describing the regional vocal repertoires of Bigg’s killer whale call types.
Simon, Malene, Peter K. McGregor, and Fernando Ugarte. The relationship between the acoustic behaviour and surface activity of killer whales (Orcinus orca) that feed on herring (Clupea harengus). Springer Berlin/Heidelberg Volume 10, Number 2 / November, 2007.
ABSTRACT
We describe the acoustic behaviour of piscivorous killer whales in Norwegian and Icelandic waters. Whales were assigned to one of three activities (feeding, travelling or other), and sound recordings were made in their proximity with a single hydrophone and a digital audiotape (DAT) recorder. A quantitative analysis of the production of pulsed calls, whistles and echolocation clicks in the three activities revealed that there was a significant effect of activity on the production of these sound types. Both killer whales in Icelandic and Norwegian waters produced high rates of clicks and calls during feeding and low rates of click, calls and whistles during travelling. The differences can be used as acoustical markers and provides new possibilities for acoustic monitoring of killer whales in these areas. Based on the similarity between their prey choice, hunting strategies, phenotype and acoustic behaviour, we suggest that the killer whales in Icelandic and Norwegian waters belong to the same ecotype: Scandinavian herring-eating killer whales.
Keywords: Acoustic behaviour - Killer whale - Orcinus orca - Scandinavian waters
Simon, Malene, Magnus Wahlberg, and Lee A. Miller. Echolocation clicks from killer whales (Orcinus orca) feeding on herring (Clupea harengus) (L). J. Acoust. Soc. Am. 121 2, February 2007.
INTRODUCTION
Toothed whales Order: Odontoceti listen for echoes from their intense, brief echolocation clicks to find prey. There have been many studies on the biosonar of captive odontocetes, but our understanding of how these animals use echolocation in the field is limited (Au, 2002). Killer whales Orcinus orca specialize in a large variety of prey species in different parts of the world. The acoustic properties of their biosonar signals have been described for the NE Pacific resident killer whales that feed mainly on salmon Barrett-Lennard et al., 1996; Au et al., 2004. Comparing these data with those from other killer whale populations that feed on other prey species may reveal how the biosonar in this odontocete is adapted to different foraging situations and prey. Here we present the first acoustic analysis of full bandwidth hydrophone array recordings of echolocation clicks from wild killer whales foraging on Atlantic herring Clupea harengus.
Simon, Malene, Fernando Ugarte, Magnus Wahlberg, and Lee A. Miller. (2006). Icelandic killer whales (Orcinus orca) use a pulsed call suitable for manipulating the schooling behaviour of herring (Culpea harengus). The International Journal of Animal Sound and its Recording, 2006, Vol. 16, pp. 57–74.
ABSTRACT
Icelandic and Norwegian killer whales feed on herring, after debilitating them with underwater tail slaps. We analysed sound recordings of Icelandic and Norwegian killer whales engaged in feeding and other behaviour. We describe a pulsed call made by Icelandic killer whales shortly before underwater tail slaps, which had an atypical low frequency (average peak frequency: 683 ±131 Hz), long duration (3.0 ±1.1 s) and high intensity (source level 169-192 dB pp re 1 μPa @ 1 m). The low-frequency emphasis of this call was below the most sensitive hearing range of killer whales, suggesting that the call may not be optimal for interspecific communication. However, herring could easily perceive the killer whale call since the frequency content is similar to the resonant frequency of their swim bladder as well as to the most sensitive frequency band of hearing in this species. Previous studies have shown that sound may cause schooling herring to cluster. A high density of herring in a school would increase the effectiveness of the underwater tail slaps. We suggest that some Icelandic killer whales use this low-frequency call to herd herring into dense schools immediately before delivering an underwater tail slap, thereby increasing their foraging success.
Keywords: Killer Whale, Orcinus orca, vocalisations, tail slaps, Atlantic Herring, Clupea harengus.
Souhaut M, Shields MW. 2021. Stereotyped whistles in southern resident killer whales. PeerJ 9:e12085
ABSTRACT
The endangered Southern Resident killer whales (Orcinus orca) of the northeast Pacific region use two main types of vocal signals to communicate: discrete calls and whistles. Despite being one of the most-studied cetacean populations in the world, whistles have not been as heavily analyzed due to their relatively low occurrence compared to discrete calls. The aim of the current study is to further investigate the whistle repertoire and characteristics of the Southern Resident killer whale population. Acoustic data were collected between 2006–2007 and 2015–2017 in the waters around San Juan Island, Washington State, USA from boats and from shore. A total of 228 whistles were extracted and analyzed with 53.5% of them found to be stereotyped. Three of the four stereotyped whistles identified by a previous study using recordings from 1979–1982 were still occurring, demonstrating that whistles are stable vocalizations for a period of more than 35 years. The presence of three new stereotyped whistles was also documented. These results demonstrate that whistles share the longevity and vocal tradition of discrete calls, and warrant further study as a key element of Southern Resident killer whale communication and cultural transmission.
This publication is open-access and can be found at the following link:
Stereotyped whistles in southern resident killer whales [PeerJ]
Thomsen, F. Franck, D. and Ford, J.K.B. (2001). Characteristics of whistles from the acoustic repertoire of resident killer whales (Orcinus orca) off Vancouver Island, British Columbia. Naturwissenschaften Volume 89, Number 9 / September, 2002
ABSTRACT
Killer whales (Orcinus orca) use pulsed calls and whistles in underwater communication. Unlike pulsed calls, whistles have received little study and thus their function is poorly known. In this study, whistle activities of groups of individually known killer whales were compared quantitatively across behavioural categories. Acoustic recordings and simultaneous behavioural observations were made of northern resident killer whales off Vancouver Island in 1996 and 1997. Whistles were produced at greater rates than discrete calls during close-range behavioural activities than during long-range activities. hey were the predominant sound-type recorded during socializing. The number of whistles per animal per minute was significantly higher during close-range behavioural activities than during long-range activities. Evidently, whistles play an important role in the close-range acoustic communication in northern resident killer whales.
Full paper HERE.
Van Cise, Amy M., A Marie A. Roch, Robin W. Baird, T. Aran Mooney, Jay Barlow (2017). Acoustic differentiation of Shiho- and Naisa-type short-finned pilot whales in the Pacific Ocean. The Journal of the Acoustical Society of America > Volume 141, Issue 2 > 10.1121/1.4974858.
ABSTRACT
Divergence in acoustic signals used by different populations of marine mammals can be caused by a variety of environmental, hereditary, or social factors, and can indicate isolation between those populations. Two types of genetically and morphologically distinct short-finned pilot whales, called the Naisa- and Shiho-types when first described off Japan, have been identified in the Pacific Ocean. Acoustic differentiation between these types would support their designation as sub-species or species, and improve the understanding of their distribution in areas where genetic samples are difficult to obtain. Calls from two regions representing the two types were analyzed using 24 recordings from Hawai‘i (Naisa-type) and 12 recordings from the eastern Pacific Ocean (Shiho-type). Calls from the two types were significantly differentiated in median start frequency, frequency range, and duration, and were significantly differentiated in the cumulative distribution of start frequency, frequency range, and duration. Gaussian mixture models were used to classify calls from the two different regions with 74% accuracy, which was significantly greater than chance. The results of these analyses indicate that the two types are acoustically distinct, which supports the hypothesis that the two types may be separate sub-species.
Full paper available online HERE.
Veirs, Scott, Val Veirs and Jason D. Wood (2016). Ship noise extends to frequencies used for echolocation by endangered killer whales. PeerJ 4:e1657; DOI 10.7717/peerj.1657.
ABSTRACT
Combining calibrated hydrophone measurements with vessel location data from the Automatic Identification System, we estimate underwater sound pressure levels for 1,582 unique ships that transited the core critical habitat of the endangered Southern Resident killer whales during 28 months between March, 2011, and October, 2013. Median received spectrum levels of noise from 2,809 isolated transits are elevated relative to median background levels not only at low frequencies (20-30 dB re 1 mu Pa2/Hz from 100 to 1,000 Hz), but also at high frequencies (5-13 dB from 10,00 to 96,000 Hz). Thus, noise received from ships at ranges less than 3 km extends to frequencies used by odontocetes. Broadband received levels (11.5-40,000 Hz) near the shoreline in Haro Strait (WA, USA) for the entire ship population were ± 7 dB re 1 mPa on average. Assuming near-spherical spreading based on a transmission loss experiment we compute mean broadband source levels for the ship population of 173 ± 7 dB re 1 mPa 1 m without accounting for frequency-dependent absorption. Mean ship speed was 7.3 ± 2.0 m/s (14.1 ± 3.9 knots). Most ship classes show a linear relationship between source level and speed with a slope near +2 dB per m/s (+1 dB/knot). Spectrum, 1/12-octave, and 1/3-octave source levels for the whole population have median values that are comparable to previous measurements and models at most frequencies, but for select studies may be relatively low below 200 Hz and high above 20,000 Hz. Median source spectrum levels peak near 50 Hz for all 12 ship classes, have a maximum of 159 dB re 1 mPa2/Hz @ 1 m for container ships, and vary between classes. Below 200 Hz, the class-specific median spectrum levels bifurcate with large commercial ships grouping as higher power noise sources. Within all ship classes spectrum levels vary more at low frequencies than at high frequencies, and the degree of variability is almost halved for classes that have smaller speed standard deviations. This is the first study to present source spectra for populations of different ship classes operating in coastal habitats, including at higher frequencies used by killer whales for both communication and echolocation.
Full paper HERE.
Vergara, Valeria and Lance G. Barrett-Lennard (2008). Vocal Development in a Beluga Calf (Delphinapterus leucas). Aquatic Mammals 2008, 34(1), 123-143, DOI 10.1578/AM.34.1.2008.123.
ABSTRACT
Acoustic communication is central to the socioecology of cetaceans. Knowledge of the ontogeny of their extensive repertoires is scant, and even less is known about the role of learning in vocal development. To examine these issues, the development of calls of one male beluga (Delphinapterus leucas) calf was systematically studied at the Vancouver Aquarium throughout his first year of life and opportunistically through his second and third years. He vocalized within the first hour after birth, producing exclusively low energy, broadband pulse trains. Both the dominant frequency and the pulse repetition rate of the pulsed calls increased with age. He acquired rudimentary whistles at 2 wks of age. During the second month, whistle production increased substantially. Whistle dominant frequency tended to increase with age, and at least in his first year, whistles did not attain full stereotypy. The calf started using mixed call types consistently at 4 mo. While some sounds tended to be more variable at later ages, his mixed calls progressively lost variability and increasingly resembled his mother’s most predominant stereotyped mixed call type. By 20 mo, this call type was fully stereotyped. Six months after he was exposed to his father’s sounds, he incorporated one of his father’s call types into his repertoire. These findings are discussed in light of current theories of sound production mechanisms in odontocetes, developmental stages of vocal acquisition, and vocal learning.
Full paper HERE.
Weiss, Brigitte M., Friedrich Ladich, Paul Spong and Helena Symonds (2006). Vocal behavior of resident killer whale matrilines with newborn calves: The role of family signatures. J. Acoust. Soc. Am. 119 1, January 2006.
ABSTRACT
Studies of the vocal behavior of resident killer whales or orcas, Orcinus orca, in British Columbia have shown that matrilines have unique call repertoires consisting of up to 17 different call types. These call types cannot be attributed exclusively to specific behaviors, and their function in social contexts is poorly understood. This study investigated the change in call patterns of three resident matrilines in a changed social environment, before and up to one year after the birth of a calf. Acoustic data were collected with a network of hydrophones and were supplemented by visual observations. Call use changed distinctly after the birth of a calf in all three observed matrilines. All call types that were recorded in control situations were also recorded in postbirth situations; however, aberrant versions of discrete calls and excitement calls made up a higher proportion of calls after birth. Most conspicuously, family-specific call types occurred significantly more frequently in the days following a birth in two of the three matrilines and gradually returned to prebirth values within 2 weeks. Their increased use after a calf’s birth may facilitate the learning process of this "acoustic family badge" and thereby help to recognize and maintain cohesion with family members.
Wellard, R., Erbe, C., Fouda, L., Blewitt, M., (2015). Vocalisation of killer whales (Orcinus orca) in the Bremer Canyon, Western Australia. . PLoS ONE 10(9). DOI: 10.1371/journal.pone.0136535.
ABSTRACT
To date, there has been no dedicated study in Australian waters on the acoustics of killer whales. Hence no information has been published on the sounds produced by killer whales from this region. Here we present the first acoustical analysis of recordings collected off the Western Australian coast. Underwater sounds produced by Australian killer whales were recorded during the months of February and March 2014 and 2015 in the Bremer Canyon in Western Australia. Vocalisations recorded included echolocation clicks, burst-pulse sounds and whistles. A total of 28 hours and 29 minutes were recorded and analysed, with 2376 killer whale calls (whistles and burst-pulse sounds) detected. Recordings of poor quality or signal-to-noise ratio were excluded from analysis, resulting in 142 whistles and burst-pulse vocalisations suitable for analysis and categorisation. These were grouped based on their spectrographic features into nine Bremer Canyon (BC) "call types". The frequency of the fundamental contours of all call types ranged from 600 Hz to 29 kHz. Calls ranged from 0.05 to 11.3 seconds in duration. Biosonar clicks were also recorded, but not studied further. Surface behaviours noted during acoustic recordings were categorised as either travelling or social behaviour. A detailed description of the acoustic characteristics is necessary for species acoustic identification and for the development of passive acoustic tools for population monitoring, including assessments of population status, habitat usage, migration patterns, behaviour and acoustic ecology. This study provides the first quantitative assessment and report on the acoustic features of killer whales vocalisations in Australian waters, and presents an opportunity to further investigate this little-known population.
Full paper HERE.
Alternatively, if you are unable to download the article please email the author for a pdf at: becwellard@gmail.com.
Williams, Rob, Christine Erbe, Erin Ashe, Amber Beerman, Jodi Smith (2013). Severity of killer whale behavioral responses to ship noise: A dose–response study. Marine Pollution Bulletin http://dx.doi.org/10.1016/j.marpolbul.2013.12.004.
ABSTRACT
Critical habitats of at-risk populations of northeast Pacific ‘‘resident’’ killer whales can be heavily trafficked by large ships, with transits occurring on average once every hour in busy shipping lanes. We modeled behavioral responses of killer whales to ship transits during 35 ‘‘natural experiments’’ as a dose–response function of estimated received noise levels in both broadband and audiogram-weighted terms. Interpreting effects is contingent on a subjective and seemingly arbitrary decision about severity threshold indicating a response. Subtle responses were observed around broadband received levels of 130 dB re 1 lPa (rms); more severe responses are hypothesized to occur at received levels beyond 150 dB re 1 lPa, where our study lacked data. Avoidance responses are expected to carry minor energetic costs in terms of increased energy expenditure, but future research must assess the potential for reduced prey acquisition, and potential population consequences, under these noise levels.
Yurk, Harald (2005). Vocal culture and social stability in resident killer whales (Orcinus orca). Marine Mammal Research Unit, Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada.
ABSTRACT
The killer whale (Orcinus orca) is one of the few species for which vocal culture is actively involved in the development and maintenance of the social organizations of populations. In particular, the social structure of one form of killer whales, called residents, is a good example of this involvement. Resident societies are characterized by associations of groups with highly stable membership, which allow an in-depth examination of the association between vocal culture and the nested social hierarchy of that population. Resident killer whales live in small populations where inbreeding is a threat to their genetic diversity. Genetic and cultural evolution may be closely linked in killer whales, as has been proposed for a number of other cetaceans with matrilineal social structure. To test for a possible link between genetic and cultural evolution in killer whales, I investigated vocal similarities and differences among mixing and non-mixing resident groups and between two ecotypes, residents and transients.
First, I examined whether clans exist among resident killer whales in Southern Alaska. Vocal clans had been previously identified in British Columbia but not in Alaska. Two acoustically distinct clans were recognized, each of which was monomorphic for a different mitochondrial D-loop haplotype based on results of a separate genetic study. Thus, acoustic similarities within these cultural groups reflect common matrilineal ancestry, which suggests that clan-based social structure is a fixed characteristic of resident killer whales.
Second, I examined the similarity of vocal repertoires between residents and transients, and among clans and communities within residents. Call type similarity does not exist above the clan level. To investigate vocal similarity above the clan level, I split calls into syllables, and compared their distribution among population levels. Structural variation of upper frequency syllables characterized vocal variation among clans of the same community, while usage of distinct lower frequency syllables reflected divisions among communities and between residents and transients.
Third, I examined syntax, the ordered arrangement of syllables, among clans of resident communities. I found that vertical transmission of syllable order in matrilines is important for the distinctiveness of call type repertoires and leads to clan-specific syntax rules. Previous work has shown that mating mainly takes place between clans. Because syntax similarity appears to be negatively correlated with sociality among clans, resident killer whales may use syntax variation to choose mates with low levels of genetic relatedness.
The link between vocal culture and social structure likely influences mate choice in resident killer whales. This link leads t gene-culture co-evolution in killer whales and makes them excellent candidates for studies of cultural taxonomy.
Full paper HERE.
Yurk, Harald (2001). Parallel cultural and genetic lineages in Alaskan resident type killer whales. Marine Mammal Research Unit, Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada.
ABSTRACT
We present evidence that at least two acoustically and genetically distinct clans (vocally related pods) of resident killer whales inhabit Prince William Sound, Alaska. We compared the sound contours of approximately 9000 calls from 480 recording sessions of six photo identified killer whale pods. The pods fell into two acoustically distinct clans, with no evidence of sharing of call types between them. One clan referred to as AB-clan, included AB AI and AN pods. The second clan, AE-clan, included AD, AE and AK pods. We identified a mean number of 12 distinct call types for each pod, based predominantly on pulsed tone components. Call types and their variants were shared among member pods of the same clan. A dendogram based on a quantitative index of acoustical similarity shows that within AB-clan, AB, AI and AN pods are vocally more similar to each other than either is to AJ pod. Within AD-clan, AD, AE and AK pods are equally similar. Using DNA from biopsy samples, we sequenced the entire mitochondrial region control region of 16 AB-clan and 12 AE-clan individuals, including members of each pod. Each clan was monomorphic for a single haplotype and the two clans differed by one transition. It thus appears that the acoustic differences between the clans, which we presume to be cultural, are distinct clans (vocally related pods) of resident killer whales inhabiting Prince William Sound, Alaska.
Note: Yurk has found that the resident killer whales of Alaska have vocal traditions or cultural lineages that match maternal lineages as proposed by Dr. Ford earlier. This is the first time that direct evidence for the existence of parallel cultural and genetic lineages has been found in a non-human society.
Yurk, H., Barrett-Lennard, L., Ford, J.K.B., Matkin, C. (2002). Cultural transmission within maternal lineages: vocal clans in resident killer whales in southern Alaska. Animal Behaviour, 2002, 63, 1103–1119.
ABSTRACT
Cultural lineages are based on learned social traditions that are stable for several generations. When cultural lineages also reflect common ancestry and/or are shared by individuals that live together they are called clans. The existence of clans among killer whales has been previously proposed but has not been confirmed. Here, we show that clans exist among resident type killer whales, Orcinus orca, in southern Alaska. Resident killer whales live in stable matrilines from which emigration of either sex has not been observed. Matrilines that associate regularly (.50% observation time) are called pods. Pods are believed to consist of closely related matrilines and share a unique repertoire of discrete call types. Pods that share parts of their repertoire form what Ford (1991, Canadian Journal of Zoology, 69, 1454–1483) called an acoustic clan. Here, we identified discrete call types of seven pods from southern Alaska, using a method based on human discrimination of distinct aural and visual (spectrogram) differences. Mitochondrial DNA of members of each pod was also analysed. The repertoires of the seven pods were compared and two acoustically distinct groups of pods were identified. Each group was monomorphic for a different mitochondrial D-loop haplotype. Nevertheless, pods from different clans associated frequently. It thus appears that the acoustic similarities within groups, which we presume to be cultural, reflect common ancestry, and that these groups therefore meet the above definition of clans. We also argue that a combination of cultural drift and selection are the main mechanisms for the maintenance of clans.