Orcas of the Salish Sea
Part II
By 1990 researchers had established that female orcas average over fifty years longevity and can live for eighty or more years in the wild, while males average around thirty years and may live to around fifty or sixty (see Orca Lifespans for a more detailed discussion of how long orcas live). A great deal of experience and knowledge may reside in orcas of advanced years, and is passed down through generations. Female orcas and humans along with few, if any, other mammals, live 3 or 4 decades after their reproductive years. This "post-menopausal" lifespan is believed to be crucial to maintaining cultural values and traditions. As with humans, the wisdom of the elders is essential for the stability and well-being of the entire community.
The Social Life of the Orca
Some of the most interesting questions about orcas concern their social and cultural behaviors. Each community so far studied shows tremendous originality in their habits and social systems. Their diets, feeding strategies, patterns of movement, and of course their communication systems, vary widely between communities. Cetologists are just beginning to look at the differences in cultural adaptations between orca populations, and are coming to the realization that we are dealing with mammals that are capable of culture in the form of traditions and rules of behavior, much like us, and that meaningful communication may guide their behavior. According to a recent paper called Culture in whales and dolphins, published in the Journal of Behavioral and Brain Sciences: "The complex and stable vocal and behavioral cultures of sympatric groups of killer whales (Orcinus orca) appear to have no parallel outside humans and represent an independent evolution of cultural faculties."
There are probably less than 50 distinct orca communities worldwide, with the total number of individuals only about 30,000, some of which are tentatively classified as either residents (fish-eaters) or transients (mammal-eaters). All orcas travel over fairly large areas, but residents tend to frequent a specific territory and return with some regularity to the same areas. Resident pods usually include ten to twenty individuals and are known to eat only fish. As results emerge from studies of orca communities around the globe new surprises are sure to follow.
Like resident communities, transients sometimes come together to form large groups of up to twenty or more. Aggression toward other orcas is extremely rare among orcas of either type. They seem to truly enjoy their time together. Lifelong fidelity of offspring allows long-term stability and continuity of behavior.
Yet another community of orcas, believed to number around 300, was discovered in 1991. Known as Offshores, these whales are usually found in groups of from 15 to 75, along the coastal Pacific waters of North America from California to the Aleutian Islands. Little is known about their behavior or association patterns, but like every other community so far studied, offshores share a distinct repertoire of discrete calls, completely unlike those recorded from other communities. Their diet appears to consist mainly of sharks, especially sleeper sharks.
Orca Consciousness
Like all marine mammals, orcas have brought their breathing under conscious command. Orcas and other whales and dolphins rest by relaxing one hemisphere of their brain while guiding their swimming and breathing with the other half, often while swimming slowly in tight family groups. Orca brains are enormous, about 5 times the size of human brains, with a highly developed and convoluted neocortex, responsible for sophisticated cognitive processes. Consciousness correlates with the degree of complexity in the nervous system, and the structural complexity of the orca brain appears capable of supporting a degree of consciousness that could allow culturally acquired, meaningful communication.
Language?
A unique vocal repertoire is used by each orca community. Within communities, pods and matrilines make a few of their own distinct calls, known as dialects. Unlike some dolphin species, no "signature whistle" has been found in orcas. Every member of any given pod or matriline uses the same set of calls, and the majority of calls are shared with the whole community. Given that there are significant differences in behavior and in vocal repertoires from community to community, linguistics is highly correlated with group behavior. That indicates the behavior is guided by the vocalizations, so cultural rules for behavior are probably communicated by vocal expressions. Those rules appear to determine cultural traditions such as diets and mating patterns, and lifetime group cohesion.
Of course orcas need to successfully find food and reproduce, so ecological or energy considerations are crucial. Those requirements are accomplished as a group, through cultural traditions. Sometimes essential problems may not seem successfully solved (at least from a human vantage point), as in mass strandings or reliance on a specific food source, but a decision-making process is followed by the entire group, with vocalizations playing a key role. Overall, it appears orcas use a communication system we might as well call language.
According to reports from marine parks, ovulation is quite unpredictable among female orcas. Once the 72-day cycle begins it follows a normal mammalian course of events, but the onset of the cycle is independent of any external factors, including presence of a male, other females, temperature, food intake or annual seasons. This indicates the possibility that conception may be a matter of conscious choice. In the wild, such a choice may be subject to social controls, but in captivity trainers impose new demands, which may help explain why captive females often give birth at much younger ages than tradition-bound, free-ranging orcas.
A New View of the Orca
Over the past 50-plus million years the order Cetacea has filled the seas with over 80 species of whales, dolphins and porpoises, each radiating into its own ecological niche, together forming a complex and harmonious diversity. Some, like the blue whale, have grown extremely large while other species shrank to just a few feet long. Some adapted to foraging in shallow seas and even fresh water, and some learned to dive and find sustenance in the deep abyss. Whether in warm seas or cold polar regions, having teeth or gigantic filter-sieves to strain plankton from the currents, each species has survived by specializing to use an unexploited niche, rather than challenging and conflicting with one another.
Each orca community has followed that pattern by specializing on specific prey, apportioning available resources between communities, thereby avoiding competition and conflict.
Long ago the ancestors of the Southern resident community specialized their diet to devour only fish, primarily Chinook salmon, rather than seals or sea lions. With up to forty members in each pod, and a tendency for all three pods to gather together in "superpod" events, Southern community orcas depend on runs of Chinook streaming into the Salish Sea and milling at the mouths of rivers, each exquisitely adapted to its own seasonal niche in its natal stream and river. Historically there were always plenty of salmon in huge runs, providing year-around sustenance for the orcas, but now only a few chinook stocks of significant size return to spawn, and the orcas appear to be going hungry for much of each year.
Resident orcas now share their range with over 5 million industrial age humans, a dramatic increase in two centuries from about 200,000 native people who inhabited the region for thousands of years.
The fate of our local orcas, and all other killer whales around the globe, is inextricably linked to the health of marine ecosystems. These intelligent and resourceful creatures will do well as long as the basic food supply on which they depend is available. Orcas are at the top of the food chain so all the other sea creatures from krill to sea lions must prosper if the orcas are to survive. Here in Washington State and British Columbia, marine water quality and healthy salmon runs are crucial to the presence and survival of the Southern residents as well as the transients.
According to Dr. Bernard Shanks, former director of the Washington Department of Fish and Wildlife, if we restore our watersheds, we will create the conditions needed not only for salmonids, but the entire wild community, including orcas. Watershed habitat, including mountainsides of deep forests and clear streams, must be viable for a wide range of plants and animals including large populations of spawning salmon. Without year around abundance of salmon, the Southern resident orca community will likely vanish. If we care responsibly for our natural environment in the years to come, our lives will continue to be enriched by knowing that we share this watershed habitat with the magnificent and mysterious orca.
