by Clark Tate
A glossy black and white behemoth, the orca (Orcinus orca) inspires art and spawns legends that reflect a long and complicated history with man. Perhaps a shared trait sparks this endless fascination. Just like us, orcas, or killer whales, have spindle cells —neurons thought to be responsible for self-awareness, empathy, complex social structures, even love. Often found in cold coastal waters but ranging throughout the entire ocean, orcas live in socially complex, multigenerational, matriarchal pods of up to 40. Female orcas are among the few organisms on earth that experience menopause, so they live long after their fertile years; sons and daughters remain with mothers for life. A mother's presence seems to be especially important to the wellbeing of adult male orcas.
Breeding occurs in the late summer or early fall, when several clans join to form a “super pod.” The marine equivalent of a barn dance, sociable frolicking—breaching, spy hopping and tail lopping—abounds while males mingle among pods to find a mate before returning to their home pods. Pods have their own dialects.
Orcas are apex predators who hunt cooperatively with their pod, using echolocation as bats do to target prey. When hunting, orcas often ram their prey or, in the case of seals, toss it out of the water to whack it with their tails, preferring to stun the animal before sinking in their 4-inch-long teeth. The orca’s hunting prowess has earned it fierce nicknames such as ballena assasina (whale killer). That’s right, the killer whale—which is not actually a whale but the world’s largest dolphin—kills whales. In fact, you can thank them for many of Santa Cruz’s humpback whale sightings. Orcas stalk the deepwater canyon bisecting the bay to ambush humpbacks and grays from below as they migrate, forcing them toward Monterey Bay shorelines.
Orcas often feed on fish, squid, seabirds, marine mammals such as seals and sea lions, and have even been spotted attacking swimming deer and moose. But the food that an orca eats is largely determined by the type of orca it happens to be. There are four known types (resident, transient, offshore, or southern). Residents eat fish, transients eat marine mammals, and offshore species eat…sharks. At least they do in the northeastern Pacific, where they chow down on Pacific sleeper shark. Orcas have even taken down great whites for their livers alone.
All this food helps orcas to grow to a length of 23 to 32 feet and a weight of 4 to 8 tons. The most striking physical feature is their black, triangular dorsal fin slicing through the water, which can reach 6 feet on a mature male. A white eye patch and white chin and belly markings end in graceful curves on the flank. There is also a gray “saddle patch” behind the dorsal fin, which is handy in identifying individuals.
The size of most orca populations is unknown, though many pods are classified as threatened locally, such as the offshore orcas living between California and Alaska. The various orca types cannot replace one another, as they do not interbreed but are genetically distinct, hunt differently, and have different diets.
Most orcas live 50 to 80 years, though some reach their 90s, usually dying of old age, disease or poisoning by toxins such as DDT and PCBs. Events like the 1989 Exxon Valdez oil spill can devastate orca populations.
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