Orcas, also known as killer whales or blackfish, are the largest members of the dolphin family, and are considered apex predators at the top of the marine food chain. They feast on seals, sea lions and even other whales, thanks to sharp teeth that measure up to four inches in length. They are proficient hunters, and can grab seals right off the ice. They also eat fish, squid and seabirds.
Though they frequent cold coastal waters, killer whales are found worldwide from the polar regions to the equator. They’re renowned for their complex and stable social structures. Resident orcas in the Pacific Northwest are matrilineal, and pods can contain several matriarchs and up to four generations. Resident males always mate with females from other pods.
There appear to be at least three types of killer whale (pending a full scientific review): resident pods who prefer fish and squid, smaller groups of transients who target marine mammals, and offshore populations who feed primarily on schooling fish plus the odd sea mammal or shark. All orcas use efficient, cooperative hunting techniques that earn them the nickname ‘wolves of the sea.’
They are also skilled communicators, making underwater sounds for orientation, navigation and feeding. Our resident groups appear more vocal than their transient counterparts, each pod having an identifiable dialect common to a matriline. Orca whale vocalizations reflect a sophisticated and nuanced language that builds group identity and maintains equitable relations between pods.
Orcas are protective of their young, and other adolescent females often assist the mother in caring for them. Mothers give birth every three to ten years, following a 17-month pregnancy.
Orca whales are immediately recognizable by their distinctive black and white colouring, and the shape and height of their dorsal fins. They are the intelligent, trainable stars of many an aquarium show, a practice that is coming under scrutiny the more their complex social life and familial relationships are understood. Fortu-nately, orcas have rarely been hunted by humans, although human activities like shipping, drilling, and fish farming exact a toll on their well being.