Killer whales are found all over the world and live in communities that are totally separate from one another. These ten distinct populations are referred to as “ecotypes”, with five types residing in each hemisphere. This week we will explore the five ecotypes that call the Northern Hemisphere home!
Here in the Salish Sea we get to see two out of the five types – Resident and Bigg’s!
To read about their cousins in the Southern Hemisphere, click here.
1. Resident Orca – The Social Butterflies
Found between southeastern Alaska and northern California, residents are salmon specialists and can be recognized by the black openings in their saddle patches. Residents are known for their strict social structures and exceptionally chatty behaviour. They even have distinct accents and dialogues within their language! These killer whales form extended family groups called pods and follow a matriarch (usually an elder female). They are prone to acrobatic social displays, so if you are lucky enough to spot resident killer whales you may just catch a few breaches and tail slaps! Resident orcas are the most studied killer whales in the world, and the Center for Whale Research has studied the southern clan for more than 40 years.
2. Bigg’s (Transient) Orca – The Porpoise Crushers
Bigg’s killer whales inhabit the same geographic range as the Residents; however, they do not interact with each other. In fact, science tells us the two types have not interbred for over 700 000 years! Their name (Bigg’s) comes from the killer whale researcher, Dr. Michael Bigg, who discovered that individual orcas could be identified through photos of their dorsal fins. They live in small family groups (2-8 whales) and chase down their unsuspecting prey in silence. Unlike their resident cousins, Bigg’s killer whales are not highly conversational, and silence allows them to sneak up on their prey successfully. These stealthy hunters mainly go for mammals, like seals, sea lions, and porpoise. Occasionally during a porpoise attack they will punt them several meters out of the water before finally consuming them! They are known to have an ambitious appetite and even enjoy the odd minke whale or moose massacre.
3. Offshore Orca – The Toothless Wonders
As their name suggests, these killer whales are found offshore in the Pacific Northwest. There is still a lot to learn about this ecotype, because most researchers and whale watchers spend more time close to land. They travel in large groups of up to 200 whales, and mainly hunt sharks to eat their fatty livers.
But being a shark eater isn’t easy, and getting past their abrasive skin leads to a major consequence. Sharkskin is made of tiny teeth-like scales called “denticles”, so by the time the whales reach maturity (around age 15) their teeth get worn down to the gum-line. Therefore, how they hunt after this point is still a mystery, but it is unlikely that they can gum the sharks to death.
4. Type 1 Eastern North Atlantic Orca – The Fish Herders
Often found in the waters off Norway, this ecotype specializes in preying on small fish like herring and mackerel. Working together, they herd the fish into dense schools to pick them off more easily. Much like the offshore killer whales, some have been found with their teeth worn to the gums, therefore they are also thought to prey on sharks. They are the smaller of the two types of eastern north Atlantic killer whales, measuring no more than ~6.6 metres.
5. Type 2 Eastern North Atlantic Orca – The Whale-Eating Whales
Like Bigg’s orcas, these whales feast on mammalian meat, but with an affinity for other dolphin species and minke whales. They do not demonstrate the same tooth decay as their Type 1 counterparts, and probably eat no fish at all. These killer whales are a little-known ecotype, with only a few recorded observations. They are recognized by their back-sloping eye patch and their large size (up to 8.5 metres).
Feature Photo: Lili Wilson