Killer Whale

Tail fluke

• black on top and white underneath – in males, the tips curve downwards

Surface behaviour

• in large groups, often surface in groups or in unison – aerial behaviours are very common (e.g. breaching, spyhopping, tail-lobbing, pectoral fin slapping)

Group size / social behaviour

• ranges from 2-5 (transients) to 5-30 (residents) to 30-80 (offshores) – groups may be spread out across a body of water

Can be confused with

• Dall’s porpoises sometimes mistaken as ‘baby’ killer whales
• False killer whale
• Risso’s dolphin or Pacific white-sided dolphin from a distance

Natural History

Killer whales along the coast of British Columbia and Washington are some of the best-studied whales in the world. Intensive field research in this region has been in progress for almost 30 years.In the early 1970’s photo-identification of killer whales was established by the late Michael Bigg of Fisheries and Oceans Canada.This technique was integral in allowing researchers to identify individual killer whales and by extension estimate population sizes, movement patterns and provide insight into social structure and birth and death rates. Photo identification is a technique that is undertaken to this day; identification catalogues are continually being updated by Fisheries and Oceans Canada and the Center for Whale Research.  However, while these studies have increased knowledge about these whales they also illustrate how much remains to be learned.

There are three types of killer whales that live in the waters off the coast of western North America. These three assemblages have distinct differences in their diet, range, behaviour and social systems.

Resident killer whales

Resident killer whales range from SE Alaska down to the coast of Oregon, although in recent years some of the pods have been seen as far south as California in the winter months. Resident killer whales are salmon specialists, and chinook salmon makes up the majority of their diet, year-round. These whales rely on echolocation to find their prey.

Resident killer whales live in a complex matriarchal society, in which sons and daughters with their mother throughout their lives, even after they have offspring of their own. These bonds remain strong between siblings even after the mother has died. In the resident assemblage, these family units are known as MATRILINES. A pod is a larger unit that is made up of one or more matrilines that travel together and may be related. A clan is a group of pods that share similar calls or dialects, indicating that they share a common ancestry and a more closely related to each other than to whales in other clans.

Resident killer whales appear to be split into two communities, which are known as “Southern” and “Northern” residents. In over 30 years of research, members of the two communities have not been found in the same area at the same time.

The southern resident community consists of one clan (J clan) and 3 pods (J, K and L pods) and number only 75 animals. They are most commonly seen in the waters around Victoria and the San Juan Islands in the summer, although they may range north to Desolation Sound and as far south as California in the winter months. Southern resident killer whales are critically endangered, due to their small population size, reliance on endangered or threatened salmon runs for prey, high toxin loads and sensitivity to boat disturbance.

The northern resident community consists of 3 clans (A, G and R) and numerous pods within each clan. It numbers approximately 300 animals. Northern residents are most commonly seen in the waters around the northern end of Vancouver Island, and in sheltered inlets along B.C.’s Central and North Coasts. They also range northward into Southeast Alaska in the winter months. Northern resident killer whales are also threatened by the same factors as southern residents.

Bigg’s (transient) killer whales

Bigg’s killer whales were formerly known as ‘transients’.  In 2012, a push was made to rename this type of killer whale in memory of Dr. Michael Bigg.  Bigg’s killer whales range all along the west coast of North America, from California to Alaska. They are mammal-eaters, specializing on smaller marine mammals such as seals, sea lions, porpoises, dolphins, and occasional calves or juveniles of larger species such as grey whales and humpback whales. In fact, the term “killer whale” is derived from this type of killer whale, which is the only species of whale that kills other whales.

Bigg’s killer whale societies are based on a matriline structure, similar to resident killer whales, but offspring may disperse from their mothers once they reach maturity, especially females once they’ve had calves of their own.

For Bigg’s, traveling in smaller groups is important to be able to efficiently hunt and catch their prey. Unlike fish, marine mammals can hear very well underwater, so Bigg’s killer whales vocalize and echolocate very rarely while searching for their prey. Instead, they follow the coastline, checking each cove for unsuspecting prey and use passive listening to locate seals and small cetaceans. Bigg’s typically vocalize either during or directly following a kill.

Offshore killer whales

Very little is known about offshore killer whales because they tend to spend most of their time offshore along the continental shelf. Some groups have been sighted in inshore waters and even deep into coastal inlets. Offshore killer whales are typically encountered in groups of 30 – 70 whales or more. Little is known about their social structure.

It is thought that these killer whales eat large ocean fish such as sharks and halibut. Compared to transient and resident killer whales, offshore killer whales have a large proportion of nicks and scarring, possibly from catching sharks. The few offshore killer whales that have stranded had teeth that were significantly worn down, which would also occur from consuming sharks which have very tough skin.

Offshore killer whales are acoustically distinct from resident and transient killer whales, but little is known about how they use their calls and how this differs from resident and Bigg’s killer whale behaviour.

For more information about killer whales in B.C., please visit Ocean Wise’s Wild Killer Whale Adoption Program.

The populations of killer whales in British Columbia have been assessed at various levels of risk by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).

Southern resident killer whale: Endangered (November 2008)

Northern resident killer whale: Threatened (November 2008)

Transient killer whale: Threatened (November 2008)

Offshore killer whale: Threatened (November 2008)

Publications

Au, W.W.L., J.K.B. Ford, J.K. Horne and K.A. Newman Allman. 2004. Echolocation signals of free-ranging killer whales (Orcinus orca) and modeling of foraging for chinook salmon (Oncorhynchus tshawytscha). Journal of the Acoustical Society of America 115(2):901-909.

Baird, R.W. and H. Whitehead. 2000. Social organization of mammal-eating killer whales(Orcinus orca): Group stability and dispersal patterns. Canadian Journal of Zoology 78(12):2096-2105. [PDF]

Baird, R.W. and L.M. Dill. 1997. Ecological and social determinants of group size in transient killer whales. Behavioral Ecology 7(4): 408-416. [PDF]

Baird, R.W. and P.J. Stacey. 1988. Variation in saddlepatch pigmentation in populations of killer whales (Orcinus orca) from British Columbia, Alaska, and Washington State. Canadian Journal of Zoology 66: 2582-2585. [PDF]

Baird, R.W. 2001. Status of killer whales, Orcinus orca, in Canada. Canadian Field-Naturalist 115(4):676-701. [PDF]

Baird, R.W., M.B. Hanson, and L.M. Dill. 2005. Factors influencing the diving behaviour of fish-eating killer whale(Orcinus orca): Sex differences and diel and interannual variation in diving rates. Canadian Journal of Zoology 83(2):257-267. [PDF]

Barrett-Lennard, L.G. and K. Heise. 2007. The natural history and ecology of killer whales: Foraging specialization in a generalist predator. In Estes, J.A., Brownell, R.L., DeMaster, D.P., Doak, D.F., Williams, T.M. Whales, whaling and ocean ecosystems. University of California Press, Berkely, C.A.

Barrett-Lennard, L.G., J.K.B. Ford, and K.A. Heise. 1996. The mixed blessing of echolocation: differences in sonar use by fish-eating and mammal-eating killer whales. Animal Behaviour 51: 553-565.

Bigg, M.A., P.F. Olesiuk, G.M. Ellis, J.K.B. Ford, and K.C. Balcomb III. 1990. Social organization and genealogy of resident killer whales (Orcinus orca) in the coastal waters of British Columbia and Washington State. Report of the International Whaling Commission: 383-405.

Deecke, V.B., J.K.B. Ford, and P Spong. 2000. Dialect change in resident killer whales (Orcinus orca): Implications for vocal learning and cultural transmission. Animal Behaviour 60(5): 619-638.

Deecke, V.B., J.K.B. Ford, and 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 105(4): 2499-2507.

Deecke, V.B., J.K.B. Ford, and P.J.B. Slater. 2005. The vocal behaviour of mammal-eating killer whales (Orcinus orca): Communicating with costly calls. Animal Behaviour 69: 395-405.