This information about killer whales is intended only to cover those aspects of the animals’ biology not covered clearly in the published literature or for which there is conflicting information. It is based on the latest research conducted by Dr. Lance Barrett-Lennard, of the Vancouver Aquarium, and other cetacean biologists working on the coast of B.C., as well as the best data available from other areas.

How can I identify a killer whale?

• Killer whales are distinctively marked black-and-white dolphins. They exist in British Columbia as three distinct assemblages (groups): residents, transients and offshores.
• Each assemblage ( has major differences in behaviour and social organization, and subtle differences in appearance such as the back (dorsal) fins and saddle patches.
• Resident killer whales specialize in hunting salmon. They primarily hunt chinook, but chum salmon are also eaten during the fall. The residents’ social organization is based on small mother-led (matrilineal) groups called pods, which can include three to fifteen individuals.
• Transients are marine mammal “specialists,” preying on harbour seals, sea lions, elephant seals, porpoises and baleen whales such as minke whales and gray whale calves. Unlike residents, transients may leave their mother’s group around the time they mature.
• Offshore killer whales are poorly known, but tend to travel in groups of 30 to 60 individuals, probably preying on large oceanic fish such as sharks and halibut.
• Individual killer whales are commonly identified by patterns in the grey saddle patch located immediately behind the dorsal fin, and by natural markings (scars, nicks, etc.) on the dorsal fin itself.
  

How do killer whales reproduce?

• Some females give birth to their first calf at age 12, but most give birth at age 14-15.
• Usually single young are born; there is one documented case of twins in B.C.
• Length of pregnancy (gestation period) in aquarium killer whales has been recorded at close to 17 months.
• The maximum calving rate is one every three years.
• Females stop giving birth at approximately 40 years of age.
• Calves nurse from their mothers for at least one year, and sometimes up to 2 or 3 years.
  

How long do killer whales live?

• Field studies in B.C. suggest that males live to a maximum of 55 years while females may reach 70-80 years of age.
  Average life expectancy is estimated at about 30 years for males and 50 years for females.
  

Where do we find killer whales, and how many are found in British Columbia?

• Residents are only common on the coast from April to November, but some pods have been seen in inshore waters throughout the year. Some may go offshore or into mainland inlets during the winter. During the summer months, southern resident pods are commonly seen in Haro Strait and the San Juan Islands, and northern residents are often seen in the Johnstone Strait area.
  Transients are found along the B.C. coast year-round, and are constantly on the move in search of their prey.  They are often found in areas where seals are abundant. A transient pod may range up to 1,500 km along the coast from Alaska to California; resident pods have been known to travel up to 2,200 km!
  
  

How many killer whales are there in BC?

• There are approximately 300 northern and southern residents and 225 transients in B.C./Washington waters. At least 200 offshore killer whales have also been identified.
• The SE Alaska resident population is just over 300 killer whales, and there are numerous other populations of transient killer whales in California and Alaska that are distinct from local populations.

How do killer whales pass the time?

• Activities of both residents and transients can be grouped into four major categories: looking for food (foraging), resting, socializing and travelling. All of these seem to happen both day and night.
• Foraging is the most common activity, comprising about 60 percent of their daily activity. Resident pods in B.C. forage cooperatively and prey is often shared between individuals, particularly between mature females and juveniles. Mature males may sometimes hunt and eat independently from the rest of their group.
• Members of transient pods cooperate to chase, corner and kill their prey, and share their kill with group members.
  When resting, pod members slow down, group together tightly, become mainly silent and dive synchronously for 4-5 minutes or longer. Resting episodes usually last 2-3 hours.
• Socializing consists of sexual interactions and play among pod members. Beach rubbing is a traditional social behaviour among some northern resident pods.
  
  

What behaviours are killer whales commonly observed to perform?

• Sticking their head out of the water (spyhopping) and Aerial displays, such as breaching, tail slapping, dorsal-fin slapping, are most commonly seen during socializing episodes. These behaviours may represent play, but may also occur in other contexts such as foraging.
• Spyhopping seems to be a way of looking at the whales' surroundings; killer whales often spyhop when boats approach closely.
• Aerial behaviours are most likely displays of social excitement, dominance, or aggression.
  Transients may breach to startle or confuse prey, and
  tail-slap to stun or injure prey.
  

How do killer whales communicate?

• On average, each resident pod has a repertoire of 12 separate types of calls. All members of a pod will use all the calls.
• These calls are heard whenever the animals are active.
• Calls do not seem to have specific meanings, e.g. like nouns and verbs in human language, but may be used in different contexts.
• In most pods, some calls are unique to the group, while others are shared with other pods. Shared calls usually have pod-specific "accents."
• Pods with similar dialects form a "clan." Clan members have probably descended from a common ancestral group.
  Different clans often occur in the same area and pods from each clan may travel together.
• Pod-specific dialects probably convey information about pod relationship and are important in maintaining the cohesion and identity of the group.
• Slight changes to standard call formats communicate additional information such as the identity, location and emotional state of the vocalizing individual.
  

Key facts:

• Newborns are around 2 m long and weigh approximately 150 kg.
• Adult males can reach 9.8 m and 10,000 kg; females reach 8.5 m and 7,500 kg.
• The dorsal fin of males is approximately 1.7 m tall; females 1 m tall
• Side (pectoral) flippers of males may reach 2.5 m long and are much broader than those of the females.
• Top speed during travel or when chasing prey is roughly 45 km/h.
• Typical dive times are less than five minutes; the maximum recorded locally was 15 minutes, in a transient pod.
• The maximum dive depth is unknown; killer whales in B.C. are unlikely to dive very deep as their prey is usually found in the top 100 m of the water.
  

Did you know?

• Tail flukes of mature males curl downward, unlike those of females.
• A few mature males in the wild in B.C. and Alaska have bent dorsal fins.
• Like most other dolphins, killer whales have well developed eyesight (both above and below the water).
  

How Can I Adopt A Killer Whale?

• How can I help with killer whale research in British Columbia?
• If you see a whale or dolphin off the coast of British Columbia, we would love to hear about it. Report your sighting at http://www.wildwhales.org.

References:

1. American Cetacean Society. 2007. Orca Fact Sheet. (http://www.acsonline.org/factpack/KillerWhale.htm)
2. Barrett-Lennard, Lance G., and Graeme M. Ellis. 2001. Population structure and genetic variability in northeastern Pacific killer whales: towards an assessment of population viability. Canadian Scientific Advisory Secretariat, Department of Fisheries and Oceans Research Document 2001/065.
3. Ford, John K.B., Graeme M. Ellis, and Kenneth C. Balcomb. 2000. Killer Whales: A Study of their Identification, Genealogy, and Natural History in British Columbia and Washington State. Second edition. Vancouver: UBC Press.
4. Ford, John K.B. and Graeme M. Ellis. 1999. Transients: Mammal-Hunting Killer Whales of British Columbia. University of Washington Press.

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