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Endangered Species

Killer Whale or Orca

Killer Whale Photo

Scientific Name: Orcinus orca

Description: The Killer Whale is the most widespread and one of the most recognized mammals in the world. It is found in all the oceans from the Arctic to Antarctic, and tropical seas and open oceans. However, it is most often encountered in nearshore biologically rich areas and it occasionally enters estuaries and small bays. The Killer Whale has distinctive black and white markings with a prominent dorsal fin. The dorsal fin is from 1.0 to 1.8 meters tall in adult males and less than 0.7 meters in adult females. The head is rounded with a slight beak. Males can reach as long as 9.75 meters and females reach 8.53 meters.

Behaviour: Killer Whales usually travel in small groups known as pods. The average pod size for resident whales (see definition below) is about 12 individuals but up to 59 whales has been recorded. Transient pods range from one to four individuals. Single individuals, usually males, are occasionally encountered. The social group is matrilineal consisting of whales from two to three generations. Membership in the pod is stable although individuals will switch pods on occasion. Non-breeding females and males care and teach hunting methods to older calves of females with young calves.

More Killer Whale Behaviour

Breaching is the term that refers to the leaping out of the water to fall on the side with a big splash. Spyhopping is the vertical emergence of the whales head and part of its torso from the water. Tail lobbing occurs when a whale turns on to its belly and slaps the water surface with the top of its tail flukes while swimming upside down. Flipper slapping occurs when a whale turns on to its side and slaps the surface water with its fin. Killer Whales can dive for up to 17 minutes to a depth of at least 260 meters.

Hunting is often done in cooperative groups. Whales gather in narrow passages where salmon returning to spawning rivers are numerous such as in Johnstone Strait on northern Vancouver Island, and Haro Strait near Victoria, British Columbia. Transients hunt marine mammals by stealth often catching seals off guard in the water or by drowning sea lions and small whales.

Biology: In North America’s Pacific Northwest, Killer Whales have been categorized as residents and transients, although these are inaccurate descriptions of site use and their movements. Characteristics which differ between the two types of whales include the shape of the dorsal fin, pigmentation of the saddle patch, mitochondrial and nuclear DNA, diet, travel patters, respiration patterns, vocalizations, group size seasonal occurrence and geographic range. Residents eat mostly fish and transients specialize on a marine mammal diet. Resident and transient whales do intermingle socially, but there is some indication that the DNA of the two groups is sufficiently distinct to identify them as separate groups.

In the Pacific Northwest, resident Killer Whales are often referred to as belonging to southern, northern and offshore groups. The southern resident community is found generally around southern Vancouver Island and in Puget Sound. The northern resident community is found from northern Vancouver Island to southeast Alaska. The offshore community appears to inhabit the continental shelf break along the entire northwest coast, although information is scant.

Birth occurs between October and March in the northeastern Pacific. Females first give birth at about 15 years of age, gestation is about 17 months long and young calves are born about every 5 to 6 years. Calves remain dependent on their mothers for about two years and Killer Whales can live for at least 35 years in the wild.

Status: The southern resident population of Killer Whales were listed as endangered and the northern residents and transients were listed as threatened in November 2001 by the Committee on the Status of Wildlife in Canada.

Conservation: Attempts have been made to measure the impact of whale watching among whales near in Johnstone Strait and southern Vancouver Island and in Washington with mixed results. The validity of reported behavioural shifts in response to approaching boats is questioned by some researchers. Nonetheless, southern whales appear to spend less time resting.

Killer Whale Distribution Map

For more information: Baird, R.W. 2001. Status of Killer Whales, Orcinus orca in Canada. Canadian Field-Naturalist 115: 676-701; Wilson, D.E. and S. Ruff (eds.). 1999. The Smithsonian Book of North American mammals. University of British Columbia Press, Vancouver.

Killer Whale Pictures

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