The killer whale, or orca, is the largest member of the dolphin family, easy to recognize by its black-and-white body and white eye patches. In the US it is best known along the West Coast, where the fish-eating Southern Resident population of the Pacific Northwest is listed as endangered.
Appearance
- Appearance
- Mostly black on top and white below, with a white oval patch behind and above each eye and a gray or white "saddle" behind the dorsal fin. Adult males are typically 20–26 ft (6–8 m) long and females 16–23 ft (5–7 m); the largest males reach about 32 ft (9.8 m). Males have much taller dorsal fins and larger flippers than females.
- Voice
- Uses clicks, whistles, and pulsed calls. Each pod has its own set of calls that works like a family badge. Mammal-hunting orcas tend to stay quiet so prey won't hear them.
Look-alikes
False killer whalePseudorca crassidens
False killer whales are dark gray to black all over, with no white eye patches or saddle, and have a slender body and a small, cone-shaped head with no beak.
Why they get mixed upSimilar name and both are large, dark members of the dolphin family.
Where it lives
- Typical habitats
- Open ocean
- Coastal waters
- Range
- Found in every ocean. In the US, orcas are best studied along the West Coast from California to Alaska; Southern Residents range from central California to Southeast Alaska. They also occur in the Gulf and the North Atlantic off the Southeast US.
- Preferred conditions
- Prefers cooler coastal waters, but also lives in warm seas.
Behavior
- Diet
- Each population has its own learned menu. Residents eat mainly fish, especially salmon; Bigg's (transient) orcas hunt seals, sea lions, and porpoises; offshore orcas eat fish, including sharks.
- Social life
- Lives in pods of a few to 20 or more related whales. Resident orcas stay with their mothers for life. Pods often hunt cooperatively.
Life cycle
- Gestation
- About 15 to 18 months; there is no set calving season.
- Litter size
- Usually a single calf, which nurses for at least a year.
- Time to maturity
- Females mature at about 10 to 13 years. Killer whales are one of the few animals known to go through .
- Lifespan
- Females usually live about 50 years (up to at least 90); males about 30 years (up to at least 60).
Name and classification
- About the name
- Orcas are treated as one species, but scientists have long debated splitting them. A 2024 study proposed that the Pacific Northwest's fish-eating Residents and mammal-eating Bigg's orcas are separate species; for now they are generally treated as subspecies. The name "killer whale" likely comes from Basque sailors who called it a "whale killer."
- Varieties and forms
- Besides Residents and Bigg's, the North Pacific has an "offshore" type, and several distinct types live around Antarctica.
Conservation
- IUCN Red List
- DDData DeficientNot enough data yet to assess
- Status
- The Southern Resident population is listed as Endangered under the Endangered Species Act; it numbered 74 whales in the July 2025 census. All killer whales in US waters are protected under the Marine Mammal Protection Act.
- Threats
- Shortage of prey (especially Chinook salmon), chemical pollutants that build up in their bodies, oil spills, entanglement in fishing gear, and vessel noise and disturbance.
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