Orca vs Killer Whale
Verdict: There is no difference. Orca and killer whale are two names for one species, Orcinus orca, which is really the largest dolphin. Agencies use both, so pick the one your audience expects.
Orca and killer whale are different names for the same animal, Orcinus orca. It belongs to the dolphin family, Delphinidae, and is the largest member. NOAA Fisheries and the Alaska Department of Fish and Game title their pages killer whale, while the U.S. Fish and Wildlife Service lists it as orca with killer whale in parentheses.
So this page cannot sort animals into two kinds. The real differences are among populations, called ecotypes. In the North Pacific, resident killer whales eat fish and transients eat marine mammals. The quiz here helps you choose which name fits a situation, not which animal you are seeing.
Orca vs Killer Whale side by side
| Trait | Orca | Killer Whale |
|---|---|---|
| Species | Orcinus orca | Orcinus orca |
| Family | Delphinidae, the dolphin family | Delphinidae, the dolphin family |
| Where the name appears | U.S. Fish and Wildlife Service species page | NOAA Fisheries and Alaska Fish and Game species pages |
| Appearance | Black back, white chest and sides, white patch above and behind the eye | Black back, white chest and sides, white patch above and behind the eye |
| Size (males) | Up to about 31 ft and over 6 tonnes (FWS) | Up to 32 ft; North Pacific males about 27 ft (NOAA, ADF&G) |
| Size (females) | Up to about 28 ft and about 5 tonnes | Females average about 23 ft in the North Pacific |
| Diet | Varies by ecotype: fish for some, marine mammals for others | Fish-eating residents and mammal-eating transients in the North Pacific |
| Lifespan (NOAA) | Males about 30 to 60 yr; females about 50 to 90+ yr | Males about 30 to 60 yr; females about 50 to 90+ yr |
| Speed | Often over 35 mph | Often over 35 mph |
Last verified October 2026. Typical values; individual animals, products and local prices vary.
Which one fits you
Orca
- You want a short, familiar name that mirrors the scientific name Orcinus orca.
- You are writing for the general public and want to avoid implying it is a whale rather than a dolphin.
- You are matching the U.S. Fish and Wildlife Service page title, which lists orca first.
- You want a compact, headline-friendly name that fits on a sign or label.
Killer Whale
- You are quoting NOAA Fisheries, which titles its species page killer whale.
- You are writing about Alaska waters, where Fish and Game uses killer whale.
- You are searching older reference material and agency pages that use the longer name.
- Your audience knows the name from everyday speech, even though it is a dolphin.
How this works
This page covers a naming question, not an identification one. The quiz asks which agency wording, length, region and framing you need, then suggests the name that fits better. It checks agency wording, name length, region and framing, and each answer leans one way.
Because both names are correct, the result is a style suggestion. Regional ecotypes, such as resident and transient, are the real differences in diet and behavior and are not a naming matter. Either name is accepted in everyday writing. If you cite NOAA, use killer whale, and if you cite the Fish and Wildlife Service, orca is fine.
Where these numbers come from
The figures and defaults on this page are based on:
- NOAA Fisheries: Killer Whale, Family, size, lifespan, diet and ecotypes of the killer whale (checked October 2026)
- Alaska Department of Fish and Game: Killer Whale Species Profile, Scientific name, dolphin classification, size and resident versus transient diet (checked October 2026)
- U.S. Fish and Wildlife Service: Orca, Orca name, size, markings and speed (checked October 2026)
Naming guide. Orca and killer whale are the same species, and wild marine mammals should be watched from a legal distance.
Frequently asked questions
Are orcas and killer whales the same animal?
Yes. Both names refer to Orcinus orca. The animal is the largest member of the dolphin family, Delphinidae.
Is an orca a whale or a dolphin?
A dolphin. It is the largest member of the dolphin family, though it is commonly called a whale.
Do all killer whales eat the same thing?
No. In the North Pacific, resident killer whales eat fish such as salmon, while transients hunt seals, porpoises and other marine mammals. Diet depends on learned hunting behavior in each ecotype.
How big do orcas get?
Males can reach about 27 to 32 feet and several tonnes, and females are smaller, around 23 to 28 feet. NOAA lists males as living about 30 years and up to 60, and females around 50 and up to 90 or more.
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