Head to head
Orca vs Bottlenose Dolphin
The killer whale, or orca, is a dolphin, the largest member of the dolphin family, Delphinidae. It shares the family's sleek body, echolocation, tight social groups, and high intelligence with the bottlenose dolphin, the animal most people picture when they hear the word dolphin. The difference is one of scale and specialisation.
| Orca | Bottlenose Dolphin | |
|---|---|---|
| Family | Delphinidae, the dolphin family | Delphinidae |
| Length | 6–8 m (males larger) | 2–4 m |
| Weight | Up to about 6 tonnes | 150–650 kg |
| Diet | Fish, seals, sea lions, dolphins, sharks, whales; varies by population | Fish, squid, crustaceans |
| Social structure | Stable matrilineal pods for life; distinct dialects and cultures | Fluid groups of a few to a few dozen; some long-term bonds |
| Predators | None | Large sharks, and occasionally orcas |
| Range | All oceans, pole to pole | Temperate and tropical seas worldwide |
| Lifespan | Females often 50–80+ years | 40–60 years |
Orca vs Dolphin: common questions
Is a killer whale actually a whale or a dolphin?
Both, in a sense. All dolphins are toothed whales, part of the larger group Cetacea, and the orca is a dolphin, specifically the biggest species in the dolphin family. So calling it a killer whale is not wrong, because it is a whale in the broad sense, but zoologically it sits squarely within the dolphins, alongside the bottlenose, the spinner, and the common dolphin. The name killer whale is thought to come from "whale killer," a description sailors gave it for its habit of hunting large whales.
How much bigger is an orca than a bottlenose dolphin?
A great deal. A large male orca can be 8 metres long and weigh 6 tonnes, while a big bottlenose dolphin is around 3.5 to 4 metres and 500 kilograms. An orca is therefore roughly ten times the weight of a bottlenose and about twice the length, and its dorsal fin alone, in an adult male, can stand as tall as a person. Despite the size gap, the two are close relatives with a very similar body plan.
Do orcas eat dolphins?
Some do. Orca populations specialise: some eat only fish, some only marine mammals, and some target specific prey such as seals or sharks. Mammal-hunting orcas will take dolphins, including bottlenose dolphins, and dolphins in areas frequented by these orcas show clear avoidance behaviour. Fish-eating orcas, by contrast, ignore dolphins entirely. So whether an orca is a threat to a dolphin depends entirely on which kind of orca it is.