Are Killer Whales Whales or Dolphins?
Killer whales, otherwise known as orca, are commonly referred to as whales. They’re large, like whales. Powerful, like whales. And range across all oceans, like whales. But they’re not whales.
Killer whales aren’t whales, killer whales are actually dolphins.
Sounds crazy, doesn’t it? Except when you consider the other name for a killer whale: Blackfish. We’re sure we don’t need to argue the case that a killer whale is not a fish.
Is a Killer Whale a Dolphin?
A killer whale is a dolphin. They belong to the animal family of Delphinidae, which includes more commonly known dolphins like bottlenose. Killer whales are also Cetacea, which covers all baleen whales, dolphins, and other large aquatic mammals of similar genealogy.
For argument's sake, we’ll mention that a killer whale can technically be called a whale, as all dolphins are actually considered under the order of toothed whale, but this order also includes porpoise, sperm whales, beluga, narwhal, etc. You wouldn’t call a bottlenose dolphin a whale, because it is part of the very specific dolphin family. This is much the same way you wouldn’t call a human a simian, despite the fact we are part of the animal order.
Killer whales aren’t just closer relatives to the bottlenose dolphin than a whale like a humpback whale, they are part of the same family, which means they're a dolphin in exactly the same way a bottlenose is.
Why Are Killer Whales Dolphins and Not Whales?
When you really think about it, there are actually a fair few obvious reasons as to why a killer whale should be classified as a dolphin and not a whale:
Physiology - Killer whales are long and sleek with rounded heads and tall dorsal fins, much like dolphins. They may be far larger than most dolphin species, but at a maximum of 9 metres in length (usually between 5 and 7), they’re far smaller than most whales, with humpbacks as an example growing more than twice their size.
Echolocation - Baleen whales cannot use echolocation. This trait is specific to toothed whales including dolphin, beluga and sperm whale. While whales are famous for their song, this is not a form of sound imagery but instead for communication.
Behaviour - Killer whales hunt mammals and large fish. They are always found in large and closely-knit family groups. They also stay close to the shore to feed and aren’t diving predators. These are not characteristic behaviours of whales but are of dolphins. Except for hunting mammals, while killer whales aren’t the only dolphin to do this (false killer whales, for example) it is a rarer behaviour.
Really, the biggest argument for a killer whale being a whale and not a dolphin is its name. This is why many people prefer to call them orca.
Why Are Killer Whales Called Killer Whales If They’re Dolphin?
The reason is actually quite simple. They’re called killer whales because that’s what they are. Killers of whales.
Ancient sailors used to observe orca killing large whales out in the ocean, and referred to them as asesina ballenas, which is Spanish for whale killers. When translated to English, the name got changed as killer whale simply sounded better.
Over time, the name really has gotten lost in translation, with many people taking it very literally. Of course, it makes sense to do so. Humpback whale, blue whale, fin whale. All whales have whales after their name. Then look at dolphins. Bottlenose dolphin, common dolphin, Risso’s dolphin. It would make sense for a killer whale to actually be called a killer dolphin, if we were to apply normal naming conventions.
But when has the English language made sense?
At the end of the day, killer whales don’t really care what you call them. They do care about how you observe them though. When looking for the best places to see killer whales, always make sure you opt for wild and ethical excursions and avoid marine parks. Whale or dolphin, both only belong in one place: the open ocean.
Learn more about orca with our killer whales fact guide.
