One could be forgiven for thinking that the orca is a whale. First of all, it’s commonly known as the killer whale. Then, you’ve got its size to consider: at up to 30 feet long, the orca is a whole lot bigger than any dolphins that come to mind. Plus, it doesn’t have the distinct bottlenose that dolphins sport.
If it looks like a duck, swims like a duck, and quacks like a duck, it’s probably a duck. In this case, all signs point to whale. But no, the orca is not a duck…I mean, whale. So, are orcas whales? The orca is actually, despite all evidence to the contrary, a dolphin.
A Whale of a Dolphin
Once again, it's completely understandable that someone would reason that an orca is a whale. After all, they are a member of the infraorder Cetacea, which contains all whales and dolphins and comes from the Latin word cetus, for whale. Score one for whale.
To go even further down the rabbit hole, orcas are a part of Odontoceti, or the toothed whales. That’s a lot of “whales” piling up in the killer whale’s taxonomic tree.
But alas, this is where the whales stop. Within the Odontoceti, orcas are members of Delphinidae or the dolphin family. While other toothed whales, like the sperm whale or narwhal, are considered whales, all members of Delphinidae, including orcas, are not. They’re dolphins.
Misnomer
It turns out, while we’ve been calling them killer whales for so many years, we’ve actually had it backward. The name started out as “whale killer,” because sailors witnessed them attacking and eating the calves of large whales. Whoops.
But don’t worry, killer whales aren’t the only misnamed dolphins. The melon-headed whale, pygmy killer whale, false killer whale, and pilot whales are all, likewise, dolphins. They each got their “whalehood” due to their size, but that doesn’t make it so. You can’t tell people you own a wolf just because your dog is really big.
A Better Name
The term “orca” has recently come into favor, largely because of killer whale’s negative connotations, but there’s a second reason the name is superior: it’s accurate. So, for me, since I don’t feel like calling them “killer dolphins,” maybe I’ll stick to orca.