I was leading a conversation group recently and one of the guys said that orcas are dolphins. No, no, I assured him, orcas and dolphins are certainly related, but they are separate species. Nope, he insisted, orcas really are dolphins. Seriously, I countered, gorillas and human beings are both members of the primate family, but that doesn’t make a gorilla a human being, and it doesn’t make an orca a dolphin.
He remained adamant, as did I, and the group meets again this week, and I’d like to either start it off by being smug or never raise the subject again, depending on how right I turn out to have been.
I realize that this should be easily solvable with my friend Google, but the sources I’ve read that stated a clear ‘Yes’ to the question were questionable at best, and the sources whose answers I would have trusted didn’t say, ‘Yes, orcas are dolphins. This is the answer. You’re done now. Go away and stop bothering me.’ For that matter, neither did they say, ‘No, orcas aren’t dolphins. Are you always this stupid or was I just lucky enough to catch you on a bad day? Pffft.’
So I turn to the source I trust above all others, the smartest collection of people anywhere, you clever clogs yourselves, and I ask you to give me a lovely, straight answer: Are orcas dolphins?
There’s no such species as “dolphin”. “Dolphin” describes a whole bunch of related species and genera. So Orcas are dolphins, same as bottlenose dolphins, and Amazon River dolphins and so on.
Keep in mind that what we commonly call whales and dolphins aren’t scientific categories. They are all cetaceans and some “whales” (like Orcas) are more closely related to what we commonly call dolphins (Flipper) than they are to something like a grey whale.
Ask the guy if he knows the difference between an eagle and a hawk.
I used to volunteer for a Dolphin hospital.
Marine mammals (Cetaceans) are either whales, dolphins, or porpoises.
Though orcas and other dolphins are all seperate species, they are part of the same Family, Delphinidae. All Cetaceans in the Delphinidae Family are dolphins.
This link shows other species of dolphin as well. http://www.everythingdolphins.com/SpeciesPG.htm There are probably a lot more than you thought.
Orcas are dolphins if you say that dolphins are delphinid cetaceans. However, that leaves out the “river dolphins”, which are different clades within Odontoceti. Going back a level, though, to Delphinoidea, allows you to include all oceanic dolphins and river dolphins together. So, you can say instead that all dolphins (and killer whales) are delphinoid cetaceans.
Cetaceans are whales, dolphins, or porpoises, but not all marine mammals are cetaceans. There are also the pinnipeds (seals, walri, and such) and sirenia (manatees, sea cows, etc.). Plus debateably some members of Carnivora like otters and polar bears.
As I am sure is apparent by now, the answer isn’t straightforward. It depends on what you mean by “dolphin.” Orcas are a member of the family Delphinidae, commonly referred to as the dolphin family, although it includes several other species that are called whales besides orcas, such as pilot whales. The common Bottlenose Dolphin also belongs to this family. So orcas belong to the dolphin family, but are a different species from the dolphins most commonly found in captivity.
The claim “Orcas are dolphins” is similar to the claim “Lions are cats”. “Cat” can mean specifically the domestic housecat, or it can mean any number of cat species including lions, tigers, jaguars, bobcats, and on and on. Sometimes when people say “dolphin” they’re talking only about the bottlenose dolphin. But the bottlenose dolphin *Tursiops truncatus *isn’t the only species of dolphin, and it wasn’t always the generic dolphin, that would be the common dolphin Delphinis delphis.
Sorry about the ego, but you weren’t right. It would be wrong to go away from this thinking your friend was in any way wrong.
You had your analogy right in the OP, you just didn’t realize how it applied to the subject matter. You said humans are primates, and apes are primates, but that doesn’t make humans apes.
Similarly, “dolphins” are the equivelant of primates here. They’re a family that includes many species of dolphins, which includes Orcas.
You’re doing the equivelant of saying “apes can’t really be primates because humans are primates and apes aren’t human”
As I noted above, “whale” is not a scientifically meaningful term, so your teacher was uninformed. They are both cetaceans. “Whale” is a term in the vernacular that divides some cetaceans into groups based on visual observation, but that ignores the cladistic relationship between the various species.
Your pride may take a hit, but you’ll gain respect by admitting you were wrong – which I think would increase your pride. I hate being wrong, but I’ve posted ‘I stand corrected’ more than once here. Data can be disputed when there is conflicting data. For example, X is true and conflicting Y is true. An argument ensues over the interpretation of the data. But if all members of the Delphinidae Family are dolphins, and orcas are members of the Delphinidae Family, then orcas are dolphins.
I’d say the best strategy would be to bring it up yourself. Admit your mistake. Explain why you came to your conclusion, but don’t try to weasel out of it. ‘OK, guys, remember the orca discussion? I was wrong. By analogy I said humans and gorillas are not the same. Killer whales and oceanic dolphins are both members of the Family Delphinidae, just as humans and gorillas are members of the Order Primates. I just wasn’t thinking of the scientific classification. I stand corrected.’
You will have shown that A) You actually sought out the correct answer instead of obstinately sticking to ‘what you know’; and B) You are a confident enough person to admit your mistake when presented with new information.
