Killer Whales are a type of Dolphin

Over in this thread about Heinlein, a weird discussion broke out about dolphins.

Granted, it’s a random hodgepodge of a thread wandering around the topic rather wildly. Nevertheless, the dolphin discussion seems just a bit far afield even for that. So I decided to start a new thread.

Apologies for the cumbersomeness, but I’m dragging over previous comments to get the conversation in one place. Multiquote for some reason didn’t carry over, so manually quoted.



Next post is my reply to the above.

First link is snafu. Try Porpoise.

So much misconception.

  1. Orcas are dolphins - they are in the Delphinidae family. That is the family with all the dolphin genuses.

  2. All dolphins are carnivores. They are avid hunters. (Fact is, most sea life are hunters, barring molluscs and microscopic animals (rotifers).)

  3. Reviewing wikipedia on killer whale attacks on humans, there are only seven cases listed of wild orcas attacking humans. Only one of those attacks was fatal - in 1894 a midshipman was taken from an ice floe by an orca. Possibly mistaken for a seal. Several of the attacks appear to be mistaken identity, and aborted as soon as the orca realized the prey was not a seal. Included in this is the one surfer bitten in 1972, and a 12 year old boy who was bumped but not bitten in 2005. Also, a group of orcas tried to tip an ice floe with an explorer and his sled dog team. Possibly confusing the dogs for seals. One case the pod of orcas sank a wooden boat, but did not kill any of the people. Another case a pod of orcas attempted a “wave wash” on an inflatable zodiac boat of a crew filming them. They had been doing the wave wash on ice floes to hunt seals. A final case was a fisherman who had a bag of crayfish and urchins tied to his arm. The orca took the bag and dragged the man along with it until the rope came free from his arm. Apparently the orca wanted the stuff in the bag, not the man - he was just a victim of being tied to dinner.

Attacks on humans by captive killer whales is longer, but more confusing. There does not appear to be any predation - no humans getting eaten, but some killed by being drug under water and bitten. Some could be roughhousing getting out of hand, many appear to be cases of moody killer whales acting out, or hormonal teenagers.

All in all, I would say that orcas are generally fairly friendly towards humans, and the incidents otherwise all appear to be unintentional or provoked.

  1. “Wolves of the sea” is rather silly - why not “lions of the sea” or “weasels of the sea”? A better case could be “bats of the sea” - they are predators who use echolocation to swoop in on unsuspecting prey.

  2. Personally, I would be leery of them if I ran across them in the wild, simply because of their size and the fact that they are wild animals. But I would feel much safer swimming and having an orca show up than, say, hiking in Alaska and a pack of wolves showing up, or camping in bear country and seeing a bear or two check out my campsite.

I don’t know who your marine biologists are, but they don’t appear to be very good ones.

Dolphins are of the family Delphinidae. There are numerous genuses of dolphin, including Delphinus, Lissodelphis, Sousa, Tursiops, and several others. Also included in that family are Orcinus (killer whales), Peponosephala (melon-headed whale), Feresa (false killer whale), Globicephala (pilot whales), and Lissodelphis (right whales). All of these are considered genuses of oceanic dolphin.

Porpoises share the superfamily of Delphinoidea, family of Phocoenidae. All the dolphins are Delphinoidea, family Delphinidae.

The fish with the name “dolphin” is the order Coriphaenidae, species Coriphaena. They are called “dolphinfish” to distinguish them from the mammals, and the are now more often called “mahi mahi” to avoid confusion.

Pampano are of a different order, Carangidae. They are not dolphinfish.

IANA Marine Biologist, but I play one on the internet.*


  • Homage to a classic TV commercial.

I’ll have a much easier time accepting that orcas are leery of humans than accepting that they’re friendly toward humans. Why on earth would they treat humans as anything other than calorie sources or dangers?

IAAMB (or I wuz one).

Some few fish are plant eaters and a lot of animals, even the largest animals- are filter-feeders, which I wouldn’t call being a “hunter”.

Otherwise good post.

On a similar nitpick, my daughter is completely shark-obsessed, so we read lots of books about sharks. Over and over they refer to the whale shark as the largest predator on earth. And I’m like, what about the blue whale? Just because it eats teeny weeny krill doesn’t mean it’s not devouring the flesh of the living in order to fill its belly.

Seems like a slam-dunk, then. That’s the way the terms are defined. How do you dispute it?

Nineteen is a prime number.
The Ford Focus is an automobile.
Hamlet is a play, and is also sometimes a book.

Of course, it is rather amusing to read Moby Dick, especially the lengthy sequences where Melville valiantly struggles to prove that whales are “fish.” Sometimes, not everyone gets the memo.

(My b.i.l. is an amateur botanist, and is amused by revisions that come along in taxonomies, where a plant used to be in one family, got moved to another, then got moved back again. So, of course, it’s conceivable, although highly unlikely, that some group will decide to move the Orcas out of the Delphinidae.)

(And Pluto is still a planet, dadgum it!)

Especially because whale sharks are also filter feeders that sustain themselves mainly on plankton and krill.

Well, Plankton can also be Protista , Algae and Archaea. So, I would not usually call a filter feeder a predator. Altho, since filter feeders do kill the plankton, under some definitions they would be included.

The whale shark is by no means the largest predator on Earth, that’s the Sperm Whale. Even if you called a filter feeder a predator, several whales are bigger as you said.If filter feeders are predators, of course it would be the Blue Whale as you said.

For a certain value of “fish” the whale shark is the largest “fish”. (“Fish*” no longer has much of a useful scientific meaning- since many use it to contain both the Chondrichthyes and the* Osteichthyes* which are not very closely related)

  • wiki:A fish is any member of a paraphyletic group of organisms that consist of all gill-bearing aquatic craniate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups. …
    Because the term “fish” is defined negatively, and excludes the tetrapods (i.e., the amphibians, reptiles, birds and mammals) which descend from within the same ancestry, it is paraphyletic, and is not considered a proper grouping in systematic biology. The traditional term pisces (also ichthyes) is considered a typological, but not a phylogenetic classification.

No. These are Right Whales. Lissodelphis species are Right Whale Dolphins. Just to be pedantic.

I don’t know about “wolves of the sea”, but I know that orcas are “apex predators”, meaning they’re at the top of the food chain. They have no natural predators themselves. They’ll even eat great whites.

So you could say they’re the “badasses of the sea.”

Yes, Orcas are dolphins, in that they are in the family Delphinoidea. Some people would also describe them as whales: the term is used either to describe all of Cetacea (in which case they are), or Cetacea except for dolphins and porpoises, in which case they’re obviously not whales.

I was never a fan of the whale-dolphin-porpoise classification anyways. A bottlenose dolphin is much more similar to a sperm whale than the sperm whale is to a blue whale.

It’s just as fun as the whole turtle/tortoise/terrapin thing. Does the term “turtle” describe all of Chelonii, or does it exclude the terrestrial species? And what the hell is a terrapin? You’ll get people arguing vehemently over what at the end of the day comes down to semantics.

In one sentence please: What is the debate?

I’m not entirely sure, but I think it might be “Are non-cladistic taxonomical terms useful?”

Because other dolphins tend to be friendly toward humans? I suppose leery is an option, I don’t have a comprehensive guide to orca/human interaction in front of me.

Okay, perhaps “hunter” is a bit of a stretch for filter feeders. I was trying to figure out where filter feeders fit in, anyway. They eat krill, which are animals, but do they also eat the plankton, too, or is that just the feedstock for the krill? Enquiring* minds want to know.

MIchelleRose was arguing that orcas are not dolphins, and dolphins are actually porpoises, and marine biologists don’t like calling bottlenose dolphins “dolphins”.

Ah, thanks for the correction.

**MIchelleRose **was claiming that orcas are not dolphins, and that dolphins are actually porpoises, and that marine biologists don’t like calling bottlenose dolphins “dolphins”.

If nobody feels this is actual debate material, move the thread to IMHO or MPSIMS or the Pit or whatever - I don’t give a fuck. Just don’t put it in Marketplace - I never go there.


  • Spelled like the magazine from the slogan.

Perhaps the large marine mammals that feed on plankton and krill might be thought of as “grazers” as opposed to those who hunt and prey on larger sea life?

Some filter feeders sorta “hunt” krill, but others simply strain plankton. Some filter feeders have a filter which would normally allow the microscopic sized plankton to go thru, saving the “larger’ krill as their meal. (there are actually a few species of krill that get almost 6” in length, so Krill arent always so very tiny. Most are about 1cm or 1/2 inch, however. ) Krill do swarm, so a krill feeder can be sure of getting a lot of krill per “mouthful”.

Until this thread, I might have agreed. There is such a thing as “folk taxonomy,” and it tends to vary from academic taxonomy.

There are people who think Pandas are “Bears.” Shrug. Folk taxonomy is a little like intuitive physics: it’s wrong, but worth studying, to understand why it is so compelling. (Who among us has not thought that the path of an object thrown from a spinning carousel is curved? It feels like it.)

Pandas are bears. Were you thinking of Koalas (or red pandas)?

I once met Richard Ellis, who wrote the book Great White Shark. During a lecture he was giving, a student asked a question about orca predation on great whales. Ellis asked the class “What does an orca eat?” and then answered himself: “Anything it wants.”

Well, there ya go. I’d been told, in a thread much like this one (entirely different BBS) that they weren’t!

I not only have fallen for folk taxonomy, but for folk debunking!

(I just did a quick search, and found the adviso, “Scientists no longer believe that giant pandas are more like raccoons than bears.” I hadn’t been paying attention, and missed that memo!)