Killer Whale's Dorsal Fin

After watching the news the past day about the Killer Whale that got a little rough with its trainer I was reminded of something I’ve always wondered about. Why does the dorsal fin of Killer Whales always flop over in captivitybut remains erect in the wild. All the nature shows comment on it but none explain why.

As far as I know they aren’t sure. It doesn’t just happen in captivity, though - they’ve found orcas in the wild that have droopy dorsal fins. I’d google “orca dorsal fin”, but you’re not going to find much more than theories.

I’m terrified of orcas. They freak me out hardcore. But you know what they say, know thy enemy. I’ve learned a lot about them. Fascinating, if creepy.


Nobody knows for sure, but there are a few theories:

  • Orcas in captivity might swim in circles that put uneven pressure on the fin and cause it to droop over.

  • Orcas might need to pressure of deep dives to help stiffen the connective tissue that supports the fin; since whales in captivity spend all of their time near the surface, they don’t get the opportunity to dive. This hypothesis is apparently supported by watching whales in the wild – evidently those who spend their time on the surface tend to have droopier fins.

  • The difference in diet might result in weakening of the tissues.

  • Aliens.

In wild orcas and related cetaceans have been observed with disfigured dorsal fins, either as a cause of the orcas damaging the base of the fin or as assumed as a cause of poor health related to pollution. Some info on this here .

I would assume that the orcas living in confined quarters as a seaworld pool would have lots of opportunities to bang up their large dorsal fin against the bottom and walls. No wonder the fins are drooping.


I’ve always heard that droopy dorsal fins were a sign of depression in the captive animal. :dubious:

That opens the “can animals HAVE depression?” debate. I highly doubt, however, that a mental illness like depression would have a physical manifestation like a drooping fin, unless it were some sort of weird orca-self-mutilation (which is possible, I suppose). Most of the physical things you notice about depression in humans is self-caused; gain or loss of weight due to the depression, cutting, poor hygene, etc.

I don’t know how captive orcas feel about it, but if I were them I’d LOVE being in captivity. Never having to hunt again? Doing some flips in exchange for fish? Hell yeah.


Fight my ignorance. I am guessing that your location of NV means Nevada in the USA? Do you get a lot of Orca’s there? How did you come to be so afraid of them that you have to reasearch them?

The dorsal fin is a soft cartilage-type of material. The orca dorsal fin is relatively tall compared to other marine animals. Given the size of a killer whale in the first place, that gets to be quite a bit of weight standing straight upwards.

Though killer whales swim in all of the world’s oceans, they are mainly found in the colder waters of the polar regions. It’s my understanding that colder temperatures make the cartilage material harder, encouraging straight growth. Warmer temperatures allow the material to be more pliable and permit it to bend once it reaches a particular height. I am assuming that this is a hereditary trait and not something that changes if the orca swims from a polar region to a tropical region, though I could be wrong about that.

I can say with absolute confidence that it’s not because the animal is “sad.” That notion is strictly from the realm of cartoon-land.

Why do there need to be orcas nearby for her to research them? She’s afraid of them, it’s not uncommon as they are a very large animal and are known to be vicious in the wild. It doesn’t mean she fears Orca attacks every time she goes outside, it just means they give her the willies. I have the same problem with leeches, which aren’t very prevalent in the arid suburbs of Adelaide, South Australia.

And sometimes people research what scares them in order to try and combat that fear. As Tasha said, know thine enemy.

Spending your entire life in the equivalent of a 20x20 room or smaller? Rarely or never being able to interact with members of your own species (and this in a species that forms stable “families” that last for decades, with different families organized into “tribes”)? Sounds fun to me!

There are certainly instances of captivity that fit your description. But there are those — such as the San Diego Wild Animal Park — that don’t. I agree with your point, but it’s wrong to liken all instances of captivity as prison-cell experiences.

My aunt had two dogs, raised together from puppyhood. One of them died in middle age from cancer and the other “grieved herself to death.” I don’t know any other way to put it. She was disspirited, she wouldn’t eat unless hand-fed and then only a tiny bit, she wouldn’t play. All she wanted to do was lay in their shared doggy bed. The vets could find nothing physically wrong with her. She died less than six months after the other dog.

An orca, by all accounts, is more intelligent than a dog. If a dog is capable of grief/depression (which I believe they are, based on the prior example and others I have seen) an orca would certainly be capable of it.

I can’t imagine I’d like to live in a prison cell, even if everyone around me was kind. I’d miss my family. I’d miss walking in the woods. I’d miss being able to select my own food. I’d hate the monotony and being stuck with a cell mate or two that, while they were nice and all, I didn’t really* like.* I’d long to meet other people, to pick my own mate and to be able to run as far as I liked.