Do animals commit suicide?

Matt:

Are humans the only living creature that commits suicide?

-- Morbid Mark, the net

Intent. Can animals form intent in their feral little brains? Sit down and say, hey, man, this grubbing for food and mates doesn't cut it? There's gotta be something better? Intent would seem to be the key, though people do argue. Some say male spiders eaten by their mates after copulation are committing suicide. My guess is there's no female spider so hot that a male would knowingly make the sacrifice. The urge to mate isn't connected in his brain with death. And that old story about the lemmings running in herds off a cliff when populations boom? That's a crock, of course. A Disney movie perpetuated the myth by staging a lemming suicide leap, but that was just Hollywood, not science. As you might expect, dolphin lovers swear the animals suffer soul-rending angst and have been known to kill themselves by repeatedly ramming their enclosures. Dogs or chimps might pine away for a dead master or mate. But science in general figures it's a stretch to believe that any resulting death would be intentional, or that an animal can even conceive of the idea of their own death. Animals' instincts are to eat, avoid danger (death), and reproduce, not to hop out of the gene pool prematurely.