Can animals commit suicide?
It’s hard to discern the intent of animals who can’t describe their intent to us (or, in the instance of many parrots and a few trained apes, can, but poorly). But I know of one type of occurrence which is, nearly inarguably, intentional suicide. It’s called Quaker Mutilation Syndrome, where a Quaker parrot goes beyond the common problem of feather plucking to mutilation of its own flesh. Birds affected by QMS will tear into their own flesh until they hit a major blood vessel and bleed out. QMS has many causes, many of which are physical in nature (of course many human suicides are caused by physical suffering). But QMS is also associated with psychological causes, and in such a context it looks very much like suicide caused by mental illness. QMS in fact has been treated with the human depression drug Prozac. I would not be surprised to learn that other animals, and especially other highly intelligent animals (apes, cetaceans, parrots, crows) engage in behaviors which appears similar
Most of them are probably accidents but some animals willingly bite the big one, usually as a mating thing. There’s a certain spider that allows himself to be eaten by the female after mating and certain preying mantises can’t mate until their head is taken off. Whether or not they know of their own impending doom is debatable but all creatures have a survival instinct that precludes suicide. Humans, with their complex brain and all of the things that can go wrong with it, like clinical depression and dementia, seem to be the only creatures that will plan and carry out their own end.
