Is there any documented evidence for suicide among vertebrates other than humans? Lemmings not accepted !
Well, there are certain behaviors that may qualify. The clearest example I know of would be sexual cannibalism, and more specifically (source):
That sounds pretty suicidal to me...
A less fragrant but commoner example is that of mothers dying to nourish their offspring. Again often seen in spiders, the best example I know of is the giant pacific octopus (Enteroctopus dofleini). The female will chose a den and lay her eggs. She will then spend her last weeks tending her young, never leaving the lair to hunt. Eventually she dies of hunger and her body nourishes her young. My source here is the wonderful BBC life documentaries.
Neither of these are vertebrates of course but still, I thought the suicidal little spider was interesting.