Death, seen as the idea of “ending it all,” is an abstraction. To know that you will die one day is to engage in abstract thought. Animals don’t do that. If they did, we’d be in big trouble.
Yes! Now there is a Darwinian explanation of suicide
It’s amazing what passes for insight among evolutionary psychologists. How would it help anyone decide how to help a depressed person? Read the whole thing for sure. It gets into beehives and such.