Sex among members of species other than ours is one of the topics that primatologist Franz de Waal addresses on Freakonomics. The informative article has comments on a number of subjects, including animal rhythm, animals who won’t cooperate when rewards are unequal and, most of all, bonobo sex, which is plentiful, clearly “bi” and serves a lot of different purposes.
In addition, thanks to the Neuroethics and Law blog, we have the link to de Waal’s site about elephant self-recognition. Not many species recognize themselves in mirrors. Cats, for example, don’t. That elephants do may reveal something about the evolution of social animals.
All this is worth reading, and is full of the sorts of useful details for philosophy classes. It’s also handy for throwing cold water on convictions about what is natural.