Much attention has recently been devoted to 'gay' animals. It's not the fact that many species have enthusiastic homosexual lives that should be surprising – there are convincing theories about how gay sex is evolutionarily adaptive. The short version of the argument: Social activities like grooming offer no immediate reproductive benefit, but they do help to create beneficial social arrangements. In shame-free animal societies, sex is just another bonding activity.
To the next nature enthusiast, what is interesting is how human culture has decided what is appropriate in animal culture. For years, zoos would not display Bonobos because their sexual behavior was deemed too inappropriate for delicate audiences. Field researches routinely assumed all species were heterosexual, and any encounters that fell outside of the straight-and-narrow were 'mistakes' or 'practice.' Only in recent years, it seems, has human culture advanced enough to catch up with real nature.