Consider the hare and the hyena. The hare, Clement of Alexandria told readers of his 2nd-century sexual self-help manual Paedagogus, was thought to possess both male and female sexes and swapped their roles from year to year. As for the hyena, it was believed to acquire an extra anus annually and ‘to make the worst use of these added orifices’, as Michel Foucault puts it in the newly translated fourth volume of his History of Sexuality.