Female spotted hyenas are bigger and more aggressive than the male of the species, and their dominance makes the males unusually submissive. The reason for this is that the female produces male sex hormones, which have the additional effect of making the female genitalia looking very similar to that of the male. Indeed it was falsely believed for a long time that hyenas were hermaphrodites and could change their sex. The pseudopenis, which is erectile, is in fact an elongated clitoris and the pseudoscrotum consists of fatty tissue. Copulation is a complicated business with the vagina being entered and exited through the pseudopenis. When a mother gives birth for the first time, the clitoris tears to let the cub out. This is not just agonizing, it’s often lethal.

Text adapted in part from Dr Tatiana’s Sex Advice to All Creation