Animal Sex: News and Features

Scientists have figured out why some species have more females than males and others have more males than females. Turns out, sex chromosomes are the culprits.

Sea hare sex involves hermaphrodites, mating chains and lengthy mating events.

A female water snake in Missouri can do something that no human woman can (no matter how badly she might want to).

A Twitter hashtag, #JunkOff, illustrates the steamier side of biology — and its importance to understanding evolution.

The complicated world of hyena sex involves social hierarchies, weird and potentially dangerous courtship rituals and female pseudopenises that make forced sex impossible.

When it comes to sex, are butterflies as nurturing and gentle as they appear to be, or is there a more aggressive side to their mating?

Black widow males destroy large sections of their mates' webs in order to ward off potential rivals.

Check out these images of the northern giant mouse lemur, Mirza zaza, which has the largest testis relative to body size of any primate.

Antechinus sex involves ambushes, intermittent copulation lasting 14 hours and ultimately suicide.