Extra chromosomes allow all-female lizards to reproduce without males

Whiptail lizards are a fairly ordinary-looking bunch, but some species are among the strangest animals around. You might not be able to work out why at first glance, but looking at their genes soon reveals their secret – they’re all female, every single one. A third of whiptails have done away with males completely, a trick that only a small minority of animals have accomplished without going extinct.