For Emei moustache toads, a top-quality moustache is an essential, and violent, weapon … During the breeding season, each male grows 10 to 16 spines. "They are as sharp as a pencil lead" says Cameron Hudson of the University of Guelph in Ontario, Canada, adding that the frogs "do try to stab you a bit when you pick them up".

The males fought underwater, head-butting each other in the belly to drive their spines into the other toad's flesh. "I've never seen any of them kill each other," says Hudson. "But they get a lot of puncture wounds."