As part of his ongoing "Fantastically Wrong" series at Wired.com, Matt Simon investigates the ancient legend that
beavers will chew off their own testicles when pursued and throw them back at their pursuer, in this way making their escape. The legend was mentioned in Aesop's Fables and popped up in various works of natural history, until it was debunked in the 17th century by Sir Thomas Browne who pointed out that the testes of beavers don't hang outside their body. They're internal. So it would be difficult to chew them off, even if the beaver wanted to.
Comments
Certainly fantastically wrong, but no so wrong as that vultures had virgin births, or that bears vomited their young as shapeless lumps of flesh and licked them into bear cub shape.