© BBC Earth newsSpanish ribbed newt
One amphibian has evolved a bizarre and gruesome defence mechanism to protect itself against predators.
When attacked, the Spanish ribbed newt pushes out its ribs until they pierce through its body, exposing a row of bones that act like poisonous barbs.
The newt has to force its bones through its skin every time it is attacked, say scientists, who have described the form and function of the barbs in detail.
Yet this bizarre behaviour appears not to cause the newt any ill effects.
The ability of the Spanish ribbed newt to expose its rib bones was first noticed by a natural historian in 1879.
But scientists have now used modern photographic and X-ray imaging techniques to reveal just how the animal does it. The ribs have burst through the skin, ready to sting any attacker.
And what they discovered is even more gruesome than they imagined.