How snakes got their fangs

HOW did snakes evolve one of nature's most complex bioweapons, the snake fang and its associated venom gland? The origin of the fang has been a puzzle, but now it seems this weapon may have evolved as a result of a simple embryological change.

Vipers and cobras both have large, hollow fangs at the front of their mouth, while other snakes have fangs at the back, and some have no fangs at all. Vipers and cobras are only distantly related, suggesting their fangs evolved independently, yet it strains credulity that such a sophisticated system should have evolved twice. A huge controversy in snake evolution has been whether these groups' front fangs, and indeed front and rear fangs generally, share the same origin.

To try to resolve the mystery, Freek Vonk of Leiden University in the Netherlands and colleagues studied the embryological development of the teeth on the upper jaw