From Science News:
How the snake got its fangs
By Amy Maxmen
July 30th, 2008
“How’d you get those newfangled teeth?” hissed the petite garter snake to the venomous cobra. “Same way that you got yours,” cobra replied. All fangs — no matter their size, shape or position — descend from a single evolutionary event, new evidence from snake embryos suggests. …
The new study, led by Freek Vonk of Leiden University in The Netherlands, reveals that snakes didn’t reinvent the wheel with each new version of their venom-delivery systems. The report appears in the July 31 Nature.
Rapid venom evolution in pit vipers may be defensive: here.
Garter snake photo: here.
Eastern garter snake: here.