The Loh Down On Science

Fang Fever

Researcher Freek Vonk finds the evolutionary origins of all snake fangs.

Fangs for the memories!

This is Sandra Tsing Loh with The Loh Down on Science.

Over two thirds of the world's snakes have venomous fangs. Some have them in front--like rattlesnakes, cobras, and vipers--for snagging quick dangerous prey, like rats. Sometimes they're in back, as in grass snakes, which hunt milder meals.

Both fangs date back about twenty-four million years. But how did the two types evolve?

Enter Freek Vonk of Leiden University in The Netherlands.

Vonk studied embryos of eight different fanged snake species, focusing on a gene triggering dental development. He noticed that in ALL unborn snakes, fang formation begins in the rear of the mouth.

As the upper jaw develops, fangs move forward, or stay put, depending on the species.

His study suggests that both types of fangs evolved from a common origin. The key? Detached rear dental tissue -- unique to fanged snakes. The upper tooth row develops in two separate pieces. This allowed each species, over evolutionary time, to develop the front- or back-fang option, depending on dietary needs.

No word on the middle fang. But I know it's there somewhere, I do! Help us, Freek Vonk.


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