Millions of years ago, the ancestor of modern rattlesnakes was endowed with a genetic arsenal of toxic weaponry. But in a relatively short period of evolutionary time, different types of snakes kept different types of toxin genes, and shed others.
Millions of years ago, the ancestor of modern rattlesnakes was endowed with a genetic arsenal of toxic weaponry. But in a relatively short period of evolutionary time, different types of snakes kept different types of toxin genes, and shed others.