Posted by:
jfmoore
at Thu Dec 4 01:47:37 2003 [ Email Message ] [ Show All Posts by jfmoore ]
Yes, snakes most definitely can move their eyes. And all the ones I’ve observed can move each eyeball independently of the other. If you’ll look at a snake at rest in a cage (one not distracted by you or anything else), you’ll probably be able to observe that it often has one eye pointed forward and one back; or one oriented upward and one downward. Seems like a fairly obvious advantage for being on the lookout for predator or prey.
Perhaps you’re thinking of the immovable spectacle which covers the eye. What were moveable eyelids in the long ago ancestors of snakes (and which persist in most lizards today) have through evolution fused to become the tough, clear protective scale we can observe when the snake sheds its skin. Actually, in the “ontogeny recapitulates phylogeny” vein, this process occurs during development of every snake in its egg. That is, a ring of tissue around the edge of each eye grows inward until it meets in the middle and fuses.
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