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Dmmetler
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Random snake question: I was reading ahead in science about evolution and vestigial structures.  Do snakes retain leg bones in their bodies?   Are they evolved from lizards who had an advantage by being low to the ground?  

 

Yes on vestigial limbs, for some snakes. You can see it most in the heavier bodied pythons and boas (who are also closest to the snakes in the early fossil record), where the skeleton still shows signs of limb attachment points, and the pelvis has short "spurs" attached. On male pythons, these actually protrude out of the body slightly, and are visible (although tiny compared to the snake. On a 15 foot male Burmese python, they might be, maybe, an inch long, on DD's 5 foot male Ball python, they're maybe a couple of millimeters).

 

No on evolving from lizards, at least this week. It's one of those "which came first" questions that the fossil record keeps shaking up, but as of right now, it looks like snakes and lizards are a case of parallel tracks, and any relation between them dates back to early primeval oceanic vertebrates.

 

Herpetology is kind of the catch-all category of the biological world, with a lot of animals where the only commonality is that they breathe air, have a backbone, and are cold-blooded. 

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No on evolving from lizards, at least this week. It's one of those "which came first" questions that the fossil record keeps shaking up, but as of right now, it looks like snakes and lizards are a case of parallel tracks, and any relation between them dates back to early primeval oceanic vertebrates.

 

 

It is kind of funny to think about how losing one's limbs could be a survival advantage.  It's like saying, "my life would be so much easier, if only I were a quadruple amputee."  

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It is kind of funny to think about how losing one's limbs could be a survival advantage.  It's like saying, "my life would be so much easier, if only I were a quadruple amputee."  

 

Harry Greene has a really, really neat book on the evolution of snakes along with hominids. Basically, every time hominids made a leap in tool use, snakes made a leap in adapting to them (the talk we heard was on evolution of spitting venom-it evolved separately on several continents, and in all cases, happened as hominids evolved distance weaponry. In areas where tree cover or landforms made slings or arrows less viable, snakes didn't evolve their own form of distance weaponry (and snakes, invariably, aim for the eyes in spitting-which allows them to escape. They don't use spitting venom to kill prey at all-it's a defensive strategy). It's really, really cool.

 

As far as the limbless thing, snakes are more adept climbers with a larger body mass than lizards, so that larger surface area and the ability to use those muscles really does seem to make a difference. Rat snakes can pretty much climb straight up a tree trunk, something that usually only fairly small legged creatures can do.

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