Postanal

If you go back to chordate ancestry, where postanal tails were derived, they evolved to help in swimming. Then in amphibians they served to help swim and balance. With reptiles, again it helped balance (and in some helped swim and fight). Think ...

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... ape was a ground-dweller (the fossil record is pretty spotty on that lineage). Keep in mind, too, that only vertebrates officially have tails (postanal tails, at least), and these were originally for swimming.

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... things that classify chordates (lets see if I can remember them all). 1. notochord or spinal column (ie vertebra) 2. pharyngeal (gill) slits 3. Postanal tail http://embryo.soad.umich.edu/carnStages/stage14/10310lftLat.jpg Humans obviously have vertebrae. Do you see a neural ...

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Yes snakes do have tails. One of the caracteristic of all chordatas is that they have tail with postanal position. Therefor tail begins right after the anus and in most snakes it`s quite short (compare to the body length). In the legless lizards the tail is much longer ...

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