I am curious about the tails of boas and pythons. I notice that a lot of them have the small tail following a wide body. I find this very awkward-looking and am curious as to what family or division of the snakes is this limited to or is it all-encompasing? I was thinking about getting a BP or some sort of boid, but didn't realize BPs have this disproportionately small tail.

What is the evolutionary purpose of it?