A turtle can’t crawl out of its shell. In fact, the shell is actually part of a turtle’s skeleton, as much of our ribcage is of ours. But if you could peer inside a shell, you’d find some of the most unusual features in the animal kingdom, such as a butt- err, cloaca, that some species use to breathe underwater. Did you know that turtles can actually breathe through their rear ends? Neither did we! Let's learn more. A turtle's shell includes bones and nerve endings that it needs to live and fun…