One of the most distinctive features of turtles is their shell, which is actually part of their skeleton ... also an integral ...

Basically, a turtle's skeleton is inside out. And just like you can't take a skeleton out of a person, right, you can't take a turtle out of its shell either. But if you could, you'd probably be ...

The way that turtles evolved into their modern form, with a shell fused to their skeleton and a beaklike face without teeth, has been described as “one of evolution’s most enduring puzzles”.