When I was younger, so much younger than today, we had a tortoise as a pet. In tribute to the great mathematician of ancient Greece, we named him Archimedes, Archie for short. He was a charmer, ...

It's a long-held idea that turtles can tuck their heads into their shells when threatened. But is it true? And is this protective trick why turtles the world over have shells today? The answer is that ...