Turtles may crawl out of their shells in cartoons, but not in real life. A turtle’s backbone is built into the top of its shell, which is called the carapace. When threatened, a turtle often pulls in its head, tail and legs for protection.

In some species, the bottom part of the shell (called the plastron) is hinged, forming such a tight closure that not even a knife can pry the two halves open. This adaptation helps many turtles to live 50 years or more in the wild. In captivity, turtles can live even longer, with some reaching more than 100 years old!