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 ...

A 260 million-year-old fossil has been determined to be the oldest ancestor of turtles found to date, revealing something about the reptile's mysterious past. Michelle Starr is CNET's science editor, ...

When you buy through links on our articles, Future and its syndication partners may earn a commission. The broad-shelled river turtle (Chelodina expansa) falls into a group known as side-neck turtles.