Turtle shells evolved over the course of 300 million years, but self-defense wasn't the initial driver, researchers think. When you purchase through links on our site, we may earn an affiliate ...

Turtles and tortoises are both reptiles with shells, so what exactly are their differences? When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works.

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 ...