Turtle shells evolved over the course of 300 million years, but self-defense wasn't the initial driver, researchers think.

The earliest known ancestors of turtles appeared about 220–240 million years ago (in the late Triassic period), roughly the ...

There are many threats to sea turtles, but most of them come from humans. Dangers may range from getting entangled in fishing gear to losing their habitats from beach erosion and human development.