Shell-cracking turtles defied mass extinction at the end of the Cretaceous period

The mass extinction at the boundary between the Cretaceous and Paleogene periods was catastrophic, wiping out much of life on Earth. Vertebrate groups that dominated at the time, such as dinosaurs and many large marine reptiles, fell victim to the effects of the asteroid impact about 66 million years ago. However, the catastrophe did not affect all organisms to the same extent: turtles, for example, survived with only minimal losses. Their chance of survival was apparently linked to their diet: species with a preference for hard-shelled organisms survived the catastrophic event.