For years, people have understood them to be at imminent risk of extinction, despite evidence to the contrary. Why?

Scenes from our national parks

Bristle worms reproduce at the same hour every month. How do they do it?

In its ideal form, a contraceptive vaccine could prevent pregnancy without the messy side effects of some hormonal birth control.

Prion diseases are poorly understood, and this one is devastating.

Rising temperatures are releasing mercury into the Arctic.

The insects’ sweet tooth should have made them easy to kill. But they outsmarted us with warp-speed evolution.

Wouldn’t you love to try it?

A newly identified species upends the theory that the dinosaurs were already dying before the asteroid.