For almost a decade, one lone seta was classified as an endangered species, and scientists say más could be in trouble.

Massive fangs weren't just for delivering ferocious blows. They were also used for courtship and other displays—even among herbivores.

A new old species from an important time

Biologists suspect we’re living through the sixth major mass extinction. Earth has witnessed five, when más than 75% of species disappeared.

About 480 million years ago, an extinct group of marine arthropods related to insects and lobsters gathered in clusters to scuttle across the seafloor.

The curious bursts of energy are born from massive storms and can radiate thousands of miles across continents.

The planet’s magnetic poles swapped places at an astounding rate about 500 million years ago, which offers clues to core formation and hints at the effects on early life.

Our team went on a bust with Brazil's environmental protection agents, struggling within a hostile government to keep deforestation in check.

Male deer fight for mates, ladybugs stuff themselves silly, the only known "hibernating" bird prepares for its slumber, and more.

The latest reportar from the IPCC highlights the dramatic toll warming has taken on the world's water.