Swimming from Africa to Australia and back, a great white shark completed the first documented round-trip ocean crossing by a shark—and in record time.

Giant marine reptiles called plesiosaurs used their long necks to hunt for food on the seabed, newly found fossils suggest. The discovery challenges the long-held idea that the ocean predators targeted only free-swimming prey.

A huge Burmese python in Florida may have died while eating an alligator. But a new theory says it was a battle with a second gator that made the snake explode. Updated.

Scientists in China have found fossils of two new flying reptile species that lived during the dinosaur era.

To fight an invasive bug that's devastating hemlock trees in Appalachia, scientists are siccing other alien insects on the offender.

The winning pictures in this year's Visions of Science Photographic Awards take you from the depths of the Caribbean Sea to the surface of a cancer cell.

In a discovery with echoes of Jurassic Park, a scientist has found a 20 million-year-old fossil of a spider—and its blood—trapped in amber. It's the first such find of its kind.

Humans and other mammals have flourished on the Earth, and a study says one important change in their environment may help explain why: a large increase in the concentration of atmospheric oxygen.

Bovine tuberculosis poses a growing threat to South Africa's free-ranging lion population, says the chief veterinarian for Kruger National Park.

South Dakota's inaugural cougar hunting season begins Saturday. Is it a managed recreational opportunity or a threat to big cat survival?

Researchers have photographed wild gorillas using sticks to navigate a swampy clearing in Africa. The images provide the first documented use of tools among wild gorillas.

Female barn swallows will cheat on their mates with males that have more colorful plumage, according to a new sexual behavior study.

From aggressive dogs to nervous apes, pharmacological control of behavior problems has become a routine part of veterinary medicine.

Data about the evolution of tiny crustaceans called whale lice can reveal useful facts about the history of right whales.

The first-ever images of a living giant squid in the wild have been captured by Japanese scientists.