In Argentina, the return of pumas brought top predators back to the landscape — much to penguins’ dismay.

Off the coast of British Columbia, dolphins lead killer whales to salmon and earn their share of lunch, a new study reveals.

Jenny Carlson Donnelly traveled to malaria-affected countries to test mosquitoes and save lives. Then she lost her job at U.S.A.I.D.

© Cheriss May for The New York Times

A global treaty has extended trade protections to more than 70 shark and ray species whose numbers are in sharp decline.

© Matthew Abbott for The New York Times

Scientists and Indigenous sailors in the Marshall Islands are studying seafaring and the human brain.

The brilliant iridescent hues found in ammolite come from tiny air gaps in the fossils’ layers, a new study finds.

A pod of orcas in the Gulf of California has repeatedly hunted juvenile white sharks to feast on their livers.