Evolution

A bitten bone shows how a young tyrannosaur fed

Thyroid hormone, which helps warm-blooded animals regulate body temperature, also appears to put a halt on heart regeneration. Christopher Intagliata reports.

Excavations of stone tools left behind by nonhuman primates are illuminating the origins of technological innovation

Psychiatrist Randolph Nesse, one of the founders of evolutionary medicine, explains why natural selection did not rid our species of onerous psychiatric disorders

Bones uncovered in Arizona help fill a gap in the great amphibian backstory

On the national park's 100th anniversary, a South African–born geologist recalls his first encounter with a spectacular natural wonder

Researchers say they found evidence life began moving 2.1 billion years ago, but that contentious conclusion is far from certain

Grandmothers can enhance the survival of grandchildren. That is, unless grandma’s too old or lives too far away. Karen Hopkin reports.

An asteroid impact and volcanoes acting together could have done in the beasts, new rock dates indicate

The partial skull and additional bones represent a dinosaur species never found before

A new genetic study of Latin Americans provides evidence that gene variants for lighter skin color came about in Asia as well as in Europe. Christopher Intagliata reports.

The fossilized print, found in Gibraltar, is said to date to 28,000 years ago, which might mean it belonged to a Neandertal. But not everyone agrees with that interpretation