Evolution

An analysis of 391 skulls shows that birds evolved surprisingly slowly, compared with their dinosaur forerunners

Researchers found extra bones within a 240-million-year-old ichthyosaur fossil—which they determined to be the ichthyosaur’s last, possibly fatal meal. Christopher Intagliata reports.

Butterflies, fish and frogs sport rear-end eyespots that reduce predation. Painting eye markings on cows similarly seems to ward off predators.

Hermit warblers in California have developed 35 different song dialects, apparently as a result of wildfires temporarily driving them out of certain areas.

A rare cracked fossil shows the world through ancient eyes

Scientists spotted a mouse at the summit of Llullaillaco, a 22,000-foot-tall volcano on the border of Chile and Argentina. Julia Rosen reports.

Originally published in June 1894

Rather than undergoing active chameleonlike color changes, glass frogs’ translucency allows light to bounce from their background and go through them—making their apparent color close to their setting.  

Experts explain how radiometric dating allows them to reconstruct ancient time lines

Cooperation made Homo sapiens the last human species standing

Newly analyzed remains depict the scope of a devastating event

Genomes and fossils reveal their remarkable evolutionary history