Animals

For decades, researchers have commonly assumed that higher oxygen levels led to the sudden diversification of animal life 540 million years ago. But one iconoclast argues the opposite: that new animal behaviors raised oxygen levels and remade the environment.

An unlikely team offers a controversial hypothesis about what enabled animal life to get more complex during the Cambrian explosion.

Game theorists have developed a new model of communication among animals. It suggests evolution will produce a situation in which members of a species are honest most of the time, but not always.