Male genitals grow longer with more competition from other males.

Birth control disrupts female odors used in mating and other social situations.

A mathematical analysis shows that random factors underlie the insects’ movements across the landscape.

BLOG: Sphagnum reproduces with a bang that compensates for life so close to the ground.

Jumping preceded mastery of the touchdown in amphibian evolution, a new study suggests.

A fossil jaw may, or may not, come from the oldest known example of man’s best friend.

A crawling caterpillar’s gut moves forward before the rest of its body does.

Clueless larvae don’t heed the scent of nonnative turtles, giving newcomers an edge over native species, a European study finds.

Mouse breath triggers special cells in the nose that help send a safe-to-eat message. (p. 10)

Pancake batfishes may be getting oiled before they get named. (p. 10)

A 29- to 28-million-year-old primate fossil found in Saudi Arabia assists scientists in timing a major evolutionary transition. (p. 11)

Biologists test the pros of amphibian athletics. (p. 11)

Left intact, dense swaths of trees can reduce tsunami damage, a new study suggests.

Rising carbon dioxide alters fish larvae’s sense of smell, which they use to avoid predators and find their way home.