When evolutionary biologist John Endler began studying Trinidad's wild guppies in the 1970s, he was struck by the wide variation among guppies from different streams, even among guppies living in ...

In a simulation or in the wild, where predators are plentiful, male guppies become increasingly drab over generations, pushed by predation pressure toward greater camouflage. So if camouflage ...

Researchers caught and observed 3,600 wild guppies that were exposed to different concentrations of fluoxetine over five ...