He began to see a strong correlation between where guppies lived in a particular stream and whether the fish were bright or drab. But what was responsible for these trends in coloration?

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 ...

Last in a series. As Scott slowly recovered from distemper, he began to eat on his own and even play. It was a huge relief; my best friend was going to be OK. To my parents, though, he was "a dog." ...