Why Some Wild Animals Are Becoming Nicer

Nature is supposed to be red in tooth and claw, and domestication an artificial process for making animals gentle. But it appears that some corners of the animal kingdom are becoming kinder, gentler places. Certain creatures may be domesticating themselves.

This possibility is most apparent in bonobos, a close cousin of chimpanzees. Unlike their violent cousins, bonobos are generally peaceful. And while many animals have evolved to be socially agreeable, bonobos — and possibly other species — seem to be experiencing something more precise and profound: the physical and behavioral changes specifically described in studies of domestication, but as a natural evolutionary process.

“Normally you think of domestication as something that happens at the hands of humans,” said Brian Hare, a Duke University evolutionary anthropologist and co-author of a bonobo research review published Jan. 20 in Animal Behaviour. “The idea that a species domesticated itself is a bit crazy, but there are some species that outcompeted others by becoming nicer.”

The essence of domestication is a loss of aggression. Because this is such a basic trait, involving modifications to nervous and endocrine systems, and alterations of complex gene networks with multiple functions, it generates a variety of changes. Researchers call them a “domestication syndrome,” and while aspects are seen in all domesticated animals, the principles are distilled in a famous Russian experiment on foxes.

Starting in 1959 with 130 farm-bred but wild foxes and continuing until today, researchers allowed only those individuals most tolerant of human contact to breed. In less than 50 years, the fierce-tempered and untouchable foxes became playful, face-licking sweethearts who loved to be held. Those traits are typically seen in wild pups, but disappear as they grow up. [continue]