When confronted, men react either as bonobos or chimps

Washington, June 29 (ANI): Prior to competition, an average man undergoes hormonal changes similar to a passive bonobo, but those striving for status behave more like chimpanzees, according to a new study.

While chimps live in male-dominated societies where status is paramount and aggression can be severe, bonobos are a lot more flexible.

The study revealed that male chimpanzees showed an increase in testosterone, which is thought to prepare animals for competition or aggressive interactions. By contrast, male bonobos showed an increase in cortisol, which is associated with stress and more passive social strategies in other animals.

"These results suggest that the steroid hormone shifts that are correlated with the competitive drive of men are shared through descent with other apes," said Victoria Wobber, a Harvard graduate student and first author of the study.

Something unique about human males is that after competition they experience an increase in testosterone if they win or a decrease in testosterone if they lose - a phenomenon unseen in chimps and bonobos.

"It's exciting because we can see that in some ways we're similar to bonobos, in others we're similar to chimpanzees," said Duke anthropologist Brian Hare, co-author.

"But then there's also a part of our biology that seems to be entirely unique."

The study is published in Proceedings of the National Academy of Sciences. (ANI)