Ranking male baboons recover quickly from injuries

Washington, May 23 (IANS) Surprisingly, high-ranking male baboons recover more quickly from injuries and are less likely to become ill than other males, says a new study.

Notre Dame biologist Beth Archie, with Jeanne Altmann from Princeton and Susan Alberts from Duke Universities, examined health records from the Amboseli Baboon Research Project in Kenya.

They found that high rank is associated with faster wound healing. The finding is somewhat surprising, given that top-ranked males also experience high stress, which should suppress immune responses, said a university statement.

"In humans and animals, it has always been a big debate whether the stress of being on top is better or worse than the stress of being on the bottom," said Archie, who led the study.

"Our results suggest that, while animals in both positions experience stress, several factors that go along with high rank might serve to protect males from the negative effects of stress," Archie said.

Researchers examined 27 years of data on naturally occurring illness and injuries in wild male baboons, which is a notably large data set.

Although research of health and disease in animals in lab settings has been quite extensive, this study is one of most comprehensive ever conducted on animals in a natural setting.

Previous research found that high testosterone levels and intense reproductive efforts can suppress immune function and are highest among high-ranking males.

However, Archie and colleagues found that high-ranking males were less likely to become ill and recovered faster from injuries and illnesses than low-ranking males.

The authors suggest that chronic stress, old age and poor physical condition tied with low rank may suppress immune function in low-ranking males.