Top ranking baboons, maybe humans, more stressed than known

Kathleen Blanchard's picture
Alpha baboons and stress
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It's no secret that being the boss can be stressful from increased responsibility. Princeton researchers studied stress hormone levels of top ranking baboons to discover they experience more stress than previously known. The result, if translated to humans, could have implications for understanding how psychological and physical stress negatively impacts human health.

According to study, published in the July 15 issue of the journal Science, baboon behavior mimics that of humans. They live in complex environments and have social hierarchies. In the research, scientists found alpha baboon have much higher levels of stress hormones than beta males who rank below them. The significance of the finding is that the hormone levels were present even during periods of stability.

According to Laurence Gesquiere, an associate research scholar in Princeton's Department of Ecology and Evolutionary Biology,

"An important insight from our study is that the top position in some animal -- and possibly human -- societies has unique costs and benefits associated with it, ones that may persist both when social orders experience some major perturbations as well as when they are stable."

Nine year study looks at stress from being the boss

The study took place over a nine year period. Researchers consistently measured glucocorticoid and testosterone in fecal samples over the study period.

Alpha males had less testosterone and higher glucocorticoid levels than beta males, with the exception of those at the very top who had higher levels of both.

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Because of the duration of the study, researchers say they were able to control for variables that could otherwise prevent accuracy.

study co-author and Duke University biology professor Susan Alberts said:

"We've known for decades that alpha males have an advantage in reproduction, but these results show that life at the top has a real downside, and that being an alpha male comes at a real cost."

Jeanne Altmann, Princeton's Eugene Higgins Professor of Ecology and Evolutionary Biology Emeritus and colleagues have been studying baboons living in in Kenya's Amboseli Basin for 40 years. She says, "Humans also live in stratified societies, and social status is well known to be associated with some but not all health outcomes in humans.”

The researchers say the study has health implications for humans. Baboons physically fight and are responsible for guarding females, leading to higher energy expenditure than alpha human males.

But, Gesquiere and Alberts also say there is little difference between baboons and humans when it comes to psychological stressors associated with maintaining alpha status. The researchers say more studies are needed to understand the impact of higher social status, stress and health outcomes in humans.

"Science": Life at the Top: Rank and Stress in Wild Male Baboons
Laurence Gesquiere, et al.; July 15, 2001
DOI: 10.1126/science.1207120

Image credit: Wikimedia Commons
Author: Nicholas M. Perrault

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