An argument breaks out and a brash young upstart tosses a barb at the grande dame. A hush falls over the crowd as everyone turns to look.

This isn't a commotion at a high-society cocktail party, but the reaction to an upset in social order among a cluster of baboons. Yes, baboons.

It turns out that baboons, like people, not only depend on elaborate social structures, they also appear to be keenly aware of them. In two studies appearing this week in Science, researchers show social bonds are critical among female baboons in promoting the health of their young and the animals are very aware of who's who and what interactions matter.

The findings have implications for our understanding of why humans behave the way we do, the scientists say.

"Humans are very aware of status and alliances," said Dorothy Cheney, a biologist at the University of Pennsylvania in Philadelphia. "What this work suggests is this ability to recognize dominance, rank and kinship of others — and perhaps even the ability to manipulate that order — may be very old behavior, evolutionarily speaking."

Stirring Trouble

While spats between people might take the form of harsh exchanges or perhaps even slaps or punches, disputes among female baboons almost always transpire as grunts and screams. A dominant baboon grunts her displeasure while a submissive one screams in response. Male baboons, meanwhile, are more likely to get physical. In the first study, Cheney decided to focus on female baboon interactions since they were easy to mimic and influence.

Cheney worked with Penn graduate student Thore Bergman to record grunts and screams from 19 individual female baboons. Using a computer program, they then spliced combinations of grunts and screams to create interactions that would otherwise be rare in the wild.

For example, they took a recording of dominant grunting by a female from a low-ranking family and spliced it with a recording of submissive screaming by a high-ranking female.

They also toyed with family hierarchies. In baboon female groups, the mother rules while the youngest daughter oddly carries greater status than her older sisters. Scientists believe this might be associated with the fact that mothers defend their youngest first since they are most vulnerable.

To upset this order, Cheney and Bergman spliced together grunts from an older, normally submissive sister with screams from her younger, normally dominant sister.

The team then played these doctored recordings from a hidden location near female baboon groups and watched for reactions.

"The biggest responses we got were definitely about social structure," said Bergman, who authored the study.

In-family fights would draw stares of a couple seconds or more, while fights between different families would draw long stares of 10-12 seconds. That, apparently, is a big reaction from these large, social primates.

"Baboons tend to be pretty laid-back," explained Bergman.

Rst of Article