Chimps with higher-ranking moms more likely to win a fight

Chuck Bednar for redOrbit.com – Your Universe Online

When two kids get into a verbal sparring match on the playground, they often taunt each other about how tough their respective dads are, but when it comes to chimps, new research indicates that success in a fight tends to be more dependent upon the moms.

In the February 2015 edition of the journal Animal Behaviour, scientists from the Jane Goodall Institute Research Center at Duke University and their colleagues explained that, in fights taking place between young chimpanzees living in East Africa, those who had higher-ranked mothers were more likely to emerge victorious.

The research involved 12 years worth of observations of playground-style fights between chimps living at the Gombe National Park in western Tanzania. Those field notes, which were collected between 2000 and 2011, were part of a larger database containing over 50 years worth of data on 300 wild chimpanzees data all the way back to the early 1960s, the study authors said.

Young chimps, just like human children, are often subjected to teasing, taunting and bullying during their playtime, and lead author Catherine Markham, an assistant professor at Stony Brook University, said that they wanted to discover the role that mothers play in helping their offspring establish dominance within their peer groups.

During the course of their investigation, chimpanzees under the age of 12 engaged in nearly 140 total fights, most of them between non-siblings. Winners of each skirmish were declared based on which chimp was the primary aggressor (doing most of the hitting, kicking, biting or chasing) as well as which one squealed, cried or ran away and the end of the conflict.

When they compared the results of those fights with the parental pecking order amongst the chimps, they found that those who had higher-ranking mothers were more likely to win. They also found that higher-ranking chimp moms were not overprotective helicopter parents – in fact, they were no more meddlesome than lower-ranking moms, according to the authors.

“In other primate species you see moms swooping in to intervene and help their offspring,” said co-author Carson Murray of George Washington University. However, chimp moms let their kids fight their own battles 90 percent of the time, intervening in just 10 out of 137 battles.

Markham said that it could be that the mere threat of a nearby “bodyguard” is enough to explain the phenomenon, or that it could be that “offspring of higher-ranking moms are bigger or stronger for their age, either because they and their moms had priority access to food or because the same genetics that made their moms high-ranking give them a competitive advantage, too.”

The next step, the researchers noted, will be to compare the outcomes of fights when the mother is nearby to those when she is further away. Murray said that it is possible that young chimps are “more bold or confident or their opponents are more scared when the moms are close.”

The research, which was supported by grants from the National Science Foundation (NSF), the National Institutes of Health (NIH) and the Leo S. Guthman Foundation, could help explain why the offspring of higher-ranking chimpanzee females are more likely to survive. That pattern was first discovered by Anne Pusey, chair of evolutionary anthropology at Duke, in the late 1990s.

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