For macaques, male bonding is a political move

November 18, 2010
Rhesus macaque

Contrary to expectations, new evidence shows that unrelated male macaques in the wild form close and stable social partnerships with select males in their groups. Although the degree of emotional attachment obviously can't be measured, those relationships resemble human friendship, according to researchers who report their findings online on Nov. 18 in Current Biology, a Cell Press publication. What's more, it appears the motivation for those males to maintain close ties with other males is political in nature.

"We were able to show that the benefit of social bonding accrues through 'the manipulation of ones' own and others' social relationships,' which is one definition of politics," said Oliver Schülke of Georg August University Göttingen in Germany. "The bond does not directly affect access to desirable resources but helps males to climb up the social ladder and to stay up there at the cost of other males that lose their status."

Earlier evidence had shown that female animals live longer and have more offspring when they form strong bonds with other females. The benefit of friendship in the case of females is usually explained by greater access to food and safety. But, given the strong competition among males for access to mates, scientists had generally expected that evolutionary forces would work against male bonding, particularly in groups like those of the , in which male members typically aren't close kin.

In the current study, Schülke and his colleague Julia Ostner focused on wild male Assamese macaques living in their natural environment in Thailand. They found that males do maintain with other males in which both members spend time together and groom one another. Those bonds aren't confined to potential kin.

Males with stronger bonds to other males tended to form coalitions, and those coalitions predicted future social dominance, the researchers report. The strength of males' social bonds was directly linked to the number of offspring they sired.

"We have shown for the first time that having close friends makes males more successful in terms of social status and paternity," Ostner said.

The researchers added that they are "quite confident" that it is not the other way around—that successful males attract more friends. "The effect of friendship on success materializes in the future," they said. "Success does not make for future friendships."

Schülke and Ostner said that earlier work in chimpanzees starting with Jane Goodall had shown that strong bonds among males promote alliance formation in conflicts over status. But, they said, chimps are different from macaques in that they stay in their natal groups all their lives, often bonding with brothers or at least with other males that they are sure to live with for long periods of time. On the other hand, male macaques all leave the groups they are born into sooner or later, resulting in a male society that is much more fluid.

The researchers expect that their findings will apply to other species, in cases in which males live in large groups with many males for long enough to develop bonds and benefit from them. The findings in primates may also provide insight into our own social lives.

"Our results suggest that the universal tendency of humans to form close social ties has evolutionary roots outside the extended family," the researchers said. "This long evolutionary history of a fundamental social trait may also explain why the loss of friendship or social integration has severe consequences for human mental and physical health."

Explore further: Sexual harassment from males prevents female bonding, says study

Related Stories

Fighting for their attention

April 4, 2007

Mating strategies are straightforward in bottlenose dolphins, or are they? Much of the work carried on male-female relationships in that species to date show that males tend to coerce females who are left with little choice ...

Females decide whether ambitious males float or flounder

January 30, 2008

Aggression, testosterone and nepotism don’t necessarily help one climb the social ladder, but the support of a good female can, according to new research on the social habits of an unusual African species of fish.

Females avoid incest by causing male relatives to leave home

August 15, 2007

Researchers at the University of Sheffield in the UK and Leibniz Institute for Zoo and Wildlife Research (IZW) in Berlin, Germany, have found that female hyenas avoid inbreeding with their male relatives by giving them little ...

Mating that causes injuries

February 20, 2009

Researchers at Uppsala University can now show that what is good for one sex is not always good for the other sex. In fact, evolutionary conflicts between the two sexes cause characteristics and behaviors that are downright ...

Recommended for you

Mammal long thought extinct in Australia resurfaces

December 15, 2017

A crest-tailed mulgara, a small carnivorous marsupial known only from fossilised bone fragments and presumed extinct in NSW for more than century, has been discovered in Sturt National Park north-west of Tibooburra.

Finding a lethal parasite's vulnerabilities

December 15, 2017

An estimated 100 million people around the world are infected with Strongyloides stercoralis, a parasitic nematode, yet it's likely that many don't know it. The infection can persist for years, usually only causing mild symptoms. ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.