Decoded: Why male baboons commit domestic violence

Scarcity of food or other resources may drive some baboon males to attack and kill infants of their own kind, a study has found.

The findings showed that some baboon males vying for a chance to father their own offspring expedite matters in a gruesome way -- they kill infants sired by other males and attack pregnant females, causing them to miscarry.

The behaviour reduces their waiting time to breed with pregnant and nursing females, who otherwise would not become sexually available again for up to a year.

"In situations where males have few opportunities, they resort to violence to achieve what's necessary to survive and reproduce. When reproductive opportunities abound, this behaviour is less frequent," said lead author Matthew Zipple, graduate student at Duke University in North Carolina, US.

Shortages of fertile females were particularly common in times of food scarcity, when baboon troops distance themselves from each other and females take 15 per cent longer between successive births -- which means males who don't kill have even longer to wait.

The perpetrators are more prone to commit domestic violence when forced to move into a group with few fertile females, Zipple added.

It was also more common when the incoming male achieved high social status very quickly, when he stayed in the group for three months or more or when there were many infants and pregnant females in the group.

"It's not just who they are, it's the circumstances they find themselves in that makes the difference," Zipple said.

In addition, the researchers found that immigrant males were responsible for roughly 2 per cent of infant deaths and 6 per cent of miscarriages between 1978 and 2015.

But when cycling females were few, the death rates more than tripled.

The findings come from a long-term study of wild baboons monitored on a near-daily basis since 1971 at Amboseli National Park in southern Kenya.

The study appeared online in the journal Proceedings of the Royal Society B.

--IANS

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