Male baboons are more prone to commit violence against infants and pregnant mothers when there are fewer cycling females available. Photo by Catherine Markham/Stony Brook University
Jan. 18 (UPI) -- Why do some male baboons commit domestic abuse? Simply put: they're desperate.
In any given year, most male baboons won't commit violence against females. But domestic abuse does happen, and new research suggests it is more likely to happen when fewer females are cycling, or in heat.
"In situations where males have few opportunities, they resort to violence to achieve what's necessary to survive and reproduce," Matthew Zipple, a grad student at Duke University, said in a news release. "When reproductive opportunities abound, this behavior is less frequent."
While surveying baboon census records collected in Kenya's Amboseli National Park in southern Kenya between 1978 and 2015, researchers noticed infanticide and miscarriage numbers spiked in the two weeks following the arrival of new male.
Scientists found male newcomers were responsible for 6 percent of miscarriages and 2 percent of infant deaths. But those numbers tripled when cycling females were scarce.
Researchers also determined males who forgo patience for violence -- attacking infants and pregnant mothers -- have to wait shorter amounts of time to mate. Perpetrators often end up mating with the mothers of their victims.
Males who quickly climbed the rungs of the social ladder were more likely to enact violence than those lower down.
During food shortages, baboon populations spread out, and females take longer in between pregnancies. If males choose not to resort to violence, they must wait longer than usual to sire their next round of offspring.
"It's not just who they are, it's the circumstances they find themselves in that makes the difference," Zipple said.
Researchers shared their analysis of domestic abuse among baboons in the journal Proceedings of the Royal Society B.