A complain of monkey

The report in Primate Journal proposes that males commit infanticide due to sexual competition between the males in the group. If there are too many new males, the competition would only get worse.

The study also suggests that their observations could now explain the female-biased sex ratios that spider monkeys groups are known to have.In one case, a male was observed being violent towards a mother, named Kuao, with a young baby. Although no aggression was observed towards the child at that time, seven days later he was found crying on the forest floor with many cuts and open wounds. A day later he died from his injuries. The killer was never identified.