Human societies rapidly descend into anarchy and chaos without policing. Now, researchers have found that the same thing happens when groups of monkeys are left to their own devices instead of being “policed” by dominant males.
It was already well known that in groups of pigtailed macaques (Macaca nemestrina), dominant males keep the rest in order through a form of policing. As they patrol the herd, they frequently receive peaceful “bared teeth” signals from other, subordinate monkeys, acknowledging that the dominant male is in charge. The “police” macaques often intervene to defuse scuffles before they can escalate.
To find out what happens when the primate police are missing, Jessica Flack of the Santa Fe Institute in New Mexico, US, and her colleagues temporarily removed three of four dominant males simultaneously from a captive group of 84 pigtailed macaques at the Yerkes National Primate Research Center, near Lawrenceville, Georgia, US.