`New research reveals that monkey cops help keep social groups in line.
Not having guns or nightsticks, they leverage their group seniority, craft intimidating reputations and count on good voter turnout.
Take the primate police out of a group, as researchers did, and the rest get more violent and aggressive. Interaction between cliques drops significantly. [..]
The study, detailed in today’s issue of the journal Nature, also uncovered a complex monkey “voting” system for appointing the peacekeepers.’