Plenty of social animals have ways to police each other's behavior — so that if an animal enters the wrong territory or reproduces when it's not supposed to, it's punished. But researchers have found that banded mongooses have a more repressive system, which forces all females to give birth at the same time. Or else.
Sadly, this news doesn't involve chimps wearing badges and shooting criminals... at least, not yet. But our fellow primates do display behaviors much like a human cop, as respected members of chimp populations will intervene in conflicts as an impartial peacekeepers.