Chimps have ‘police,’ too

A baby chimpanzee riding on its mother's back

A group of chimps crossing a stream

Chimpanzees live in groups that range in size from 15 to 150 members, although individuals travel and forage (look for food in the forest) in much smaller groups during the day. Chimps lives in male-dominated groups with strict rules, where disputes (conflicts, fights) are generally settled without the need for violence.

Scientists have revealed that certain members in a chimpanzee group act as an impartial “police” (they don't take sides) to mediate conflicts and preserve peace, Science Daily and livescience.com reported Wednesday.

Animal groups handle conflicts in a variety of ways, but the arbiters (referees, judges) in chimps, gorillas, orangutans and other primate groups were neither biased nor aggressive. The arbiters did not support allies (friends) or punish wrongdoers.

Primatologists (scientists who study apes, monkeys etc.) from the University of Zurich in Switzerland analyzed four different chimpanzee groups for nearly 600 hours over two years.

During this time, the introduction of new females caused rifts (differences, conflicts) within the groups, causing power struggles.

Scientists watched the social interactions and conflicts and found that certain individuals, usually a high-ranking (important and powerful) male or female, acted as peacemakers.

The researchers first thought that high-ranking “police” members wanted to keep themselves dominant (the most powerful) or wanted to prevent potential mates from leaving the group.

In order for this hypothesis (possible scientific explanation) to be true, however, all policing apes needed to be males, because female chimps do not fight over ranks (who has power and control) and female members are the most likely to leave the group. In contrast, the policing behavior was found in both sexes.

Also, the arbitrators were more likely to intervene (try to stop fights) when conflict within the group was larger and more members of the group were involved.

This caused scientists to believe the reason for police chimps is the stability (peaceful togetherness) of group. Ending  quarrels (arguments) usually leads to a healthy living environment for the primates.

"The interest in community concern (caring about the well-being of others) that is highly developed in us humans and forms the basis for our moral behavior (how we treat other people) is deeply rooted (old and strong). It can also be observed in our closest relatives (primates such as chimpanzees and gorillas)," explained Claudia Rudolf von Rohr, the lead author of the study.

Vocabulary:

impartial: not taking sides in a fight or conflict
biased: the opposite of impartial; taking sides
primatologists: scientists who study primates (primates are chimpanzees, gorillas etc.)
arbiter: someone who acts as a referee or judge to help stop a conflict; a negotiator
rift: a division or conflict
arbitrators: similar to arbiters