SEEING -RELIEVING- SCHEME : EVOLUTION ESSAY

COPYCAT CHIMPS : ' It's all just a matter of seeing and relieving and wondering about evolution..'

Ena Onishi, a doctoral student at Kyoto University in Japan, has spent over 600 hours watching  chimpanzees urinating. She has a good reason for all that peeping, though.

She is a part of team of researchers that recently discovered that the primate tend to tinkle when they see nearby chimps do the same.

In a study published in the journal Current Biology, Ms. Onishi and her team described this phenomenon, which they call contagious urination. Their discovery raises questions about the role  peeing might play in the social lives of chimps and other primates.

Ms. Onishi first spotted contagious urination in 2019 while observing chimps at the Kumamoto Sanctuary in Kyoto.

'' I was observing a group of captive chimpanzees for a different research project, and I noticed that they tended to urinate at the same time,'' Ms. Onishi said. '' It got me thinking, Could this be one of those contagious behaviours like contagious yawning? '' she explained, referring to our innate tendency to yawn upon seeing or hearing other people do the same.

Ms. Onishi studied the sanctuary's 20 chimpanzees, observing them peeing together over 1,300 times.  Ms. Onishi and her colleagues soon realized that the chimps were indeed urinating in rapid succession. 

They found that the nearer a chimp was to the initial urinator, the more likely it was to join the party.  They also discovered that chimps lower on the social ladder were more likely to go when others were going.

 '' The result was surprising for us,'' Ms. Onishi said. '' It raised intriguing questions about the social function of this behavior, which has been overlooked for a long time.''

Why the chimps do this remains a mystery, but Ms. Onishi and her colleagues have several hypotheses.

'' Contagious urination might help reinforce group connections, boosting overall social cohesion,'' she said.  '' It could promote a shared readiness for collective behaviors. There are so many possibilities.''

Although the study was limited to captive chimpanzees, the chances that this behavior is unique to this group are low.

'' If you walk with great apes in the wild, you often see that group members really coordinate what they're doing,'' said Martin Surbeck, an evolutionary biologist at Harvard University who was not involved in the research.

The World Students Society thanks Annie Roth.