Pee is contagious among chimpanzees

Pee is contagious among chimpanzees

Megan Bartels Edited by Sarah Lewin Frazier

Some primates even pee together. Ena Onishi already knew that. Japanese even has a word for humans going to the bathroom together. connection. Still, Onishi became curious when he noticed the behavior of the chimpanzees he had observed when he was a doctoral student at the Kyoto University Wildlife Research Center. Although she knew about well-studied “contagious” behaviors such as human yawning, Chimpanzees may exhibit ‘contagious urination’.

In a new paper published on Monday, current biology, Onishi and his co-authors found that “monkeys see, monkeys do” indeed appears to apply to these chimpanzees (despite not being technically monkeys). Even more interestingly, each animal’s position in the social hierarchy seems to influence which animals pee and when. The authors say the discovery represents the first known scientific study of contagious urination.

“This is certainly not something I set out to study,” says Matthew Campbell, a psychologist at California State University, Channel Islands. Although he was not involved in the new study, he has been studying contagious behavior in chimpanzees. “I thought this was smart and novel, and it leads to a lot of interesting questions.”

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From 2019 to 2021, Onishi and his colleagues studied 20 chimpanzees (mostly males) who lived in four groups at Kyoto University’s Kumamoto Sanctuary. Researchers collected more than 600 hours of video footage of endangered primates and determined when and where each animal peed. I was there at the time. “I was a little overwhelmed because I didn’t know if I would get any meaningful results or if my efforts would be wasted,” says Onishi. “There were definitely times when I was nervous!”

“What may seem like a silly subject at first glance is actually quite fundamental.” —Matthew Campbell, Psychologist

By comparing their observations with computer simulations of randomized peeing, Onishi et al. found that, indeed, chimpanzees were more likely to urinate within 60 seconds of each other than if they acted randomly. Distance was also important. Animals within just a few feet of the first chimpanzee were much more likely to follow than those more than 10 feet away.

But perhaps the most interesting analysis came when Onishi and his colleagues looked at the social relationships among peeing chimpanzees. They were surprised to find that chimpanzees who were friends with the first animal to urinate were less likely to follow suit. But the chimpanzees who left first were less dominant. It was You become even more vulnerable to contagious pee.

“I initially expected that if a social influence existed, it might be similar to what we see with yawning; for example, stronger contagion between socially close pairs. and so on,” says Onishi. “Instead, we observed a clear effect of social status, with lower status people being more likely to defer to others’ urination.”

The new paper is only the first report, so more research is needed to understand this phenomenon and what insights it provides into the lives of chimpanzees. Scientists could perform similar analyzes on wild animals, for example, and Onishi expects the results would likely be consistent. Campbell also suggested that the apparently synchronized peeing led by the dominant chimpanzee may simply reflect the group’s daily routine, in which locomotion is coordinated by the dominant animal, which may take potty breaks before a road trip. I am also wondering if there is a possibility of encouraging this.

Co-author of the study, Shinya Yamamoto, a professor at Kyoto University, said this discovery allows us to think about chimpanzees a little differently. “This reinforces the impression that chimpanzees are social animals,” he says. “This study shows that even their physiological aspects are influenced by their social context.”

Professor Campbell said that depending on how precisely behavior is transmitted between animals, this discovery could shed light on how chimpanzees understand their bodies and whether they have a concept of urination. He points out that it may also be useful. “How this works and what it means for the chimpanzee’s mental life is the really interesting part for me,” he says. “It may seem like a silly topic at first glance, but it’s actually quite fundamental.”