For Chimpanzees, Peeing is Contagious

Researchers Say Urination in Chimpanzees Reflects the Dynamics of Social Hierarchy

Even if you’re in top form, you’re likely to start yawning if you see someone else doing it. It’s a natural, almost instinctive reflex in humans.

The Contagious Urination Phenomenon

But in chimpanzees, our closest cousins, it’s not yawning that spreads… but the need to urinate, as a recent Japanese study reveals.

Published in the journal Current Biology, this study looks at a surprising phenomenon that a research team from Kyoto University has named “contagious urination.”

Study Findings

For over 600 hours, the researchers observed 20 chimpanzees in captivity at the Kumamoto sanctuary in Japan. The result: out of 1,328 documented urination episodes, they found a striking tendency towards synchronization, influenced by physical proximity and social interaction.

It appears that when a chimpanzee starts to urinate, its fellow chimpanzees quickly follow suit – a phenomenon closely linked to their physical proximity.

What’s even more astonishing is that it’s the least dominant individuals who imitate this behaviour first.

The researchers see this as evidence that urination in chimpanzees reflects the dynamics of social hierarchy, spreading progressively through the dominance structure.

A Social Phenomenon?

For chimpanzees, urinating is not simply a matter of physiology: it’s an act that subtly blends biology and social dynamics. This seemingly banal need to urinate can conceal unsuspected social issues in our closest cousins.

“For instance, [urination] could reflect hidden leadership in synchronizing group activities, the reinforcement of social bonds, or attention bias among lower-ranking individuals. These findings raise intriguing questions about the social functions of this behaviour,” explains study co-author, Shinya Yamamoto.

Implications and Future Research

The findings of this study are more than a scientific curiosity. They underline the potential role of this behaviour in chimpanzee group cohesion and social organisation.

This phenomenon could even shed light on certain aspects of human interaction. For, as Ena Onishi points out, urinating together can also be considered a social phenomenon in humans.

The scientists now hope to extend their research to other species to determine whether this “contagious urination” is specific to chimpanzees or representative of a more universal behaviour in the animal kingdom.

Conclusion

The findings go to show that, when it comes to animals, every detail can have a much deeper meaning than it might seem.

FAQs

Q: Why do chimpanzees urinate in sync with each other?

A: The researchers believe that urination in chimpanzees reflects the dynamics of social hierarchy, spreading progressively through the dominance structure.

Q: Is this phenomenon specific to chimpanzees?

A: The study suggests that it may be universal in the animal kingdom, but further research is needed to confirm this.

Q: Can this phenomenon be observed in humans?

A: Yes, researchers believe that urinating together can also be considered a social phenomenon in humans.