A group of Japanese researchers discovered that the urination behavior of chimpanzees follows a social pattern similar to human yawning, as they urinate through social contagion suggesting that it could strengthen bonds within the group.
Just like yawning in humans, urinating seems to be a “contagious” behavior among chimpanzees. When one of them urinates, it is likely that others will do the same, which could serve to strengthen social bonds within the group. This is the main conclusion of a study published in Current Biology of Cell Press, conducted by scientists from the University of Kyoto (Japan). The research was carried out with twenty captive chimpanzees at the Kumamoto Sanctuary (Japan).
“In humans, urinating in company can be considered a social phenomenon. In fact, in Italy there is a proverb that says ‘who does not urinate in company, is either a thief or a spy’,” said Ena Onishi, a researcher at the University of Kyoto and lead author of the study. “In Japan, this act is known as ‘Tsureshon’ (連れション), and has been depicted in art throughout history, even appearing in modern social contexts,” adds Onishi.
“What our research suggests is that this behavior has deep evolutionary roots. We discovered that chimpanzees, our closest relatives, tend to urinate after others do so near them,” explained the researcher.
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## A study on synchronized urination in chimpanzees
The researchers noticed that the chimpanzees in the sanctuary tended to urinate synchronously, reminding them of human behavior and leading them to wonder if this phenomenon could be comparable to contagious yawning. Over more than six hundred hours of observation, they recorded 1,328 urinations by the chimpanzees, and analyzed the data to assess if they urinated synchronously and if their decision was influenced by the proximity of other chimpanzees or social factors.
The results showed that urinations were more synchronized than would be expected if the chimpanzees urinated at random. Additionally, the probability of a chimpanzee urinating increased when it was close to another who had already done so. The researchers also observed that chimpanzees of lower social rank in the hierarchy were more likely to urinate after seeing others do so.
## Social hierarchy and urination behavior in chimpanzees
The researcher commented that they were surprised that this contagion pattern was influenced by social rank, and that its influence was greater among lower-ranking chimpanzees.
Shinya Yamamoto, co-author of the study, pointed out that these results open up new interpretations about the social behavior of chimpanzees. “This phenomenon could reflect a type of hidden leadership to synchronize group activities, or even a reinforcement of social bonds among lower-ranking individuals,” Yamamoto suggests. This finding raises new questions about the social functions of urination in chimpanzees, suggesting that such an everyday behavior as urinating could play an important role in the cohesion and strengthening of bonds within their group.
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## Other curious behaviors of chimpanzees
Chimpanzees have curious behaviors that reflect their intelligence, socialization ability, and adaptation to the environment:
– **Communication behaviors:** these animals express emotions such as joy, sadness, fear, and empathy. Additionally, they can stand upright, wave their arms, throw branches or stones when angry. Males also show dominance through attacking displays.
– **Socialization behaviors:** Chimpanzees enjoy water and playing in the rain, which strengthens their bonds. They are also territorial and defend their space by forming patrol groups. When they feel threatened, these animals come together and forget their internal issues.
– **Tool-making behaviors:** This species is capable of making tools, not to mention that they are good at [breaking nuts](https://noticiasambientales.com/ciencia/chimpances-asombran-a-biologos-con-su-habilidad-para-romper-nueces). They are also known for building their nests, which are made of intertwined branches and leaves, providing comfort and insulation.
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