These results confirmed the original hypothesis that chimpanzees tend to urinate synchronously rather than randomly. Further analysis showed that the closer a peeing chimpanzee was to another chimpanzee, the more likely that chimpanzee was to pee as well. This is evidence of social contagion. Finally, Onishi et al. They wanted to investigate whether social relationships (like socially close pairs evidenced by mutual grooming and similar behaviors) influence urinary transmission. The only social factor that was shown to be associated was dominance, with chimpanzees low in dominance being more likely to urinate contagiously.
There may still be other factors influencing behavior, and further experimental research on potential sensory cues and social triggers is needed to identify potential underlying mechanisms of the phenomenon. Additionally, this study was conducted in a captive chimpanzee population. Studies of wild chimpanzee populations are needed to better understand the potential evolutionary roots, and to explore possible links between contagious urination and factors such as range patterns and territory use. Certain connections need to be considered.
“This was an unexpected and interesting result because it opened up many different possibilities of interpretation.” Co-author Shinya Yamamoto said:also from Kyoto University. “For example, it may reflect covert leadership in synchronizing group activities, strengthening social bonds, or attentional biases between subordinate individuals. These findings suggest that the social function of this behavior It raises interesting questions about.”
DOI: Current Biology, 2025. 10.1016/j.cub.2024.11.052 (About DOI).
