The act of gathering to enjoy food and beverages is often considered a distinctly human trait. However, recent observations of wild chimpanzees suggest that this social activity may extend beyond humans. Researchers have documented these primates sharing fermented African breadfruit, which contains notable levels of alcohol. This finding, featured in a study published in Current Biology, marks the first time the sharing of alcoholic foods among nonhuman great apes has been observed in their natural habitat.
The seasonal fruit, derived from trees known as Treculia africana, is abundant in Cantanhez National Park in Guinea-Bissau, where the chimps reside. Once fully ripened, the fruits fall to the ground and transition from a hard, green exterior to a softer, yellow texture. Given that the chimpanzees are unhabituated to human presence, researchers set up camera traps at three different locations to capture their feeding and sharing behaviors.
The team recorded 10 instances of selective sharing among a group of 17 chimpanzees, revealing a clear preference for riper fruits. During the months of April to July in 2022, the researchers used a portable breathalyzer to measure the alcohol content in the fallen fruit. Their findings indicated that nearly 90 percent of the ripe fruit contained ethanol, with the highest concentrations measuring an equivalent of 0.61 percent alcohol by volume (ABV).
Although this level of alcohol is relatively low compared to typical human beverages, fruit represents a significant portion of the chimpanzees’ diet, accounting for 60 to 80 percent of what they consume daily. Consequently, the cumulative amount of ethanol they might ingest could be considerable. Nevertheless, the chances of these chimps becoming intoxicated are slim. The research suggests that such an outcome would not offer any evolutionary benefit, and there is evidence pointing to an evolutionary trait in the common ancestor of African apes that enhances their ability to metabolize alcohol.
