Madrid, April 22, 2025 (Lusa) - A research team led by the University of Exeter set up cameras in Guinea-Bissau's Cantanhez National Park and filmed chimpanzees eating and sharing fermented African breadfruit, which contains ethanol (alcohol).
The fact that wild chimpanzees have for the first time been observed eating and sharing fruit mixed with alcohol is raising questions that scientists find fascinating, about whether and why these primates deliberately seek out alcohol.
The findings were published in Current Biology, Europa Press reported on Monday.
Humans have been believed to consume alcohol since ancient times, with benefits for social bonds. The new study suggests that humans' closest relatives may be doing something similar.
"In humans, we know that drinking alcohol triggers a release of dopamine and endorphins, which produce feelings of happiness and relaxation," Anna Bowland, from the Centre for Ecology and Conservation at Exeter's Penryn Campus, said in a statement.
"We also know that sharing alcoholic drinks, even through traditions such as feasts, helps to form and strengthen social bonds. Now that we know that wild chimpanzees eat and share ethanol-contaminated fruit, the question is: could they be getting similar benefits?" she asked.
The researchers used motion-activated cameras to film chimpanzees sharing fermented fruit on 10 different occasions.
The alcohol content of the fruit shared by these chimps was analysed. The highest level found was the equivalent of 0.61% ABV (alcohol content, a measure used in alcoholic drinks).
This is a relatively low figure. However, the researchers point out that this could be just the tip of the iceberg, since between 60% and 85% of the chimpanzees' diet consists of fruit, so low levels of alcohol in various foods could represent significant consumption.
The researchers emphasise that it is unlikely that chimpanzees would become intoxicated, as this would clearly not improve their chances of survival.
The impact of alcohol on chimpanzee metabolism is unknown. However, recent discoveries of a molecular adaptation that significantly increased ethanol metabolism in the common ancestor of African apes suggest that the consumption of fermented fruits may have ancient origins in species such as humans and chimpanzees.
"Chimpanzees don't share food all the time, so this behaviour with fermented fruit may be important," stressed Kimberley Hockings, also from the University of Exeter.
"We need to learn more about whether they deliberately seek out ethanol-contaminated fruits and how they metabolise them, but this behaviour could be one of the earliest evolutionary stages of ‘feasting’. If so, this suggests that the human tradition of feasting may have origins deep in our evolutionary history," the researcher emphasized.
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