Humans aren’t the only species that dabble in the occasional drink. From fruit flies to elephants, creatures across the animal kingdom have been observed consuming fermented foods. But what happens when our closest relatives show a taste for alcohol?

Wild chimpanzees, just about as close to humans as apes get on the genetic family tree, have been captured on film eating and sharing fermented fruit, which naturally contains alcohol. The footage, taken by a research team led by the University of Exeter in Guinea-Bissau’s Cantanhez National Park, shows a behavior that may offer valuable clues about the origins of human alcohol consumption and the evolution of social bonding.

Chimpanzees Sharing Food and Booze

Motion-activated cameras revealed chimpanzees gathering around African breadfruit trees, eating and sharing the fruit with one another as though engaged in a primordial happy hour. Later testing confirmed that the fruits contained ethanol — the same type of alcohol found in beer and wine — with levels as high as 0.61 percent ABV (alcohol by volume).

Although relatively low by the standards of an imbibing human, these amounts could accumulate over time, especially since 60 percent to 85 percent of a chimpanzee’s diet consists of fruit. As intoxication would be counterproductive for survival in the wild (and isn’t so great for longevity even in the average human society), the footage raises intriguing questions. Are these animals simply eating ripe fruit, or are they deliberately chasing a buzz by selecting the more fermented ones?

Before you answer that, it’s worth noting that, in the chimp footage, unshared fruit appeared less fermented (based on its appearance). And in 90 percent of the instances where food was shared, that fruit contained ethanol, suggesting the chimps might be picking up on visual cues to choose and share the boozy bites.

Read More: Drunken Monkey Hypothesis: Was Booze an Advantage For Our Ancestors?

Sharing in Chimpanzee Society

Food sharing is already known to play a key role in chimpanzee society, much like grooming. But the discovery that chimpanzees may also be sharing fermented foods introduces the idea that alcohol could have a role in reinforcing social bonds.

“For humans, we know that drinking alcohol leads to a release of dopamine and endorphins, and resulting feelings of happiness and relaxation,” said Anna Bowland from Exeter’s Centre for Ecology and Conservation in a press release. “So — now we know that wild chimpanzees are eating and sharing ethanolic fruits — the question is: could they be getting similar benefits?”

Whether or not the chimps experience the same neurochemical effects as humans, the act of sharing fermented fruit may provide a new perspective on the evolutionary role of food — and potentially alcohol — in social interactions. Fermented foods may also offer added nutritional value, such as increased vitamin content, making them high-value items worth sharing, according to the study published in Current Biology covering the observations.

The Roots of Feasting

The idea that alcohol consumption has deep evolutionary roots is supported by genetics. A molecular adaptation in an alcohol-processing enzyme (alcohol dehydrogenase) found in the common ancestor of African apes — including humans and chimpanzees — suggests that consuming fermented fruit is not new. Humans are believed to have started producing alcoholic beverages as early as 7,000 B.C.E. in what is now China, but our actual relationship with alcohol may stretch back millions of years, to a time before humans were humans.

“Chimps don’t share food all the time, so this behavior with fermented fruit might be important,” said Dr. Kimberley Hockings of the University of Exeter in the release. “We need to find out more about whether they deliberately seek out ethanolic fruits and how they metabolize it, but this behavior could be the early evolutionary stages of ‘feasting.’”

In humans, social eating and drinking often go hand in hand — especially during feasts and celebrations. If chimpanzees are engaging in similar behaviors, even at a rudimentary level, it suggests the roots of communal feasting could extend far beyond human culture.

To explore these questions further, many happy hours of long-term research are needed — tracking individual chimpanzees’ relationships, behavior, and food choices. While the current findings can’t confirm whether chimps consume ethanol intentionally, they add a rich layer to our understanding of how something as seemingly human as sharing a drink may have deep evolutionary origins.

Read More: Do Humans Truly Like the Taste of Alcohol: What Do Biologists Say?

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Having worked as a biomedical research assistant in labs across three countries, Jenny excels at translating complex scientific concepts – ranging from medical breakthroughs and pharmacological discoveries to the latest in nutrition – into engaging, accessible content. Her interests extend to topics such as human evolution, psychology, and quirky animal stories. When she’s not immersed in a popular science book, you’ll find her catching waves or cruising around Vancouver Island on her longboard.