Chimpanzees regularly consume alcohol from fermented fruits, study reveals
Chimpanzees regularly eat fermented fruit in the wild, ingesting notable amounts of alcohol in the process, according to a new study published in Science.
Researchers led by Aleksey Maro from the University of California reported this month that the animals consume a daily dose equivalent to about one small bottle of beer for humans.
The team studied chimpanzees in Uganda’s Kibale National Park and the Ivory Coast’s Taï National Park, analysing the 20 most popular fruit varieties. They found that the ripe pulp contained an average alcohol content of 0.3 per cent.
Given that a chimpanzee eats around 4.5 kilograms of these fruits each day, the intake amounts to nearly 14 grams of alcohol.
When compared with the animals’ average body weight of 41 kilograms, this is equivalent to a human drinking more than half a litre of beer.
The findings suggest that regular alcohol consumption is not only a cultural phenomenon among humans but may also have deeper roots in the behaviour of our closest relatives.
These results mirror another study published earlier this year by a University of Exeter team, which observed chimpanzees consuming alcoholic fruits in groups at Cantanhez Forests National Park in Guinea-Bissau, West Africa.
Most of the African breadfruit tree fruits examined contained up to 0.61 per cent alcohol, though it was unclear whether such low concentrations caused intoxication.
Camera traps
Using camera traps, the researchers recorded 70 events in which chimpanzees almost always consumed the fruits together. Both males and females, across different age groups, took part.
“Our data provide the first evidence for ethanolic food sharing and feeding by wild nonhuman great apes, and supports the idea that the use of alcohol by humans is not ‘recent’ but rather rooted in our deep evolutionary history,” the team wrote in Current Biology in April.
For many years, scientists assumed wild animals consumed ethanol—the scientific name for alcohol—only rarely and by accident.
However, a study published in January 2025 in Trends in Ecology & Evolution showed that alcohol consumption is fairly common among wild monkeys, birds, and insects.
“It’s much more abundant in the natural world than we previously thought, and most animals that eat sugary fruits are going to be exposed to some level of ethanol,” said behavioural ecologist Kimberley Hockings from the University of Exeter, who also contributed to the earlier study. She added that the substance “can be found in nearly every ecosystem.”
