Wild chimpanzees in Uganda and Ivory Coast are getting a daily dose of alcohol from fermented fruit, researchers have found. Measurements of ethanol in fallen fruit in Kibale and Taï national parks suggest that chimps consume about 14g of pure ethanol per day—roughly the equivalent of one standard US drink or half a pint of 5% ABV beer.
Individual fruits contained less than 0.5% alcohol, but the apes eat 5–10% of their body weight in ripe fruit daily, with figs among their favorites. Despite consuming around 4.5kg of fruit each day, the chimps show no obvious signs of intoxication.
The findings support the “drunken monkey” hypothesis, which suggests that humans’ attraction to alcohol may have roots in primates’ ancestral need for energy-rich, fermented fruit. Previous studies have also documented habitual alcohol consumption in other chimp troops and animals, including slow lorises.
While chimps tolerate this natural intake, humans are advised to limit alcohol to 14 units per week, although research indicates there is no completely safe level of consumption.
