Chimpanzees drink the equivalent of two or three beers a day, study says

"A team of biologists from the University of California, Berkeley analyzed more than 500 fruit samples from 20 plant species in the forests of two national parks: Kibale (Uganda) and Tai (Ivory Coast). There, chimpanzees of two different subspeciesthe eastern (Pan troglodytes schweinfurthii) and the western (P. t. verus)eat about 4.5 kilograms of fruit per day, with an average ethanol content of 0.31% to 0.32%."

"The researchers argue that these data support the drunken monkey hypothesis, proposed more than two decades ago by Robert Dudley, co-author of this new research, according to which the human fascination with alcohol has an evolutionary origin. The natural fermentation of ripe fruit, the theory goes, exposed hominids to small doses of ethanol for millions of years. This exposure may have led to physiological adaptations, such as more efficient enzymes for metabolizing it, but also a behavioral bias."

Biologists analyzed over 500 fruit samples from 20 plant species in Kibale (Uganda) and Tai (Ivory Coast). Eastern and western chimpanzees consume roughly 4.5 kilograms of fruit per day with average ethanol concentrations of about 0.31–0.32%, yielding an intake of approximately 13–15 grams of alcohol daily. That intake is comparable, by body-weight equivalence, to two or three beers for a human. These results support the drunken monkey hypothesis that natural fermentation exposed hominids to ethanol for millions of years, potentially producing metabolic adaptations and a behavioral attraction to ethanol as an olfactory cue and feeding stimulant.

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