From the rainforests of Africa to your local brewery, alcohol has shaped human cultures for millennia. But what if our thirst for booze started with our ancestors swinging from the trees? A new study in Science Advances suggests that wild chimpanzees regularly get tipsy on fermenting fruit — the equivalent of a pint of beer per day.
Researchers led by Aleksey Maro from the University of California, Berkeley, collected samples of ripe fruits that chimps naturally eat and measured their ethanol content. They found that, on average, chimps ingest about 14 grams of pure alcohol each day through these fruits.
"It’s not an insubstantial amount of alcohol, but very diluted and more associated with food," says Maro. Corrected for body size, this daily intake matches a human pint of beer.
This discovery breathes new life into the long-debated "drunken monkey theory," first proposed over a decade ago by biologist Robert Dudley. The idea: primates that could tolerate and even crave the low doses of alcohol in fermented fruit had an evolutionary edge.
"The drunken monkey hypothesis is becoming more and more a reality," Maro notes, although he prefers the name "evolutionary hangover."
Anthropologist Nathaniel Dominy from Dartmouth College, who was not involved in the research, calls the paper "a tour de force" that settles questions about ethanol in tropical fruits. Yet, he points out, many mysteries remain: Do chimps actively seek boozy fruits, or do they just eat whatever they find?
As scientists continue to study these behaviors, we may uncover more about our own relationship with alcohol — from biology to behavior — by observing our closest living relatives.
Reference(s):
Wild chimps eating fermenting fruit get a surprising slug of alcohol
cgtn.com
