Chimps Get Their Buzz On: Scientists Uncover Wild Primates' Surprising Alcohol Habit

For decades, the notion of regular alcohol consumption has been largely confined to human society, with our complex relationship with fermented beverages shaping cultures and economies alike. However, a fascinating and groundbreaking study has turned this assumption on its head, revealing that our closest primate relatives, wild chimpanzees, are no strangers to a daily tipple.

In the lush forests of Bossou, Guinea, a community of wild chimpanzees has been under scientific observation for over three decades.

These highly intelligent primates have developed a unique cultural tradition: they skillfully tap the sap from raffia palm trees, then use carefully crafted "leaf sponges" to soak up and consume the fermented liquid. It's a behavior that has intrigued researchers, but the extent of their alcohol intake remained largely unquantified until now.

Published in Royal Society Open Science, a new study meticulously documented the drinking habits of these Bossou chimps.

Researchers, led by scientists from Oxford Brookes University and Kyoto University, analyzed 17 years' worth of video footage, observing 20 individual chimpanzees as they indulged in their palm sap routine. What they discovered was astonishing: some chimpanzees were regularly consuming significant quantities of naturally fermented palm sap, which can have an alcohol content of up to 3 percent.

The calculations are eye-opening.

On average, the chimpanzees consumed enough sap to equate to a daily intake of 1.7 to 2.4 units of pure alcohol, comparable to nearly two standard alcoholic drinks for a human. For a primate of their size, this is a considerable amount. While not all individuals consumed alcohol, and intake varied daily, the fact that some chimps were regularly imbibing such quantities challenges the long-held belief that humans are unique in their capacity for routine alcohol consumption.

The study also provided insights into the chimpanzees' behavior post-consumption.

While researchers noted no overt signs of extreme intoxication or loss of motor control, some individuals were observed to be calmer, more relaxed, or even drowsy after a significant drinking session. These subtle behavioral changes suggest that the alcohol was indeed having an effect, albeit not always to the point of incapacitation.

This research lends significant weight to the "drunken monkey hypothesis," which posits that our primate ancestors may have been drawn to the scent of fermented fruit as a cue for ripe, energy-rich food.

Over evolutionary time, a tolerance, and perhaps even a preference, for ethanol could have developed. The Bossou chimps offer a living example of how non-human primates can and do consume alcohol, and how their bodies process it.

The implications of this study are profound. It suggests that the capacity to metabolize alcohol, and even to enjoy its effects, might have a much deeper evolutionary history than previously thought, predating the divergence of humans and chimpanzees.

Furthermore, it opens new avenues for understanding human alcohol preferences and our genetic predispositions to consume it, rooted perhaps in a shared primate past. The next time you enjoy a drink, consider that your chimpanzee cousins might be raising a leaf-sponge toast right along with you.