It’s long been known that chimpanzees, our nearest primate relatives, are social creatures. The fact that they sometimes consume fermented fruit, with a small but discernible alcohol content, is also well documented. Yet never before had chimpanzees been filmed “sharing” boozy fruit in the wild, in a social ritual akin to humans going out and having a few drinks together.
The behavior was captured by University of Exeter researchers at Cantanhez National Park in the West African nation of Guinea-Bissau. In a recent publication, the scientists admit that they don’t yet understand why the chimps decided to share the fermented breadfruit, though they suggest that it might have something to do with social bonding and cohesion. Additionally, the fact that chimpanzees, like humans, have the enzymes required to metabolize alcohol could mean that our common ancestor developed this ability early in our evolutionary history. This would long predate the oldest known archaeological evidence of humans drinking alcoholic beverages, which dates to around 10,000 years ago.
Hidden cameras captured 10 separate occasions in which the chimpanzees consumed the fermented breadfruit together, though the researchers’ definition of “sharing” was very broad: in most cases, the chimpanzees simply allowed their companions to take the breadfruit from their grasp, rather than actively passing it from one individual to another.
The researchers contend that this behavior has probably been observed before, yet without anyone realizing it. The University of Exeter team calculated the alcohol-by-volume content of the breadfruit to be anywhere between 0.01% and 0.61%, which is notably modest by human standards. Although this is far lower than the alcohol in a beer or a glass of wine, when considering that a chimpanzee’s diet is predominantly fruit, the impact could be quite significant.
Pass the fermented breadfruit, please:
- Further research about the chimpanzees’ behavior after consuming boozy breadfruit could reveal whether its alcohol content is enough to make them drunk, and whether inebriation could be their goal.
- Surprisingly, chimpanzees have been observed sharing meat relatively frequently, but it’s much rarer for them to share fruit or plant matter.
- In 2015, researchers published evidence of adult chimpanzees near Bossou, Guinea, consuming alcohol from naturally fermented sap from raffia palm trees, with observations collected over 17 years. Compared to the very slightly alcoholic breadfruit, the raffia sap had a much higher alcohol content, estimated to be between 3.5% and 6.9% alcohol by volume. The chimpanzees, who always drank alone, displayed tell-tale signs of inebriation, including restlessness and falling asleep soon after drinking the palm wine.
