A group of chimps have been filmed sharing alcoholic breadfruit, in the first example of wild primates having a booze-up on camera (well, sort of).
Researchers got hold of the fruit they were eating and tested it afterwards, and found the most alcoholic one they were gorging on was 0.61% strength.
It’s not quite vodka, but given that chimps mainly survive on fruit, at the levels they consume it’s possible they could get a buzz if they eat enough.
Researchers say that sharing food around like this is not typical chimp behaviour, so it is possible they did it because they liked the booze and were engaged in social bonding.
If true, it means that human behaviours passing a bottle or cigarette around a group could have deep roots in evolutionary biology.
The chimps were filmed enjoying themselves in the west African jungle in Guinea Bissau’s Cantanhez National Park.
Anna Bowland, from the University of Exeter, said: ‘For humans, we know that drinking alcohol leads to a release of dopamine and endorphins, and resulting feelings of happiness and relaxation.
‘We also know that sharing alcohol – including through traditions such as feasting – helps to form and strengthen social bonds.
‘So – now we know that wild chimpanzees are eating and sharing ethanolic fruits, the question is: could they be getting similar benefits?’
This wasn’t just a fluke. The motion-activated cameras they set up to film the chimps captured ten different occasions of the animals sharing boozy fruit.
Nine of ten of the sharing events were ‘passive’, when a fellow chimp tolerated a peer feeding from their fruit.
On one occasion, a chimp even let fruit be taken from its mouth.
While it’s entertaining to imagine chimps on the lash and falling asleep under trees, researchers said that they likely have better attitudes to booze than their human cousins.
Alcoholic fruit and flowers
The fruits the chimps were seen eating were relatively soft by nature’s standards: the equivalent of a Coors Light lager, rather than Jack Daniels.
Most of the time, naturally fermented fruits only reach 1-2% alcohol by volume (ABV).
However, concentrations as high as 10.3% have been found in over-ripe palm fruit in Panama, researchers said in a previous study last year.
Alcohol was being drunk long before humans got around to brewing it.
Flowering plants started producing sugary nectar containing ethanol around 100 million years ago, as well as fruits which could ferment.
Dr Kimberley Hockings, who was also involved in the study published today, said: ‘We’re moving away from this anthropocentric view that ethanol is just something that humans use..
‘It’s much more abundant in the natural world than we previously thought, and most animals that eat sugary fruits are going to be exposed to some level of ethanol.’
They are unlikely to get drunk on the fruit, as this would not give them any evolutionary advantage, and would actually damage their survival chances (not least the fact it would be difficult to get hammered on something that is 0.6% ABV).
It is possible they could share the alcoholic fruit due to its higher vitamin content, rather than its inebriating effects, though more research is needed.
Scientists don’t know the exact effect of alcohol on chimps’ metabolism, although there have been other recent studies into animal booze consumption.
A molecular adaptation that greatly increased ethanol metabolism in the common ancestor of African apes was recently discovered./
It suggests eating fermented fruits may have ancient origins in species including humans and chimps.
Dr Kimberley Hockings, also from the University of Exeter, said: ‘We need to find out more about whether they deliberately seek out ethanolic fruits and how they metabolise it, but this behaviour could be the early evolutionary stages of “feasting”.
‘If so, it suggests the human tradition of feasting may have its origins deep in our evolutionary history.’
So if you find yourself deep in a bender with mates this weekend, you can call it field research into our shared genetic and social pathways. Maybe.
– The paper, Wild Chimpanzees Share Fermented Fruits, is published in the journal Current Biology.
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