A new study has found that it’s not just people who like to get a buzz from alcohol.
Scientists discovered that monkeys, lemurs and birds also feast on fruits and nectar that contain ethanol – the main component of alcohol.
The fermented fruits typically contain up to two percent alcohol by volume (ABV), but the researchers explained that some, such as overripe palm fruits in Panama, had an alcohol content of 10.2 percent.
They observed that primates were among the largest groups to deliberately ingest ethanol to get a buzz, just like humans.
It has been documented that chimpanzees used leaf sponges to collect sap with noticeable ethanol concentrations and continued to consume it.
First author Anna Bowland from the University of Exeter said: ‘On the cognitive side, ideas have been put forward that ethanol may activate the endorphin and dopamine systems, leading to feelings of relaxation which may have benefits in terms of sociality.’
Ethanol is present in almost every ecosystem and is found in most fruits and nectar, which could explain why there are stories of wild animals acting ‘drunk’.
Senior author Kimberley Hockings said: ‘We’re moving away from this anthropocentric view that ethanol is just something people use.
‘It is much more common in the natural world than we previously thought, and most animals that eat sugary fruits will be exposed to some level of ethanol.’
Researchers from the University of Exeter in Britain focused on the eating habits of animals captured from the wild and found that many showed no aversion to the ethanol content.
In fact, when they looked at randomized food preference experiments, the team found that animals were more likely to choose the food option that contained a higher ethanol content.
A new study has uncovered several documented cases showing primates deliberately ingesting ethanol in a similar way as humans would. They use leaves to capture fermented nectar and ignore high concentrations of ethanol
Captive aye-ayes – also known as long-fingered lemurs – showed a preference for foods with higher ethanol concentrations ranging from two to five percent alcohol.
The number of documented cases of wild animals consuming fermented fruits and nectar is rare, but the new study published in the journal Trends in ecology and evolution found that this could only be due to a lack of research.
There have been claims of animals behaving strangely after ingesting food containing ethanol, including reports of mid-air accidents involving cedar waxwings that had ingested fermented berries.
However, the stories were often dismissed as unnatural, coincidental or unsubstantiated, leading scientists to believe that ethanol was limited to human ancestors.
These animals have adapted over time to metabolize ethanol effectively, the researchers noted, but added that it is still not clear whether they are consuming the ethanol intentionally.