Drinking alcohol is not just a human thing. Animals have unknowingly been taking a sip of alcohol for centuries, sipping it from fruits and grains containing ethanol, a form of alcohol produced by the fermentation of sugars. Published in Trends in Ecology & Evolution, the study revealed that animals worldwide regularly experience alcohol through their diet.

How do animals end up ingesting alcohol?

Ethanol is generated in rotting fruits as yeasts ferment sugars on the surface of the fruit from the air. Such fruits, smelling like beer or wine, can have 1-2 percent alcohol by volume (ABV), similar to low-alcohol beers or kombucha. The ABV, however, can be far higher: decaying palm fruits in Panama have measured over 10 percent ABV, similar to wine.

According to the study, observed by the University of Exeter behavioral ecologist and senior author Kimberley Hockings, “Ethanol is not just something that humans use." 

Alcohol-producing fruits have existed as far back as nearly 100 million years ago, that is way back in the late Cretaceous period. Therefore, ethanol-bearing plants existed when the Tyrannosaurus rex, dinosaurs, dominated Earth.

Though intoxication might be the reason man searches for alcohol, animals are not that clever. Even a very minimal amount of alcohol makes them unstable, which may land them in some hazardous situations.

"It is not advantageous to be inebriated as you’re climbing around in the trees or surrounded by predators at night—that’s a recipe for not having your genes passed on,” noted coauthor Matthew Carrigan, a molecular ecologist at the College of Central Florida.

While humans often drink to get intoxicated without necessarily needing the calories, it’s quite the opposite for animals. "Animals want the calories but not the inebriation," he explained. Over time, many animals have even evolved genes that help them break down ethanol quickly, allowing them to gain the benefits of these calorie-dense fruits without the downsides of inebriation.

Do animals really drink alcohol?

Even though the research indicates that animals do not try to become intoxicated, it still suggests that they may consume it unknowingly or even desire the effect. Whether animals are attracted to ethanol for its effects or simply consume it incidentally remains uncertain.

This breaks away from this old, ancient assumption of ethanol consumption being a solely human affair, instead showcasing a much more ancient interaction between animals and alcohol in the natural world.