It’s not uncommon to hear stories about drunk animals wreaking havoc on communities while intoxicated. From monkeys and raccoons to opossums and skunks, critters of all types have wound up drunk after breaking into garbage cans and even liquor stores in search of their fix. While these metropolitan incidents tend to dominate the conversation, scientists now have reason to believe that, in the wild, animals getting drunk is actually fairly common practice.
According to a study published on Wednesday in the journal “Trends in Ecology & Evolution,” ethanol (a compound produced from fermenting fruit and grain sugars) is present in almost every existing natural environment, making it likely that most fruit-eating or nectar-drinking animals are regularly consuming alcohol while feeding themselves. The research team — which included academics Anna Bowland, Amanda Melin, David Hosken, Kimberly Hockings, and Matthew Carrigan — also points out that flower and fruit-bearing plants arose over 100 million years ago, so the concept of wild animals eating alcoholic fruit isn’t necessarily a new one.
The authors explain that as these fruits age, fall off their trees or bushes, and begin to rot, wild yeasts in the air convert the fruit’s sugar to ethanol. Typically, these fruits only contain about 1 to 2 percent alcohol by volume (ABV), though the study’s researchers did discover some rotting palm fruits in Panama with ABVs over 10 percent. As fermenting fruits tend to have stronger scents than their non-fermenting counterparts, they’re also much easier for animals to find, allowing the team to infer that they are consumed more often than not.
“We’re moving away from this anthropocentric view that ethanol is just something that humans use,” Dr. Hockings, a behavior ecologist at the University of Exeter, explained in a statement. “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.”
While humans are largely attracted to alcohol for its intoxicating qualities, the study argues that animals are interested in these fruits for sustenance, not inebriation. Many fruit-eating species in the wild even have evolutionary genes that allow their systems to break down ethanol compounds faster to avoid getting drunk.
“It is not advantageous to be inebriated as you’re climbing around in the trees or surrounded by predators at night,” explained Carrigan, a professor of molecular ecology at the College of Central Florida. “That’s a recipe for not having your genes passed on.”
Still, it’s not a certainty that animals actually avoid getting drunk, and the idea remains a hypothesis. The study’s co-authors note that for some species of social animals, like birds and primates, booze consumption could even benefit their communities.
“On the cognitive side, ideas have been put forward that ethanol can trigger the endorphin and dopamine system, which leads to feelings of relaxation that could have benefits in terms of sociality,” explained first author Bowland, a behavior ecologist at the University of Exeter. “To test that, we’d really need to know if ethanol is producing a physiological response in the wild.”
More research is needed before scientists can establish how intoxication fully presents in wild animals compared to human beings. But in the meantime, we’re sure there will be plenty more drunk monkeys to observe.