There is numerous evidence of wild animals behaving as if they were “drunk” after eating fermented fruits, but despite this, it has been assumed that non-human consumption of ethanol is uncommon and accidental. However, scientists question this assumption in a study published in Trends in Ecology & Evolution.
The authors, led by Kimberley Hockings, argue that since Ethanol is naturally present in almost all ecosystems.it is likely that most animals that eat fruits and nectar consume it on a regular basis.
“We are moving away from this anthropocentric view that ethanol is simply something that humans use,” explains Hockings. Is much more abundant in the natural world than we previously thoughtand most animals that eat sugary fruits are going to be exposed to some level of alcohol.”
Ethanol first became abundant ago about 100 million years ago, when flowering plants began producing sugary nectar and fruits that yeast could ferment. Today, it is naturally present in almost all ecosystems, although concentrations are higher and production occurs year-round in lower latitude and humid tropical environments compared to temperate regions.
Most of the time, naturally fermented fruits only reach between 1 and 2% alcohol by volume (ABV), but they have been found concentrations of up to 10.2% ABV (similar to high-proof beers) in overripe palm fruits in Panama.
Animals had genes capable of breaking down ethanol before yeast began producing it, but there is evidence that Evolution fine-tuned this ability for mammals and birds that consume fruit and nectar.. In particular, primates and tree shrews have adapted to metabolize ethanol efficiently.
“From an ecological perspective, it is not advantageous to be drunk while climbing trees or surrounded by predators at night; That is a recipe for your genes not to be transmitted – adds Matthew Carrigan, co-author of the study -. It is the opposite of humans, who want to get drunk, but don’t really want the calories; From the non-human perspective, animals want the calories, but not the intoxication.”
It is not clear whether animals intentionally consume ethanol just for the sake of consuming it, and More research is needed to understand its impact on animal physiology and evolution.say the authors. However, they also explain that ethanol consumption could bring several benefits to wild animals.
Firstly, it is a source of calories, and the odorous compounds produced during fermentation could guide animals to food sourcesalthough the study suggests that it is unlikely that animals could detect ethanol on their own.
ethanol It could also have medicinal benefits: Fruit flies intentionally lay their eggs in substances containing ethanol, which protects their eggs from parasites, and fruit fly larvae increase their ethanol intake when parasitized by wasps.
“From a cognitive point of view, the idea has been proposed that ethanol can activate the endorphin and dopamine system, which produces a feeling of relaxation that could have benefits in terms of sociability – adds behavioral ecologist and co-author Anna Bowland -. To test this, we would really need to know if ethanol produces a physiological response in nature.”
There are many unanswered questions about the importance of ethanol consumption for wild animals. In their future research, Hockings’ team plans investigate the behavioral and social implications of ethanol consumption in primates and further examine the enzymes involved in alcohol metabolism.