The ability of wild animals to process alcohol in the wild

Researchers say that not only humans use alcoholic beverages, but even wild animals are 'tired' because alcohol is available in nature, originating from fermented fruits and nectar.

Alcohol occurs in nearly every ecosystem on Earth, causing most animals that feed on sweet fruits and nectar to regularly consume this intoxicating substance.

Many species have evolved to tolerate alcohol, and others have learned to protect themselves from it. Fruit flies, for example, lay their eggs in foods rich in ethanol, protecting them from parasites. There are also species that seem unable to handle the effects of alcohol in the wild.

A fruit fly. (Photo: Alamy).

After carefully studying research articles on animals and alcohol, a team of scientists at the University of Exeter (UK) found a "diverse group" of species that have consumed and adapted to ethanol from fermented fruits and nectar.

Ethanol has been common on Earth since about 100 million years ago, when flowering plants began producing sweet fruits and yeasts fermented nectar. Its natural alcohol content is usually low, around 1% to 2% alcohol by volume, but in overripe palm fruit, concentrations can be as high as 10%.

In one study, there was photographic evidence of wild chimpanzees in southeastern Guinea bingeing on raffia palm sap. Meanwhile, spider monkeys on Barro Colorado Island, Panama, preferred yellow mombin berries, which contained between 1% and 2.5% alcohol.

Wondering whether animals consuming alcohol in the wild get drunk is another matter. There are plenty of stories of drunk animals, from elephants and baboons getting drunk on marula in Botswana, to a moose getting its head stuck in a tree in Sweden after munching on fermented apples… But they haven't been tested for alcohol.

Animals that regularly eat fermented foods tend to metabolize alcohol quickly, avoiding its worst effects. But some animals that don't regularly consume ethanol may suffer the consequences.

Tests on dead Bombycilla cedrorum birds that crashed into fences and other structures showed they had flown under the influence of alcohol after eating overripe Brazilian pepper fruit.

Earlier this month, researchers at Tel Aviv University in Israel discovered that the oriental hornet may be the only animal capable of consuming unlimited amounts of alcohol without adverse behavioral effects or death.