Q: Do animals drink alcohol?

Krishna:

In nature, plants don’t produce ethanol directly. Instead, it’s made primarily by the yeast Saccharomyces cerevisiae as it ferments sugars. Evidence suggests that yeast began making ethanol 100 million years ago, when flowering plants first started producing sugar-rich fruits. Today, ethanol-laden fruits can be detected in nearly every terrestrial ecosystem.

Concentrations of ethanol in naturally fermented fruits can be as low as 1-2% alcohol by volume (ABV), and as high as 10.2% ABV in some overripe palm fruits. (7)

Growing evidence shows that many types of animals consume alcohol or some other intoxicants in nature, from tiny flies, wasps and bees to monkeys, some birds, chimpanzees and elephants, the researchers found. Moreover, their review showed that animals had the genes to metabolize ethanol long before yeasts even began producing it.

Several non-human animal species are said to engage in apparent recreational drug use too, that is, the intentional ingestion of psychoactive substances in their environment for pleasure, though claims of such behaviour in the wild are often controversial. This is distinct from zoopharmacognosy, in which animals ingest or topically apply non-food substances for their health benefits, as a form of self-medication. (1)

However, many animals seem to consume alcohol but likely not for the same reason that humans do. Alcohol metabolism may have evolved as a survival advantage in the wild.

In 2007, Anchorage Daily News reported a goofy looking moose tangled up in Christmas lights. A local biologist guessed that the animal had eaten too many fermented crab apples from a nearby tree and may have been drunk from the alcohol in the fruit. The idea of drunk animals is simultaneously absurd and amusing—it's not surprising that Buzzwinkle the drunk moose and his friends made the headlines.

Ethanol commonly occurs in nature, and a lot of animals in the wild, especially those whose diets consist of fruits and nectar, consume it at least occasionally (2).

However, it’s disadvantageous—even dangerous—for animals to roam around while under the influence. For this reason, animals likely evolved the ability to metabolize alcohol so they wouldn’t get intoxicated. 

One of the best documented examples of wild animals consuming alcohol is the story of the West Malaysian pentailed tree shrews. In a 2008 study in the Proceedings of the National Academy of Sciences, researchers observed tree shrews slurping on alcoholic palm nectar in the middle of the night (3).

The researchers reported that the tree shrews’ diet mostly consisted of this alcoholic nectar. They estimated that if the tree shrews metabolized alcohol at the same rate as humans, the animals would be intoxicated for approximately a third of their lives. Yet, the tree shrews showed no signs of intoxication, which suggests that they can metabolize alcohol very effectively and quickly.

Animals  usually eat alcoholic fruits that contain low quantities of the substance, instead of directly drinking like human beings. 

Common chimpanzees have been observed eating overripe breadfruit and sharing it with fellow members of their troop. Wild chimpanzees in Bossou, Guinea, have been observed consuming fermented sap from the raffia palm (Raphia hookeri) (1).   

Some vervet monkeys in the Caribbean, particularly teenaged individuals, exhibit a preference for alcoholic beverages over non-alcoholic ones, a taste which likely developed due to the availability of fermented sugar cane juice from local plantations.

Some monkeys often raid bars and tourist beaches for alcoholic drinks, and become visibly inebriated.

Cedar waxwing, bohemian waxwing, common starling are frequently studied species when examining the effects of alcohol consumption in birds. Cedar waxwings have been observed flying while intoxicated by alcohol from overwintered hawthorn pommes ("haws"), resulting in crashes that lead to their deaths. (1)

Elephants seeking out the fermented fruit of the marula tree, and showing signs of intoxication, including increased aggression, after doing so has also been observed.

African Animals Getting Drunk From Ripe Marula Fruit

A 2010 study from the University of Haifa reported that bees prefer nectar containing nicotine and caffeine over that without, and suggested that this preference may be part of the reward system driving the mutualistic feeding behaviour. (4)

About 70% of domestic cats are attracted to, and affected by, the plant Nepeta cataria,  also known as catnip. The plant also affects some wild cats, including tigers, though the percentage of these cats affected is unknown. Cats sniff, lick, and sometimes chew the plant, and may rub against it, with their cheeks and whole body, by rolling over it. (1)

Researchers reported that a group of rough-toothed dolphins near the Azores were pushing around inflated puffer fish and behaving lethargically. Puffer fish defensively excrete tetrodotoxin, which might have been having an intoxicating effect on the dolphins . (5)

Black lemurs have been documented gently biting toxic millipedes, which causes them to salivate, and then rubbing their saliva and the millipede secretions on their fur. The millipede toxins, including cyanide and benzoquinone, are thought to act primarily as an insect repellent, protecting the lemurs from diseases such as malaria, thus making this behavior a form of zoopharmacognosy. However, the toxins also appear to have a narcotic effect on the lemurs, causing them to enter an apparently blissful state, which may serve as a reward for the behaviour. (1)

In Tasmania, wallabies have been reported repeatedly entering commercial poppy fields, consuming the plants, and showing signs of intoxication. (6)

Reindeers eat mushrooms to get intoxicated. Some sheep eat lichens to get the effect. Watch the video below to know how.

Based on existing research, ethanol could be beneficial in a number of ways for the animals, including as a source of calories and for its medicinal properties . For instance, fruit fly larvae consume more ethanol when they’re parasitized by wasps, suggesting they may be self-medicating. Fruit flies have also been reported to intentionally lay their eggs in substances containing ethanol to protect them from parasites.(7)

So  “ethanol is neither rare nor simply avoided” in nature. “This leads us to reconsider ethanol’s ecological role and evolutionary impact in nature,” researchers think.

Footnotes:

1. https://en.wikipedia.org/wiki/Recreational_drug_use_in_animals

2. Bowland AC, et al. The evolutionary ecology of ethanol. Trends Ecol Evol. 2025;40(1):67-79.

3. Wiens F, et al. Chronic intake of fermented floral nectar by wild treeshrews. Proc Natl Acad Sci U S A. 2008;105(30):10426-10431.

4.  Singaravelan, Natarajan; Nee'man, Gidi; Inbar, Moshe; Izhaki, Ido (2005). "Feeding Responses of Free-flying Honeybees to Secondary Compounds .... Journal of Chemical Ecology. 31 (12): 2791–2804.

5. Goldman, Jason G. (May 27, 2014). "Do animals like drugs and alcohol?". BBC Future. Archived from the original on March 24, 2023. Retrieved March 22, 2023.

6. "Stoned wallabies make crop circles". BBC World News. June 25, 2009. Archived from the original on March 22, 2023. Retrieved March 22, 2023.

7. https://news.mongabay.com/short-article/2024/11/animals-consume-alc...'s%20also%20growing%20evidence%20that,yeasts%20even%20began%20producing%20it.