Some wild animals eat nectar or fruit containing naturally produced ethanol, but eating fermented food does not by itself prove that an animal gets drunk. A field study in West Malaysia documented seven mammal visitors to fermenting bertam palm nectar; researchers reported no visible signs of intoxication. A 2025 report separately documented wild chimpanzees sharing naturally fermented fruit with confirmed ethanol. Here is what the evidence shows about each animal—and what it does not show.
What counts as evidence that an animal eats fermented food?
Yeasts can produce ethanol as nectar or fruit ferments. To assess claims about “drunk” animals, it helps to separate three questions: Was the food shown to contain ethanol? Was the species or an individual animal documented consuming it? Were signs of intoxication observed or otherwise demonstrated? The examples below answer those questions with different levels of specificity; they are not a ranking of animals’ alcohol tolerance.
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Seven mammal visitors to bertam palm nectar
A 2008 field study at a West Malaysian rainforest documented seven mammal species visiting bertam palm inflorescences. The palm’s enclosed flower buds support yeast fermentation, and the nectar is consumed in a plant-pollinator relationship. Weier and colleagues measured alcohol concentrations averaging 0.6%, with a maximum of 3.8% in the nectar—not in the animals’ blood. They reported that flower-visiting mammals showed no signs of intoxication. Read the 2008 study and its supplementary material.
1. Pen-tailed treeshrew (Ptilocercus lowii)
Pen-tailed treeshrews frequently consume bertam palm nectar. The nectar measurements establish that their food can contain alcohol; they do not establish how much ethanol any individual ingests or absorbs. The study reported no visible signs of intoxication among the flower visitors.
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2. Common treeshrew (Tupaia glis)
Common treeshrews visited the inflorescences regularly during daytime, dusk, and dawn. Sampled common treeshrews were among the species the researchers identified as likely to ingest alcohol-containing nectar. That supports likely intake, not a finding that the animals became intoxicated.
3. Plantain squirrel (Callosciurus notatus)
Plantain squirrels were regular daytime visitors. A sampled female was among the animals identified as likely to have ingested food containing alcohol; the evidence does not demonstrate intoxication.
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4. Gray tree rat (Lenothrix canus)
Gray tree rats visited at night. A sampled male was identified as a likely consumer of alcoholic nectar, but no visible intoxication was reported.
5. Malayan wood rat (Rattus tiomanicus)
The study recorded Malayan wood rats as nocturnal visitors to the inflorescences. The available account does not separately establish alcohol intake by a sampled individual, so visiting should not be treated as proof of individually verified consumption.
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Chestnut rats were also recorded as nocturnal visitors. As with the Malayan wood rat, the reported visit is distinct from evidence that a particular sampled animal ingested ethanol-containing nectar.
7. Slow loris (Nycticebus coucang)
Slow lorises visited the nectar at night, and reviews describe them as consuming fermenting bertam palm nectar. Neither that description nor nectar consumption establishes that lorises visibly became drunk. A review of slow loris biology discusses the nectar case.
8. Western chimpanzees share naturally fermented fruit
A 2025 report from Cantanhez National Park in Guinea-Bissau documents wild western chimpanzees (Pan troglodytes verus) repeatedly ingesting and sharing naturally fermented African breadfruit containing confirmed ethanol. This is a separate fruit example, not part of the bertam palm study. The report documents fermented-fruit consumption and sharing; it should not be enlarged into a claim that the chimpanzees were drunk. Read the 2025 report.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Do elephants get drunk from marula fruit?
Elephants eat marula fruit, but the popular claim that they ordinarily become drunk from fallen fruit is not established by the cited evidence. A 2006 assessment found that even models biased toward inebriation did not show that elephants can ordinarily become drunk from marula. A 2023 yeast study likewise described the story as persistent and said empirical evidence that naturally fermenting marula fruit inebriates wild elephants remains elusive. The 2006 assessment and the 2023 study address the claim.
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What the evidence does—and does not—show
- Food containing ethanol: Bertam palm nectar was measured at 0.6% alcohol on average and up to 3.8% in the 2008 study. These are nectar concentrations, not measurements of intoxication in an animal.
- Documented consumption: The field study documented seven mammal species visiting the palm. Its sampled-animal evidence for likely intake was more specific for some visitors than others; a visit alone does not verify an individual’s ingestion.
- Observed intoxication: The authors of “Chronic intake of fermented floral nectar by wild treeshrews” (2008) stated: “Yet, the flower-visiting mammals showed no signs of intoxication.” That finding concerns visible signs in the observed visitors; it does not establish that every possible effect of ethanol was measured.
- Chimpanzees: The 2025 report supports repeated ingestion and sharing of fermented fruit containing confirmed ethanol, but the facts summarized here do not establish intoxication.
So, yes: animals consume foods that ferment naturally and contain ethanol. The documented examples here do not support calling all of them drunk, and the marula story does not establish ordinary intoxication in elephants.
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