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Tools to tipple: ethanol ingestion by wild chimpanzees using leaf-sponges

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Paper Summary

Paperzilla title
Chimps Get Their Buzz On, Thanks to Human Brewmasters!

This 17-year observational study found that wild chimpanzees frequently consume fermented palm sap, provided by human tapping, that contains up to 6.9% alcohol using leaf-sponges. The findings suggest that ethanol doesn't deter these apes and contribute to understanding the evolutionary history of ethanol consumption in primates, including humans.

Explain Like I'm Five

Wild chimpanzees learned to use leaf-sponges to drink alcoholic palm sap from containers that people left out, showing they don't mind a little booze and it might link to our own ancient ancestors.

Possible Conflicts of Interest

None identified

Identified Limitations

Human-Influenced Behavior
Chimpanzees are ingesting ethanol from palm sap made available by human tapping and collection methods, not purely natural sources, which limits the conclusions about natural selection pressures for ethanol consumption.
Limited Behavioral Data on Inebriation
While some chimpanzees reportedly showed 'behavioral signs of inebriation,' detailed before-and-after behavioral data were rarely collected, making it difficult to fully assess the effects of ethanol consumption.
Single Community Study
The observations are restricted to a single chimpanzee community, limiting the generalizability of these findings to other chimpanzee populations or other African ape species.
Inferential Human Relevance
The paper draws conclusions about the 'last common ancestor' of African apes and humans based on observations of chimpanzees, which is an inference and not a direct study of human behavior or evolution.

Rating Explanation

This is a valuable long-term observational study in primatology, providing novel quantitative data on tool use and ethanol ingestion in wild chimpanzees. However, the ethanol source is anthropogenic (human-tapped palms), which complicates its direct implications for natural evolutionary pressures. Furthermore, the paper's inferential links to human evolution, based on an animal study, limit its rating per the specified guidelines. Detailed behavioral data on inebriation were also lacking.

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File Information

Original Title: Tools to tipple: ethanol ingestion by wild chimpanzees using leaf-sponges
Uploaded: September 28, 2025 at 01:25 AM
Privacy: Public