The Drunken Monkey Theory: Why We Might Be Born to Like Alcohol
TECHNOLOGY & SCIENCE
10/8/2025
A1–A2 Level
Vocabulary
fruit (noun) — a sweet part of a plant that we eat.
Example: Bananas and apples are my favourite fruits.
alcohol (noun) — a drink such as beer or wine that can make people feel dizzy.
Example: Some adults drink alcohol at parties.
monkey (noun) — an animal that looks like a small person with a tail.
Example: The monkey climbed the tree to get fruit.
scientist (noun) — a person who studies science.
Example: The scientist looked at the animals carefully.
theory (noun) — an idea that explains something.
Example: The teacher explained a new theory about animals.
Article: The Drunken Monkey Theory
Scientists have found that chimpanzees — animals very similar to humans — sometimes eat fruit that has alcohol in it. The alcohol comes from a natural process called fermentation, when fruit gets old and starts to change.
In some places in Africa, like Uganda, chimps eat a lot of these fruits, especially figs. Even though each fruit has a small amount of alcohol, they eat so many that it adds up!
One study showed that chimps can drink as much alcohol as half a pint of beer every day just from eating fruit.
A scientist named Robert Dudley says this may explain why humans enjoy alcohol. He believes our ancestors also ate ripe fruits with alcohol long ago. This could mean that our taste for alcohol is very old and comes from nature.
Comprehension Questions
What kind of fruit do chimps like to eat?
Where does the alcohol in the fruit come from?
What is the name of the scientist who studied this?
Personal Questions (A1–A2)
Do you like fruit? What is your favourite one?
Have you ever seen a chimpanzee or monkey?
Do you think monkeys are smart?
What do you think chimps eat in the wild?
Have you visited a zoo before?
Do people in your country drink alcohol?
What drinks are popular in your country?
What do you think about the idea that humans and chimps are similar?
Do you like learning about animals?
What do you usually eat for energy?
Do you think alcohol is healthy or unhealthy?
Have you ever heard of fermentation before?
What fruits grow in your country?
Do you think chimps are funny or interesting?
Would you like to see a chimp in the wild?
Answer Key (A1–A2)
Figs and other ripe fruits.
From fermentation when fruit gets old.
Robert Dudley.
B1–B2 Level
Vocabulary
fermentation (noun) — a natural process that turns sugar into alcohol or gas.
Example: Fermentation makes bread rise and wine ferment.
ancestor (noun) — a person or animal from whom others come.
Example: Our ancestors lived thousands of years ago.
evolution (noun) — the process of change in living things over time.
Example: Evolution explains how humans developed from earlier animals.
consume (verb) — to eat or drink something.
Example: People should be careful about how much sugar they consume.
energy (noun) — power from food or drink that helps you move or think.
Example: Bananas give me energy before I go running.
Article: The Drunken Monkey Theory
Humans and chimpanzees share about 98% of the same DNA, and it turns out we might also share a taste for alcohol. Scientists studying wild chimps in Africa found that they often eat fruit that naturally contains small amounts of alcohol.
The alcohol comes from fermentation, a natural process that happens when fruit becomes very ripe. Although each fruit has less than 1% alcohol, chimps eat so much that they consume the same amount as half a pint of beer each day.
In a 2015 study, some chimps were also seen drinking palm sap with higher alcohol levels. Other animals, like slow lorises, have been shown to prefer foods with alcohol too.
Robert Dudley, a scientist at the University of California, believes this helps explain humans’ liking for alcohol. His “drunken monkey” theory suggests that our primate ancestors were drawn to ripe fruit because it provided energy — and sometimes a little alcohol. Over time, both chimps and humans may have developed a natural attraction to the smell and taste of fermented fruit.
This means our taste for alcohol may not only come from culture, but also from evolution itself.
Comprehension Questions
How much alcohol do chimps consume each day from fruit?
What does the “drunken monkey” theory say?
How could liking alcohol be connected to evolution?
Personal Questions (B1–B2)
Do you find this study surprising? Why or why not?
Do you think animals can enjoy food or drink like humans do?
What similarities do you see between people and primates?
What kind of fruit do you think animals like most?
Do you believe humans’ habits can come from evolution?
How do you think early humans found alcoholic drinks?
Do you think alcohol has any positive uses?
Are alcoholic drinks part of your country’s culture?
How do you think alcohol affects behaviour?
What do you think of scientists studying animal habits?
Have you ever seen an animal acting like a human?
Do you think this research helps us understand people better?
What kind of food or drink gives you energy?
Is it possible for natural habits to change over time?
Do you believe taste is more biological or cultural?
Answer Key (B1–B2)
About the same as half a pint of beer.
That humans and primates developed a taste for alcohol from eating ripe fruit.
It may be a result of our ancestors’ diet and natural selection.
C1–C2 Level
Vocabulary
ethanol (noun) — the type of alcohol found in drinks like beer and wine.
Example: Scientists measured how much ethanol the chimps consumed from fruit.
fermentation (noun) — the chemical process by which sugar changes into alcohol or acid.
Example: Fermentation in overripe fruit produces small amounts of alcohol naturally.
hypothesis (noun) — an idea or explanation based on limited evidence, used for research.
Example: The study tested the hypothesis that animals are drawn to fermented fruit.
adaptive (adjective) — helping something survive or adjust to its environment.
Example: Eating fermented fruit might have been an adaptive behaviour for early primates.
lineage (noun) — the line of family or species development over time.
Example: Humans share a long evolutionary lineage with chimpanzees.
Article: The Drunken Monkey Theory
According to recent research, our fondness for alcohol may have deep evolutionary roots. Studies on wild chimpanzees show that they frequently consume fermented fruit containing measurable levels of ethanol — up to the equivalent of half a pint of beer per day.
The alcohol is produced through natural fermentation, a process that occurs as fruit ripens and sugars are converted into alcohol. In Uganda and Ivory Coast, chimps were observed eating large amounts of these overripe fruits, particularly figs, which contain higher alcohol levels.
This behaviour supports the “drunken monkey” hypothesis proposed by biologist Robert Dudley. He argues that our primate ancestors regularly ate fermented fruits, which were rich in sugar and energy. Over generations, the preference for the scent and taste of ethanol may have become biologically adaptive — helping primates locate calorie-rich food sources in the wild.
The idea challenges the notion that humans’ relationship with alcohol is purely cultural. Instead, it suggests that the attraction to alcohol may be an inherited trait shaped by millions of years of evolution.
However, some researchers caution that modern alcohol consumption differs greatly from natural exposure in the wild, both in quantity and context. Still, the findings offer an intriguing perspective on how biology and behaviour intertwine across species.
Comprehension Questions
What evidence supports the “drunken monkey” hypothesis?
How might a preference for ethanol have been adaptive for early primates?
Why do some scientists disagree with this theory?
Personal Questions (C1–C2)
Does the “drunken monkey” theory change how you view alcohol?
Can cultural and biological explanations for human behaviour coexist?
What are the risks of applying animal research to human psychology?
Do you think modern drinking habits can be linked to evolution?
Could natural instincts still influence our food and drink choices today?
What does this theory suggest about the role of pleasure in evolution?
How do environmental pressures shape species’ behaviour over time?
In what ways might human innovation override evolutionary instincts?
How does this theory reflect on human self-control and moderation?
Do you think other habits — like sugar cravings — have similar origins?
How important is it for science to study our evolutionary past?
What ethical limits should apply to studying animals in the wild?
How might the media misrepresent this kind of research?
Could understanding our biological drives help reduce addiction?
Do you think human evolution is still happening today?
Answer Key (C1–C2)
Wild chimps regularly eat fermented fruit containing natural alcohol.
It may have helped them find high-energy, ripe food sources.
They argue that modern alcohol use is very different from natural exposure.
