In 2014, UC Berkeley biologist Robert Dudley wrote a book The Drunken Monkey: Why We Drink and Abuse Alcohol, proposing that our attraction to alcohol arose millions of years ago, when our monkey ancestors discovered that the smell of alcohol led them to ripe and nutritious fruit.

Recently, a new study led by Christina Campbell of California State University, Northridge (CSUN) supports this idea, which Dudley calls the “drunken monkey” hypothesis (假说).

In his book, Dudley laid out evidence for his idea, which showed that some fruits known to be eaten by monkeys have a naturally high alcohol content of up to 7%. But he did not have data showing that monkeys or apes preferentially sought out and ate fermented (发酵的) fruits, or that they digested the alcohol in the fruit.

For the newly reported study, the CSUN researchers analyzed the alcohol content in the fruits eaten and thrown away by black-handed spider monkeys at a field site, Barro Colorado Island in Panama. They found that the fruits routinely had alcohol concentrations of between 1% and 2%, a by-product of natural fermentation by yeasts.

Moreover, the researchers collected urine (尿液) from the free-ranging monkeys and found that the urine contained secondary metabolites (代谢产物) of alcohol. This result shows that the animals were actually using the alcohol for energy—it wasn’t just passing through their bodies. “They would get more calories from fermented fruit than they would from unfermented fruit. The higher calories mean more energy,” Campbell said.

The need for the monkeys’ high caloric intake may similarly have influenced human ancestors’ decisions when choosing which fruit to eat, Campbell added. “Human ancestors may also have preferentially selected alcohol-laden fruit for consumption, given that it has more calories,” she said.

Today, the availability of alcohol in liquid form, without the belly-filling pulp of fermenting fruit, means it’s easy to have too much of it. The idea that humans’ natural love for alcohol comes from our primate ancestors could help society deal with the consequences of alcohol abuse. “Heavy alcohol consumption can then be viewed conceptually as a disease of nutritional excess,” Campbell said.

【小题1】What is the “drunken monkey” hypothesis about?

A．Monkeys can hardly resist the attraction of alcohol.

B．It is difficult for humans to deal with drunken monkeys.

C．Our love for alcohol has something to do with monkeys.

D．Monkeys get drunk easily by eating fermented fruits.

【小题2】What can we learn from Dudley’s book written in 2014?

A．Monkeys prefer to eat fermented fruits.

B．The alcohol content of some fruits is very high.

C．It takes a long time for monkeys to digest alcohol.

D．Alcohol in the fruit influences monkeys’ digestive system.

【小题3】What did the researchers find in the urine samples?

A．Alcohol has obvious effects on monkeys.

B．Monkeys take in alcohol for more energy.

C．Alcohol can stay in monkeys’ bodies for long.

D．Unfermented fruit is much healthier for monkeys.

【小题4】What does the author want to tell us in the last paragraph?

A．The significance of the new research.

B．The ways to fight against alcohol abuse.

C．The problem of heavy alcohol consumption.

D．The effects of alcohol abuse on human health.