Drunk as a Monkey




Staring balefully into the bottom of an empty beer stein before he slides it toward the bartender, a stranger might—if he is on his third—tell me why he drinks. He might say he drinks because he is worried about his job, or his wife left him, or he cannot find any other way to disentangle his nerves from the day’s stress.

I will nod in total sympathy and admit that a glass of wine helps me face a party; a glass of champagne helps me celebrate; a stiff scotch gets me past temporary hysteria.

But neither of us will mention that we drink because we are monkeys.

Biologist Robert Dudley made a study of it. The idea came to him when, sitting on a veranda overlooking the rainforest, he tossed back a cold beer. As he drank, he watched spider monkeys plucking hog plums so ripe he could smell their sweet, fermented juice. The monkeys were no doubt feeling the same light buzz he was. His colleagues, meanwhile, had spent their careers studying drunk rats and mice, animals for whom sniffing out fermented fruit is alien behavior.

Darwin himself suggested that most monkeys would drink alcohol if it were available; he even knew a pub owner who regularly got his pet monkeys drunk. German biologist Alfred Brehm announced that African baboons could be lured by strong beer.

And so began The Drunken Monkey: Why We Drink and Abuse Alcohol, in which Dudley traces our “ancient tendencies as primates to seek out and consume ripe, sugar-rich, and alcohol-containing fruits.”

Produced by yeasts that feed on fruit sugars, alcohol is just a by-product of fermentation, one that helpfully kills off competing bacteria. Once tasted, though, it became the Holy Grail. In 1985, Anhui Daily reported that monkeys in the Yellow Mountains were tucking fruit into rock crevices so it could ferment, then returning months later to enjoy the results. On St. Kitts, green vervets are famous for stealing the tourists’ umbrella drinks.

Rhesus macaques, given access to booze, drank at the end of the day, as we do, and they would sometimes “stumble and fall, sway, and vomit,” reports study co-author Scott Chen of the National Institutes of Health Animal Center. He told Discovery News that the macaques varied in tolerance and thirst: “A few of our heavy drinkers, they would drink until they fell asleep.” Many drank until their blood alcohol was high enough for a state trooper to issue a citation. Most poignant, the heaviest drinkers were macaques who lived alone.

We share about 1,100 genes with monkeys. We might share their existential despair, too.

Tree shrews, who resemble the last living ancestor of the primates, hold their liquor better. The pen-tailed tree shrew returned to the Bertram palm tree as many as three times a night, every night, to suck fermented nectar from its blossoms. They are consuming the equivalent of nine glasses of wine, and it is 3.8 percent alcohol—rather a lot for a little shrew—yet they show no signs of drunkenness. Scientists suggest that their metabolism prevents cardiac risk, and the appetite stimulated by the alcohol (think of a good cabernet with a steak) keeps them robust.

Bats have strong heads, too: they fly straight after eating fermented fruit, and there is no “slurring” in their echolocation calls. Moose, on the other hand, need to stay away from the hard stuff. Years ago, a Swedish elk ate rotting apples, got a little woozy, and wound up stuck in the limbs of a small tree, three legs off the ground.

It is great fun seeing such photos or watching videos of loopy basset hounds and sleepy-drunk bears. (In Washington, one was captured with the hair of the dog: two more cans of Rainier Beer, plus some doughnuts.) When drunken bees return to the hive, “bouncer” bees will often block the entrance, even shoving them away until they sober up. And Bohemian waxwing birds love fermented rowan berries—and sometimes crash into buildings and die while under the influence.

Still, the biggest YouTube hits are often fakes. Dudley writes that “cavorting groups of inebriated baboons, sozzled chimps falling out of trees, and birds too drunk to fly” turned out to be animals who were deliberately gotten drunk by fratboy humans. And the drunken elephants who wrap their trunks around themselves in a maudlin daze? They do like the fruit of the marula tree. But an animal their size would have to consume 1,400 pieces of overripe fruit, or 7.1 gallons of marula juice, to feel the effect.

“People just want to believe in drunken elephants,” biologist Steve Morris told reporters.

I am about to prove that by pointing out that rice beer, more potent than marula fruit, did send a herd of elephants in India on a rampage, destroying sixty houses after they raided a villager’s still. And in China’s Yunnan province, two elephants were found napping in a tea garden after sipping about eight gallons of rice wine.

See? For some reason buried deep in our psyche, we like seeing other creatures partake of our pleasures and make fools of themselves. Maybe it eases the guilt. “Like any crime, drinking loves accomplices,” notes essayist Kris Bartkus. “A person will much more readily adopt their partner’s drinking habits than their bedtimes, fashions, or friends.”

Not me. I married a guy whose idea of a strong drink is a frozen banana daiquiri. But I do agree with Bartkus’s declaration that “the only good sip of beer is the first one. Every next sip merely chases that pleasure, while making us more and more certain that we can catch it.”

Are fruitflies caught by that trap? They smell alcohol, fly upwind to find the overripened fruit pulp, and lay their eggs on it. The larvae soak in a low level of alcohol as they develop, and it has a salutary effect, increasing longevity and egg output. But they are hardly addicted; offered an alternative of calorically enhanced food, they will take it. They want the carbs.

So here is what we know. Of the nonhuman animals who genuinely prefer booze, some drink responsibly, some metabolize efficiently, and some have a Problem. Vervet monkeys split into four groups: Social drinkers, who prefer their alcohol mixed with sweet fruit juice and drink with friends. Steady drinkers, the 12 percent who like it neat or with water and remain remarkably functional, prone to leadership positions. Binge drinkers, the 5 percent who drink fast, get into brawls, and end up comatose. Left to drink as much as they want, they will drink themselves to death. Which is inexplicable to the teetotalers, the 15 percent who would just as soon have a Sprite.

The parallels continue: juvenile vervets tend to drink more than the older monkeys. And does this vervet monkey research remind you of any other species? “Upon occasion, some animals drank to ataxia and unconsciousness; signs of withdrawal, including tremulousness, pacing, irritability and increased aggression, followed the abrupt discontinuation of ethanol availability.” The monkeys also showed, while voluntarily consuming alcohol, “a variety of changes in social interaction, including increased orientation to external stimulus, increased incidence of stereotyped aggression and of other stereotyped behaviors and decreased frequency of affiliative behaviors.”

We are primates. Our drinking habits are not as psychological as we like to think. Instead, we are self-soothing in whatever way our genes (and background) suggest we should. There are patterns: cross-cultural studies consistently show alcohol use at ritual events, such as weddings, funerals, ceremonial slaughter (football tailgates?), and dinner parties.

With his research, Dudley wanted to remove some of the stigma from alcoholism and demonstrate its physiological roots. Low levels of alcohol can even be helpful, he points out, in those built to tolerate the stuff. But our bodies can get us into trouble as surely as our brains can. And then comes the psychological toll.

“It flattens us,” writes Bartkus. “Suddenly, any joke, any lips, any song, any cheeseburger will do, in any order. And the other side too: a stone in your shoe hurts no worse than heartbreak.”

Tree shrews and bats can better afford to go numb.


Read more by Jeannette Cooperman here.