Explainer

How To Fight Monkeys

What should you do if you’re surrounded by angry macaques?

A Japanese macaque

The deputy mayor of New Delhi, India, fell off his balcony and died Sunday after being attacked by monkeys, his family members say. The city has around 10,000 monkeys, some of which have taken to roaming through government buildings as they steal food and rip apart documents. What should you do if monkeys are picking on you?

It’s like Mom said about muggers: Just give ‘em what they want. When monkeys get aggressive, it’s usually because they think you have something to eat. According to one study, about three-quarters of all the aggressive interactions between long-tailed macaques and tourists at Bali’s Padangtegal Monkey Forest involved food. If you are holding a snack, throw it in their direction, and they’ll stop bothering you. If you don’t have any food, hold out your open palms to show you’re not carrying a tasty treat or back away from the monkeys without showing fear. To diffuse the situation, don’t make eye contact or smile with your teeth showing—in the nonhuman primate world, these are almost always signs of aggression.

Monkey attacks are extremely rare in the wild; the creatures tend to be scared of us and often scamper away when a person gets within 100 feet. As monkeys lose their habitats around the world, though, they’ve started to live in closer proximity to humans, and that causes conflict.

Aggressive city monkeys will give you lots of warnings before an actual fight breaks out. First, the animals will look at you in the eyes, open their mouths, and bare their teeth. Rhesus macaques, the aggressive monkeys that cause a lot of the trouble in Delhi, will then warn you with a grunt. Next, they might fake a lunge toward you; this often causes a victim to lose his balance. If you’re still withholding food, they’ll grab at your knees and legs, and put their mouths on you so that you can feel their teeth. Finally, if you still won’t cooperate, they’ll sink their canines into you. The study in Bali found that most macaque bites don’t break the skin, but a wound could allow transmission of herpes B, which can be fatal to humans. Baboons, which sometimes attack humans in Africa, are much more dangerous: They’re bigger and less predictable, and they’re armed with 3-inch-long canines. Last year, a South African man’s forearms were ripped to the bone, and doctors dug out a baboon tooth during surgery.

What if you can’t or won’t appease the monkeys with food? You can try to chase them off by shaking a stick at them, but they might get violent if cornered. If they don’t budge, bop ‘em on the head; visitors to temples in India sometimes carry a stick for just this reason. Primatologists will sometimes send a macaque warning signal called the open-mouth threat. Basically, form an “O” with your mouth, lean toward them with your body and head, and raise your eyebrows. Female victims might seek protection in a group of men, since monkeys are somewhat afraid of males. But whatever you do, don’t freak out; those who scream, wave their arms, and run away are only going to make the macaques even more aggressive.

Despite all the monkey business, Delhi has refused to cull the macaques, which are sacred because of the Hindu reverence for Hanuman, the monkey god. Instead, the government has relocated some of the troublemakers and even brought in langurs, a mellower but larger monkey, to scare off the smaller macaques.

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Explainer thanks Agustin Fuentes of University of Notre Dame, Melissa Gerald and Janis Gonzalez of the Caribbean Primate Research Center, Andreas Koenig of Stony Brook University, and Dario Maestripieri, author of Macachiavellian Intelligence: How Rhesus Macaques and Humans Have Conquered the World.