How Many Humans Are Killed by Monkeys Each Year?

No reliable global tally exists. Unlike sharks, bears, or snakes, monkey-caused human deaths are not systematically tracked by any international health agency, and most fatal encounters go unrecorded in countries where they happen most frequently. The available evidence, scattered across case reports and regional surveillance data, suggests the number of direct deaths is small in absolute terms, likely in the low dozens annually worldwide. But the indirect toll from diseases monkeys transmit through bites and scratches adds an uncertain and probably larger layer to that figure, one that researchers openly admit they cannot quantify.

Why No One Can Give You a Number

The biggest obstacle to answering this question is that monkey-related deaths are simply not counted in most of the world. Rabies surveillance, which would capture many fatal monkey-to-human disease transmissions, relies on passive reporting in most countries. A review published in PLOS Neglected Tropical Diseases noted that rabies cases in nonhuman primates are not even notifiable diseases in many nations, meaning they are never entered into official statistics. Rules about submitting animal specimens for rabies diagnosis are often weak and may cover only species considered economically important, leaving primate-transmitted rabies largely invisible to public health systems.¹

Direct deaths from physical attacks face the same documentation problem. A fatal monkey attack on a child in a rural village in South Asia or sub-Saharan Africa may be reported locally but never makes it into any centralized database. Forensic case reviews that do exist tend to be individual reports published years after the event. The result is that researchers working in this area freely acknowledge the data gaps and treat any count as a floor, not a ceiling.

How Monkeys Actually Kill People

When monkeys do cause human deaths, the mechanism is rarely what people imagine. Most people picture a vicious mauling, but monkeys, even the larger macaque species, lack the body mass to overpower a healthy adult. The victims of fatal direct attacks are overwhelmingly infants and very young children. A forensic review of primate-caused injuries documented cases in which monkeys snatched babies from caregivers. In one case, a macaque entered a room through an open door, grabbed a six-month-old girl from her mother’s lap, and carried her to a rooftop terrace before dropping her. The infant died from blunt cranial trauma after hitting the ground. Other documented infant deaths involved bites and drowning.²

This phenomenon of “baby theft” by monkeys has been reported across multiple countries and involves both macaques and, in rarer instances, chimpanzees. Wild chimpanzees have been documented specifically hunting human infants for food, though chimpanzees are apes rather than monkeys and represent a distinct category of risk.² For adults, direct physical attacks by monkeys are almost never lethal on their own. The real danger for adults lies in what follows the bite.

The Diseases That Follow a Bite

A monkey bite or scratch that barely draws blood can still set off a chain of events that kills. The three biggest threats are rabies, herpes B virus, and ordinary bacterial infection that spirals out of control.

Rabies

Rabies is the most significant monkey-transmitted killer globally, though separating monkey-transmitted rabies deaths from the broader rabies toll is nearly impossible in practice. In India, which has both the world’s highest rabies burden and enormous populations of free-ranging macaques, a multicenter study of animal bite victims at anti-rabies treatment centers found that monkeys were the second most common biting animal after dogs, accounting for about 3% of all bite cases.³ That 3% might sound small, but India treats tens of millions of animal bites a year, so the absolute number of monkey-bite victims seeking care is substantial. Not all of those bites come from rabid animals, but when they do and post-exposure treatment is delayed or unavailable, the outcome is almost always death. The problem is compounded by the fact that rabies in nonhuman primates goes significantly underreported, so neither the true number of rabid monkeys nor the resulting human deaths is well documented.¹

Herpes B Virus

Herpes B virus is an alphaherpesvirus that circulates naturally in macaque species. In macaques, it causes mild disease similar to cold sores in humans. In people, it can be devastating. When human infection does occur, typically through a bite, scratch, or contact with macaque saliva, it can cause severe brain inflammation. Mortality rates in untreated cases have historically been very high. The virus can also remain dormant for extraordinary lengths of time. A case report in the American Journal of Tropical Medicine and Hygiene described a patient who developed severe meningoencephalitis from herpes B reactivation 54 years after the original monkey bite.⁴

Fortunately, confirmed human herpes B cases are rare, numbering only a few dozen in the medical literature over several decades. But the rarity may partly reflect underdiagnosis in regions where macaque bites are common and diagnostic testing is limited. The virus represents a specific occupational hazard for laboratory workers handling macaques and, increasingly, a risk for tourists at sites with semi-wild macaque populations.

Secondary Bacterial Infections

Even without exotic viruses, a monkey bite can kill through ordinary bacterial infection. Monkey mouths harbor a range of bacteria, and deep puncture wounds from canine teeth create ideal conditions for infection. One documented case involved a 47-year-old man who developed necrotizing fasciitis, a rapidly spreading soft-tissue infection, after a monkey bit his leg. Within a week he was in septic shock with foul-smelling discharge from the wound site, followed by fever with chills and rigors.⁵ Necrotizing fasciitis from any cause has a high fatality rate even with aggressive surgical treatment. In settings where medical care is delayed, a seemingly minor monkey bite wound can become life-threatening within days.

Where Monkey Attacks Happen Most

Monkey-human conflict is concentrated in South and Southeast Asia, parts of sub-Saharan Africa, and, to a lesser extent, Central and South America. India stands out because of its enormous population of rhesus macaques and bonnet macaques living in cities, around temples, and along roadways. Urban macaques in Indian cities like Shimla, Delhi, and Varanasi have adapted to human food sources and can be boldly aggressive, particularly toward people carrying groceries or street food.

Southeast Asia has its own hotspots. Bali’s temple monkey forests are among the most studied sites for monkey-human interaction. At the Sangeh monkey forest in Bali, a survey of people living and working near the temple found that nearly 30% reported having been bitten by a macaque at least once, and 39% had been scratched. The injuries overwhelmingly involved hands and occurred when people were holding food. Among those who reported feeding monkeys, the injury rate was roughly eight times higher than among those who did not.⁶ A separate observational study at the Padangtegal monkey forest documented 420 aggressive interactions between tourists and long-tailed macaques in just two months. Adult and subadult male macaques were disproportionately responsible for these encounters.⁷

These Bali numbers are striking: hundreds of aggressive encounters per month at a single tourist site, with about a third of regular visitors eventually bitten. Multiply that across the hundreds of temples, parks, and urban zones across Asia where macaques live alongside people, and the total number of bite and scratch injuries annually is clearly in the hundreds of thousands. The overwhelming majority of those injuries are minor, but the sheer volume means that some fraction will result in serious complications, and a smaller fraction will be fatal.

What Triggers the Aggression

If you read enough of the research on monkey-human conflict, one pattern emerges with almost monotonous consistency: food is the trigger. A study of macaque-human interactions in Singapore found that two-thirds of all encounters happened when a person was carrying food or items that looked like food, such as plastic bags. Another quarter occurred when a human deliberately provoked the monkeys. Only about 8% of interactions had no clear human-triggered context.⁸

The Bali data tell the same story from a different angle. At Sangeh, 94% of injuries occurred when the person was holding food at the time.⁶ Farmers, who work around food crops, had the highest exposure rate of any occupation, more than six times higher than the baseline. Photographers, who spend long hours near the macaques without food, had a moderate rate. Merchants, who sit at covered stalls, had a much lower one.

This has a practical implication for anyone visiting areas with wild or semi-wild monkeys. The single most effective thing you can do to avoid a bite is not carry visible food and not feed the animals. Tourists who buy bananas to hand-feed monkeys at temple sites are, statistically, putting themselves at dramatically higher risk. And the risk is not just a scratch. Those macaques may carry herpes B virus, and Bali’s temple macaques have tested seropositive for it at high rates.

Children and Infants as Targets

The vulnerability of young children to monkey attacks deserves its own attention because it changes the calculus of risk. Adults bitten by a monkey usually sustain a wound to the hand or forearm. Children and infants face a qualitatively different threat. Infants can be physically carried away, as the case studies of “baby theft” illustrate. Even without snatching, a macaque that bites a toddler’s face or head can cause injuries that would be relatively minor on an adult’s arm but life-threatening on a small child.

The forensic literature notes that fatally injured infants in primate attacks have died from three mechanisms: bites to the head and face, falls after being carried to a height, and drowning when dropped into water.² These scenarios are almost exclusively documented in settings where monkeys have free access to living spaces, which is common in parts of India and Southeast Asia where macaques enter homes through open windows and doors. Parents in those regions are generally well aware of the risk and take precautions, but the cases that do occur tend to be sudden and difficult to prevent.

Comparing Monkeys to Other Animals

To put monkey-caused deaths in context, consider the animals that kill the most humans. Mosquitoes kill hundreds of thousands of people each year through the diseases they transmit. Snakes kill an estimated 80,000 to 140,000. Dogs, primarily through rabies, account for tens of thousands of deaths annually. Crocodiles, hippos, and elephants each cause hundreds of deaths per year in Africa and Asia. Against this backdrop, monkeys rank far down the list of dangerous animals. Even a generous estimate of monkey-caused deaths, including rabies transmitted through monkey bites, would probably place the annual total below a hundred worldwide.

But that comparison can be misleading in specific locations. If you live in a rural Indian village where macaques regularly enter homes, or you work at a Southeast Asian primate research facility, monkeys are a more immediate and frequent source of physical threat than almost any other wild animal in your environment. The risk is extremely localized, which is part of why it gets so little global attention.

The Tourist Dimension

International tourism has created a new category of monkey-human contact that barely existed a generation ago. Monkey forests, temple complexes, and wildlife parks where visitors hand-feed primates have become enormously popular across Southeast Asia. At these sites, the monkeys are habituated to humans and have learned to associate people with food. That habituation makes them bolder, not friendlier.

The research from Bali is particularly revealing. At Padangtegal, observers documented adult male macaques engaging in aggressive behavior toward tourists far more often than expected based on their proportion of the monkey population.⁷ These are not small animals; adult male long-tailed macaques can weigh 5 to 9 kilograms and have prominent canine teeth capable of inflicting deep puncture wounds. Tourist injuries at these sites are treated locally and rarely enter any systematic database, contributing further to the undercount of monkey-related harm.

The herpes B exposure risk adds another layer. At Sangeh, the macaques in closest contact with tourists have been shown to carry the virus. A bite or scratch from one of these animals is not just a wound management problem; it is a potential exposure to a virus with serious consequences. Most tourists are unaware of this. Travel medicine clinics in departure countries sometimes brief travelers, but on-site warnings at monkey tourist attractions are often minimal or absent.

Emerging Spillover Risks

Beyond the diseases monkeys already transmit to people, researchers are watching for the next potential spillover event. One area of concern involves simian arteriviruses, a group of viruses that circulate in African monkeys and can cause hemorrhagic fever in some primate species. A 2022 study published in Cell demonstrated that one of these viruses, simian hemorrhagic fever virus, can successfully enter human cells by binding to the human version of its receptor protein. The researchers noted this means the virus has already overcome the first biological hurdle needed for spillover to humans.⁹

This does not mean a spillover is imminent or that a new pandemic from monkeys is likely. Cell entry is one step in a long chain of events required for a virus to spread effectively among humans. But the finding highlights why researchers take monkey-human contact seriously beyond the immediate bite-wound level. Every physical contact between a wild primate and a person is a potential bridge for pathogens, and the expanding overlap between human settlements and primate habitat means those bridges are multiplying. Bushmeat hunting, deforestation pushing primates into agricultural areas, and the tourism industry all increase the number of contacts. The next monkey-to-human disease transmission event may ultimately matter more, in terms of human lives lost, than all the bites and scratches combined.

What Practical Precautions Actually Work

If you are visiting or living in an area with free-ranging monkeys, the research points to a few evidence-based precautions. Do not carry visible food or feed the animals. At Bali’s monkey forests, people who fed macaques were injured at nearly eight times the rate of those who did not.⁶ Plastic bags, which monkeys associate with food, should be kept inside a closed backpack. Do not make direct eye contact with macaques or bare your teeth, both of which can be interpreted as threats. If a monkey grabs something from you, let it go; injuries spike when people try to snatch items back.

For residents in areas where monkeys enter homes, keeping doors and windows screened is the most effective physical barrier. Infants and small children should not be left unsupervised in rooms with open access points, particularly in regions where macaques are known to enter dwellings. If bitten, the wound should be washed thoroughly with soap and running water for at least 15 minutes, and medical evaluation for rabies post-exposure prophylaxis should be sought promptly. If macaques are the species involved, the treating physician should also be made aware of herpes B virus risk, which requires a different antiviral protocol than standard wound care. The Singapore research underscored that human behavior is the primary driver of most monkey-human interactions, meaning the risk is, to a meaningful degree, within your control to manage.⁸