Booming demand for laboratory animals in China’s pharmaceutical industry is fueling a massive illegal trade in wild-caught monkeys, with thousands of live primates smuggled into the country for use in clinical trials, a Sixth Tone investigation has found.

The smuggling networks not only threaten wild monkey populations across Asia; they also pose a grave danger to public health, given the large number of diseases carried by wild monkeys and the ease with which they can spread to humans.

China’s pharmaceutical industry has grown at breakneck speed since 2015, and this has sent demand for lab monkeys soaring. Each clinical trial for a new drug typically requires up to 60 primates.

For safety reasons, laboratories are only allowed to use monkeys bred in captivity by licensed breeding companies. Wild monkeys often harbor a cocktail of deadly diseases, including tuberculosis, measles, and malaria.

But China’s breeding farms have been unable to keep up with rising demand, leading to acute shortages of lab monkeys. Prices for captive-bred long-tailed macaques — the main primate used in drug trials — have skyrocketed more than 2,000% in China since 2014, reaching 230,000 yuan ($32,000) per macaque in 2023.

Organized crime networks have emerged to take advantage of the shortages. Wild macaques have been poached in their thousands — both in China and abroad — and illegally certified as captive-bred animals. The “laundered” monkeys can then be sold at a huge profit for use in clinical trials.

A Sixth Tone analysis of Chinese judicial records and media reports uncovered a dramatic rise in cases involving gangs smuggling long-tailed macaques into China since 2016. Multiple breeding centers have been busted for buying wild-caught monkeys and passing them off as captive-bred animals.

Such large-scale monkey laundering operations represent a serious public health risk, scientists told Sixth Tone. It makes the possibility of a zoonotic spillover event — where a virus mutates and jumps from macaques into the human population — more likely, they warned.

Pharma boom

Chinese demand for laboratory monkeys first began to spike after the Chinese government overhauled its drug manufacturing regulations in 2015. The reforms — which sped up the approval process for new drugs — transformed the country into a global center for the pharmaceutical industry in just a few years.

China’s leading biopharma companies grew explosively between 2016 and 2021; their combined value on major stock exchanges rose from just $5 billion to $400 billion during that period, according to consulting firm McKinsey. They also began running far more clinical trials.

In 2017, China’s National Medical Products Administration received 484 applications for investigational new drug trials. By 2021, this figure had risen to 1,159 — not far off the roughly 1,500 IND applications the U.S. Food and Drug Administration receives each year.

This led to a spike in demand for laboratory animals, which quickly overwhelmed China’s breeding companies. The country has more than 50 licensed monkey breeding centers, but the industry has struggled to ramp up production. 

Monkeys grow and reproduce slowly. A macaque must reach the age of 2 to be sellable, and it takes a minimum of four years for a female to reach childbearing age. They can’t give birth more than twice a year, and usually only give birth to a single baby each time.

Until 2016, China had been a major net exporter of lab monkeys, with the country’s breeding farms sending tens of thousands of primates abroad each year. Within a few years, the situation had radically altered.

Chinese breeding firms were unable to satisfy domestic demand, and thousands of monkeys were being imported to China every year from breeding farms in Cambodia, Indonesia, and Vietnam. Prices for captive-bred macaques in China rose steeply.

Then came the pandemic, and the shortages became far more severe. In January 2020, China banned the trading of wildlife to prevent potential future zoonoses. All imports and exports of monkeys were prohibited, cutting off a large chunk of Chinese pharma companies’ lab animal supply.

By 2021, there were reportedly around 30,000 captive-bred long-tailed macaques available for clinical trials in China, but demand from the pharmaceutical industry was 1.5 times or even twice as high, domestic media estimated. 

China’s pharma companies responded by reserving lab monkeys several generations in advance, and buying up Chinese breeding centers so they could gain control over their supplies. 

Wuxi AppTec, a major Chinese pharmaceutical conglomerate, became China’s largest monkey breeder after acquiring Suzhou Kanglu Biotechnology in an 804 million yuan deal. Pharmaron and JOINN Laboratories, two other large pharma firms, also invested in monkey breeding operations. 

China reversed its ban on monkey imports in mid-2022, but supplies of captive-bred macaques remain extremely tight. Prices soared from 14,000 yuan per long-tailed macaque in 2017 to 150,000 yuan last year. By 2023, they had reached 230,000 yuan.

Sixth Tone contacted Wuxi AppTec, Pharmaron, and JOINN Laboratories for comment, but received no response.

Shadow trade

The shortages have created enormous new incentives for criminal activity, as gangs are able to make millions of yuan by passing off wild-caught monkeys as captive-bred.

It typically takes between two and three years and costs around 8,000 yuan to raise a captive-bred monkey to marketable size, Sixth Tone’s sister publication The Paper reported. But wild monkeys can be caught at a minimal cost and immediately put into circulation.

Monkey laundering operations have been a serious issue in China for a long time. In a 2011 report on laboratory monkeys, the State Forestry Administration called for a “severe crackdown” on smuggling to “effectively prevent the entry of smuggled and illegally captured monkeys into scientific research and commercial use under the label of captive breeding.”

The 2012 edition of the report went even further. It not only ordered a “severe crackdown on smuggling”; it also introduced new restrictions on imports. Previously, Chinese breeding companies had been allowed to replenish their stocks by importing wild monkeys from abroad, as long as only the wild monkeys’ offspring were used in laboratories. But this practice needed to be outlawed in order to “adjust” the domestic monkey breeding industry, the report said.

Chinese judicial records and media reports, however, suggest that the monkey laundering trade continued to expand at a rapid pace over the following years. 

Between 2002 and 2015, authorities in the Guangxi Zhuang Autonomous Region — a southwestern Chinese province bordering Vietnam — seized a total of 1,696 long-tailed macaques that had been smuggled into China. Since 2016, the year that China’s pharma boom began, they have seized a staggering 15,829 smuggled long-tailed macaques.

In reality, the number of monkeys being smuggled across the border is likely even higher, as most shipments evade the authorities, experts told Sixth Tone.

“Seizures made by law enforcement are just the tip of the iceberg,” said Astrid Andersson, a conservation biologist and wildlife trade expert at the University of Hong Kong. “The true volume of the illegal wildlife trade is likely much higher than what is detected.”

Chinese media reports provide a vivid picture of how extensive monkey laundering operations have become. In September 2022, a police patrol in Baise — a city in Guangxi next to the Vietnam border — reportedly stumbled across a pile of plastic crates hidden in the jungle. 

Inside, the officers discovered 47 long-tailed macaques, which were worth an estimated $1.4 million. They had been brought across the border by smugglers and were awaiting a pickup.

One seizure in 2019 made national headlines. The police, acting on a tip-off, discovered that traffickers had brought 2,745 long-tailed macaques from Vietnam into Guangxi. According to prosecution records, the group had even set up a medical technology company in China with all the necessary licenses to keep and breed primates, and were laundering their wild macaques through that business.

The potential profits were huge. At the time, a wild long-tailed macaque reportedly cost around 5,000 yuan in Vietnam, while a captive-bred animal across the border was worth 20 times that amount.

Sixth Tone contacted public security bureaus in multiple counties and municipalities bordering Vietnam in Guangxi, as well as the provincial capital, Nanning, but received no response.

Monkey laundering operations go beyond smuggling long-tailed macaques into southwest China. Chinese law enforcement is also trying to crack down on domestic gangs poaching and laundering rhesus macaques — a native Chinese species that is widely used in clinical trials for new vaccines.

Chinese authorities have prosecuted criminals for poaching or illegally possessing more than 1,700 rhesus macaques since 2002, according to China’s judicial database. Though it is unclear how many of those monkeys were intended for laboratory use, recent Chinese media reports suggest that large-scale laundering of rhesus macaques is taking place.

In February 2023, police in Ya’an — a city in southwest China’s Sichuan province — announced that they had dismantled a nationwide monkey poaching and laundering network. The groups had been capturing rhesus macaques in Sichuan, licensing them as captive-bred via a registered company, and then selling them on, the officers said.

Another high-profile recent case was the downfall of Wang Zhengwu, known in China as the “Monkey King.” The biopharma company Wang founded, Hengshu Biotechnology, bred thousands of monkeys for use in clinical trials both domestically and overseas.

But, in 2021, Wang was arrested after an investigation found that Hengshu Biotechnology had been buying wild rhesus macaques from poachers in Sichuan province for 2,000 yuan each. The company was then reportedly falsely certifying the monkeys as captive-bred and selling them on for 70,000 yuan.

Sixth Tone contacted Hengshu Biotechnology by phone, and asked whether the company was now operating normally. A company representative replied “no,” before terminating the call.

Hidden dangers

The growth of the trade in wild monkeys is creating severe environmental and public health risks, experts told Sixth Tone.

Long-tailed macaques used to be common across Southeast Asia. In 2006, the wild population was estimated at around 3 million, but it has since fallen by more than half due to widespread poaching. The species was classified as endangered in 2021.

The global demand for laboratory monkeys is a main driver of the poaching. Long-tailed macaques are not only being smuggled into China; a large number of laundered macaques are also being brought into the United States from Cambodia, media reported last year.

Malene Hansen, a researcher at the University of Copenhagen who studies long-tailed macaques, said that the species may soon disappear from the wild completely unless action is taken.

“According to our surveys, in some areas they are not there anymore,” she said. “I think this species will rapidly go extinct, because the demand is so intense and the price is so high.”

The trade also endangers people. Wild monkeys carry a wide range of bacteria and viruses, and many of them can be easily transmitted to humans — as the recent monkeypox epidemic demonstrated.

Lisa Jones-Engel, a leading American primatologist, told Sixth Tone that monkeys imported into the United States were found to be infected with “tuberculosis, leprosy, measles virus, herpes B, Salmonella, Shigella, Yersinia, Campylobacter, Ebola-Reston virus, simian hemorrhagic fever virus, malaria, yellow fever virus, simian immunodeficiency virus, and simian retrovirus.” 

There is not only a risk of humans contracting diseases such as malaria and tuberculosis from wild monkeys; public health experts are also concerned about monkey viruses jumping into the genetically similar human population — a process known as zoonosis.

This has already happened on multiple occasions. The most infamous example is simian immunodeficiency virus (SIV), which was transmitted to people in the late 19th century and led to the emergence of the human immunodeficiency virus (HIV).

In a recent paper, Chinese scientists Jiang Xinjie, Fan Zhenyu, Li Shijia, and Yin Haichang said the monkeypox epidemic had shown it was “imperative to understand the risks of the potential transmission and spread of emerging infectious diseases from non-human primates to humans.” They added that further research on the subject is “urgently needed.”

One virus of particular concern is herpes B. Practically all wild macaques carry the virus — which is closely related to the human herpes virus — without any ill effects, but it can be deadly to people.

There have been several recorded incidents of humans being infected with herpes B after coming into contact with monkey saliva, urine, or faeces. In most cases, this resulted in death.

The latest such infection took place in China. In April 2021, a veterinarian dissecting a rhesus macaque contracted herpes B and died.

Researchers are also worried about the potential for an outbreak of a simian hemorrhagic fever virus — a family of viruses that is lethal to macaques, causing severe internal bleeding. Though no human infections have yet been documented, a 2022 paper in the scientific journal Cell said hemorrhagic fever viruses are “poised for spillover to humans,” as they require “no major adaptations to human hosts.”

The wild monkey trade provides ideal conditions for monkey viruses to spread and jump to people. Hundreds of macaques, having been separated from their relatives and troop members, are packed into filthy boxes and deprived of food and water as they are smuggled across borders.

The “immunity-crushing stress” the animals experience weakens their resistance to viruses, said Jones-Engel. Their urine and saliva often contains higher than usual concentrations of viral particles, putting people who handle them at an elevated risk of being infected, she added.

In January, scientists at the University of Adelaide in Australia issued a stark warning over the potential danger posed by the global trade in wild primates. Loose regulation of the wildlife trade, they said, “could be paving the way for the next pandemic.”

For Jiang, Fan, Li, and Yin, it’s crucial that authorities “strengthen the inspection and quarantine of experimental animals.” They added that “health professionals, national authorities, and the media should more readily divulge information to the general public to raise awareness” about the public health risks posed by wild monkeys.

Sixth Tone contacted the China Center for Disease Control and Prevention for comment on the risks associated with monkey laundering, but received no response.

Contributions: Li Wei; infographics: Luo Yahan; editor: Dominic Morgan.

(Header image: A rhesus macaque on Mount Emei, Leshan, Sichuan province, 2020. VCG)