Fate of 1,000 trafficked lab monkeys at center of US investigation in limbo

More than a thousand Cambodian monkeys at the center of a US government investigation into wildlife trafficking are at risk of being killed or returned to their country of origin, laundered and re-trafficked, animal welfare groups say.

The monkeys’ plight first came to light last year when the US Fish and Wildlife Service (FWS) asked the animal rights organization Peta about finding a sanctuary for 360 monkeys. Born Free USA, and the US Department of Justice (DoJ) later joined the discussions and the number of monkeys increased to over 1,000 as talks progressed.

Last week, however, discussions stalled when Peta learned on 13 March that the monkeys would instead be flown out of the US.

Under US law the monkeys can only return to their country of origin, Cambodia, said Dr Lisa Jones-Engel of Peta, but neither the DoJ nor the FWS has confirmed this.

The 1,000 or so juvenile long-tailed macaques are understood to be at a primate center in Houston, Texas, owned by Charles River Laboratories, a US company that buys, sells and tests on animals.

Charles River was recently drawn into a US government monkey trafficking investigation that saw several Cambodian officials charged by the DoJ last November for selling wild macaques, falsely labeled as farmed, to US research laboratories. Two unnamed US co-conspirators were also indicted.

Last Wednesday an apparent attempt to transport the 1,000 monkeys out of the US was thwarted by a Peta-organised protest demanding the monkeys be sent to a sanctuary.

Two days later Charles River told the Guardian they would be keeping the monkeys at their center. But, with the company blocked by the US government from selling or carrying testing on the animals until their non-wild status is confirmed, only three options are open to the US government, said Jones-Engel: “Seize and remove to a sanctuary, kill them, or allow re-export.”

During a 22 February conference call about company earnings, James Foster, Charles River CEO, announced the company had been subpoenaed by the DoJ on 17 February as part of its investigations. The company’s share price fell 14% on the day of his announcement.

Foster said Charles River was holding Cambodian monkeys but could not use them until the company proved to the DoJ they were captive bred. According to Peta, the shipment of 1,000 monkeys is worth approximately $30m. Foster also said the Cambodian supplier indicted in November was not one the company works with.

According to the DoJ indictment, at least 2,600 wild macaques are suspected of entering the USA lab system on false permits since 2018. The Guardian recently revealed that primates entering the USA from Cambodia could be carrying highly pathogenic diseases including one deemed a bioterrorism risk.

The US National Association for Biomedical Research recently revealed that the FWS had proposed new DNA testing of all imports to affirm the animals are not wild caught. This has delayed the release of thousands of animals into laboratories.

The US currently imports approximately 30,000 primates a year for research and testing, 60% are usually from Cambodia. The long-tailed macaque was elevated from “vulnerable” to “endangered” in 2022, in part due to exploitation by the research industries.

Any return of the monkey to Cambodia effectively means a return to those suspected of illegally exporting them, said Liz Tyson of Born Free, and involves the risk of a resale, potentially to Charles River or other US labs.

“The monkeys’ future if they are shipped back to Cambodia has no happy ending. Sanctuary in the US is the only way to guarantee their safety,” Tyson told the Guardian. “These young monkeys are scared, stressed, they are suffering right now,” added Tyson.

The US National Association for Biological Research has said that non-human primates remain a critical resource for the United States biomedical research. They warned that halting the import of Cambodian monkeys and additional complications, including worsening China-US relations and animal activist campaigns, mean “the drug development pipeline is grinding to a halt”. Long-tailed macaques are the primate species most often used for toxicology testing in chemical and drug development.

However, some studies show that primates are poor predictors of results in humans and in response, Congress recently passed the FDA Modernization Act which removes the legal requirement to test on animals before human clinical trials.

New, animal free methodologies like cell-based and “organ-on-chip” tests, are increasingly being utilized by scientists.

“The ill-conceived era of relying on stolen, diseased, distressed monkeys to cure human disease has never worked and is coming to an end, hopefully in time for these species to recover in their natural habitats,” said Jones-Engel.

The DoJ declined to comment any ongoing investigation and FWS said: “As a party to the Cites convention, the Service is required to uphold our Cites obligations. This includes not allowing wild caught macaques to be illegally imported into the United States in violation of the Treaty.”

Charles River said in an email it was “steadfastly opposed to the illegal importation of non-human primates that are not purpose-bred into the United States”.

Asked about the investigation, the spokesperson said Charles River has “operated under the belief that all shipments of NHPs [non-human primates] that we received satisfied the material requirements, documentation and related processes and procedures” required by international regulations.

The statement added that the company was cooperating fully with the US government.