Similar report from Europe highlights growing demand and shrinking availability of nonhuman primates for biomedical studies
The supply of monkeys for research is shrinking, and access to remaining animals is becoming increasingly unreliable. That’s the dire message of a U.S. National Academies of Sciences, Engineering, and Medicine report released today, which concludes that the situation is compromising critical biomedical research now—and will continue to do so well into the future.
The new report is the strongest government statement yet on the precarious state of monkey research. Sponsored by the U.S. National Institutes of Health (NIH) and based on information from government agencies, National Primate Research Centers, academic institutions, and more than 200 scientists who use nonhuman primates, it finds that nearly two-thirds of U.S. researchers have reported challenges in obtaining monkeys. This has delayed studies, forced scientists to use fewer and less ideal animals (heavier or younger than the norm, for example), and, in some cases, has led to studies being abandoned. Monkey prices have also skyrocketed, the report finds, in extreme cases tripling to $24,000 per animal—putting these primates out of reach for many researchers.
The shortage has developed as Asian sources of monkeys have dried up and domestic primate centers have been unable to expand their breeding programs, the report says. The report also suggests that China is competing with the United States for the purchase of nonhuman primates from Southeast Asia, further straining supply. “Relying on importing these animals from other countries is unsustainable,” the report argues.
A European report released last month reached similar conclusions. The demand for research monkeys is so high in EU nations, and the supply is so low, that the European Union will not be able to meet its goal of creating sustainable domestic breeding colonies of these animals. “Unless a solution is found, nonhuman primate research in Europe will dwindle and even stop in certain places,” says Kirk Leech, executive director of the European Animal Research Association. “We’re moving into a very uncertain world.”
The reports come during perhaps the most tumultuous 3-year period in the history of monkey research. The U.S. uses about 70,000 monkeys per year in research; the EU about 5000; and the U.K. about 2000. In the early days of the COVID-19 pandemic, China stopped exporting research monkeys, shutting off a key pipeline for the United States and United Kingdom. At the time, the U.S. was receiving 60% of its imported monkeys from China. The vast majority of these were cynomolgus macaques (or cynos), a species mostly used by private industry for drug and vaccine research.
The U.S. and other countries were able to make up for some of the shortfall by increasingly sourcing monkeys from Southeast Asia and the Indian Ocean island of Mauritius, but other challenges awaited. The pandemic spiked demand, sucking up monkeys for vaccine research. In 2022, Air France became the last major airline to refuse to transport monkeys for research, increasing the difficultly of getting these animals to labs. And that same year, the International Union for Conservation of Nature classified cynos as endangered, citing growing demand from the research industry and prompting fears that the animals would become even harder to import.
Then, in November 2022, Cambodia—which had largely made up for the shuttered Chinese pipeline by supplying more than 29,000 cynos in 2020, the vast majority to the U.S.—was hit with a major smuggling scandal. U.S. investigators charged several individuals with illegally exporting hundreds—and potentially more than 2000—wild-caught cynos to the U.S. and falsely labeling them as captive-bred.
Since then, two of the world’s largest suppliers of cynos—Inotiv and Charles River Laboratories—have stopped their imports from Cambodia. Both companies tell Science they are working on new procedures that would ensure any monkeys they import have a legitimate provenance. (Some groups have claimed that the U.S. Fish and Wildlife Service is blocking monkey imports, but the agency tells Science in an email that it “has not implemented any new policies banning the importation or exportation of non-human primates.”)
The U.S. and EU breed some monkeys domestically—a few thousand in total, and mostly for academic researchers—but these facilities, too, have struggled to meet demand. A 2018 NIH report found that because of a growing need for neuroscience, infectious disease, and aging research, the demand for rhesus macaques—the primary monkey species used in U.S. academic labs—was likely to outstrip supply in the near future. That shortage came to pass in 2021, and the U.S. government invested more than $30 million extra in monkey breeding at its seven National Primate Research Centers. But it wasn’t enough to abate the shortage, and an additional $30 million requested by U.S. President Joe Biden was eliminated from a 2022 spending bill.
To combat supply problems, the National Academies report says the U.S. should expand domestic breeding programs and increase coordination between the various domestic monkey suppliers. The U.S. should also continue to invest in nonanimal models such as “organ on a chip” technology, which the report says are looking more promising than ever, though not quite ready for prime time.
I don’t see any short-term solution to this problem.Kirk Leech
executive director of the European Animal Research Association
Beyond that, however, the suggestions are vague. Kenneth Ramos, the report committee chair, says his committee was only tasked with making conclusions, not specific recommendations.
Joyce Cohen, associate director of animal resources at the Emory National Primate Research Center, says even if all of the money and infrastructure for a domestic breeding program materialized tomorrow, it could take 4 to 5 years to start getting even some of the animals academic scientists need. Expanding current primate research centers to meet that need could cost hundreds of millions of dollars. Still, Cohen hopes these challenges won’t dissuade NIH from seriously considering the investment. “You have to start somewhere.”
The EU’s problems are even more stark, Leech says. Its solution also lies in more domestic breeding. But unlike the U.S., the EU cannot legally import wild-caught monkeys to start or supplement breeding colonies. That’s a huge obstacle, he says. “I don’t see any short-term solution to this problem.”
Eric Kleiman, a researcher at the Animal Welfare Institute, an animal advocacy group, says he hopes the supply crisis will force scientists and government agencies to more seriously consider—and invest in—alternatives to animals in research. “Increased domestic breeding is not a panacea.”
Major pharmaceutical and biotech companies contacted by Science either declined to comment on the supply issue or did not respond. But a U.S. consultant on industry and academic monkey research says these companies are getting “a lot more serious” about investing in domestic breeding. “There is a rising level of concern that this is a major issue,” says the source, who has worked in the field for decades but asked not to be named because of concerns about damaging relationships with his clients. “There have been discussions about whether and how they should all work together to ensure supply.”
But as the crisis intensifies, he says companies may need to start asking themselves whether the amount of money and effort it’s going to take to meet demand is worth it—or even possible. If not, the biomedical industry may need to rethink its priorities, he says: “Are we in the drug discovery business, or are we in the monkey breeding business?”