Primate Species Most Used in Laboratories Again Declared Endangered by Oversight Body; PETA Urges Protection
For Immediate Release:
October 10, 2025
Contact:
Tasgola Bruner 202-483-7382
In a blow for the primate experimentation industry, the long-tailed macaque today was again listed as “endangered” on the 2025 Red List of endangered species – at an even higher rate of decline than the previous assessment – by the International Union for Conservation of Nature (IUCN), the world’s leading experts on endangered species. In a letter sent today, PETA demands that the U.S. Fish and Wildlife Service (FWS) assess the data and extend the species Endangered Species Act protections.
PETA points out that the FWS has ignored conclusive evidence—including findings from its own investigation that ended in 2022—while populations crash under the weight of the primate experimentation trade.
Tens of thousands of long-tailed macaques are imported from Asia to U.S. laboratories annually despite the species’ catastrophic decline and evidence that using them is not leading to significant improvements in human health.
In June 2022, the IUCN listed long-tailed macaques as endangered after reviewing data from more than a dozen primate scientists, including PETA’s Dr. Lisa Jones-Engel. In April 2023, PETA first pressed FWS for an assessment of the long-tailed macaque population with a formal petition signed by dozens of primate experts, including the late Dr. Jane Goodall. FWS declined to act. The following year, animal experimentation industry lobbyists petitioned the IUCN to delist the species, claiming the population was booming and alleging a conflict of interest by the scientists who submitted the population data. IUCN found no conflict of interest but called for a new population assessment by international primate scientists. The new assessment found that the rate of decline of long-tailed macaques is even higher than the 2022 assessment.
PETA resubmitted its petition to FWS in January 2025 with new evidence, including a Science Advances publication indicating that long-tailed macaque populations in Asia are 80 percent smaller than expected. It also cites a population estimate from the Wildlife Conservation Society Cambodia showing the long-tailed macaque population in that country’s protected Keo Seima Wildlife Sanctuary has declined by at least 49 percent—nearly half—since 2010.
“The IUCN’s decision to again list the long-tailed macaque as ‘endangered’ is a decision based on science, not spin, and squelches the politically driven attempts by lobbying groups to muddy the facts, manufacture doubt, and continue capturing and killing these monkeys,” says Dr. Lisa Jones-Engel. “PETA strongly urges the U.S. Fish and Wildlife Service to do its job and provide long-overdue federal protection to these monkeys before they’re driven to extinction by the animal experimentation industry.”
PETA obtained documents in December 2024 revealing that current and former FWS employees and animal experimentation lobbyists tried to inappropriately influence the review process for listing the species under the U.S. Endangered Species Act and persuade the agency to base its decision on data provided by the experimentation industry, rather than formal assessments from Dr. Jones-Engel and other primate scientists.
A burn pile containing diseased long-tailed macaques at a monkey breeding warehouse in Cambodia that received smuggled monkeys and supplied U.S. laboratories.
PETA encourages the public to help protect long-tailed macaque populations by urging the U.S. Centers for Disease Control and Prevention to ban the importation of monkeys for use in laboratories.
PETA—whose motto reads, in part, that “animals are not ours to experiment on”—points out that Every Animal Is Someone and offers free Empathy Kits for people who need a lesson in kindness. For more information, please visit PETA.org or follow PETA on X, Facebook, or Instagram.
