Long-tailed macaques remain Endangered

And it’s worse than we thought

Each year, thousands of long-tailed macaques are bought and sold internationally to be used as subjects of biomedical testing and experimentation - an industry that poses a serious threat to the species’ survival. Once listed on the International Union for the Conservation of Nature’s Red List of Threatened Species as a species of  Least Concern, in 2020, long-tailed macaques were uplisted to Vulnerable status - and soon afterwards, in 2022, to Endangered. Primatologists studying the species in the wild had raised the alarm that long-tailed macaques were barreling down the road towards extinction, and that action was needed. 

Female long-tailed macaque (Macaca fascicularis) with her infant. Maternal care is essential for infant survival and social learning in macaque societies. (Image: Tanyahattingh)

This hasn’t been an easy idea for the biomedical industry to accept. The trade in these monkeys is worth over a billion dollars annually. Such use of long-tailed macaques, though riddled with concerns about the risks it presents to human health and safety, the threat it poses to nature, and the compromised welfare of the individuals involved, is deeply entrenched. The uplisting of long-tailed macaques to Endangered was likely to disrupt this industry, making it more difficult to source, trade, and make use of these monkeys. The industry, represented by the National Association for Biomedical Research (NABR), decided to fight back. They petitioned the IUCN to revoke the Endangered listing, claiming in a press release that the rigorous assessment that had been conducted by a team of scientists specializing in long-tailed macaque biology, ecology, and conservation, and which led to the species’ uplisting to Endangered, was “not based on peer-reviewed scientific information.” 

What followed has only strengthened the case for the long-tailed macaques’ Endangered status. Long-tailed macaque experts reconvened and reassessed all of the available information, incorporating new research, which had not been available at the time of their initial assessment. What they found was that the situation for long-tailed macaques has grown worse. 

On October 10, 2025, the new Red List assessment for the long-tailed macaque was published. When initially uplisted to Endangered in 2022, the classification was based primarily on a predicted 50% decline in population if present threat trends continued. The new assessment strengthens the classification because it has now been demonstrated that there has already been a decline of 50% or more over the past 30 years. Decline is expected to continue at a similar rate. 

This is awful news for long-tailed macaques. The good news, however, is that their classification as Endangered has been solidified, which is a necessary step in ensuring that the species is properly and effectively protected in the future.   

Congratulations to all of those who led and contributed to this important effort!