Evidence mounts of long-tailed macaques' dire conservation status
An IUCN ruling confirms the species appears to be endangered as recent analysis points to massive declines in its global population
A debate over the conservation status of the long-tailed macaque has raged in recent years, triggered by an International Union for Conservation of Nature (IUCN) Red List assessment that found the species to be endangered.
An IUCN committee delivered a decision on the issue on 24 June, confirming that existing evidence suggests the species does have this dire conservation status.
The ruling came after recent analysis indicated that the overall population of long-tailed macaques in their native range may have dropped by 80 percent in the last few decades.
A heavily exploited species
The conservation status of long-tailed macaques (Macaca fascicularis) garnered attention in 2022 when the IUCN Red List reassessed the species and concluded that it is endangered. According to the evaluation, the destruction and degradation of the species’ habitat, along with persecution, have contributed to its predicament. Liberal exploitation of the non-human primate, including for use in medical research, has also played a significant role, it said.
As I previously reported in The Ecologist, long-tailed macaques are “the most heavily exploited mammals on Earth among species protected in global trade, in terms of sales of live individuals.” A review article published in Frontiers in Conservation Science on 19 June pointed to the scale of exploitation. It highlighted that over 287,000 live individuals were traded internationally between 2015 and 2021.
The authors sourced these figures from the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which is the treaty body that regulates global trade in threatened wild animals and plants.
Additionally, countries reported hundreds of thousands of other long-tailed macaque trades across those same years, such as specimens like blood and tissue.
Industry challenges
The US’ National Association for Biomedical Research (NABR) formally challenged the Red List assessment of the long-tailed macaque in 2023. Such challenges are possible for all Red List assessments, with the IUCN Red List Standards and Petitions Committee ultimately responsible for settling any disputes.
Among other criticisms, NABR contended that the long-tailed macaque’s assessment failed to reach “objective scientific conclusions” and didn’t have the evidence to back up its classification of the primate as endangered.
The European Animal Research Association’s (EARA) executive director, Kirk Leech, similarly criticised the assessment, arguing that it contained mistatements, mischaracterisations, and subjective views. “This is emotion, masquerading as conservation, subjectivity rather than science,” he told me last year.
Leech spoke at a CITES Animals Committee meeting in 2023 to express EARA’s opposition to a US proposal for a review of trade in long-tailed macaques reportedly produced in captivity.
Most globally traded macaques are alleged to be born or bred in captivity. However, concerns have long circulated about wild-caught individuals being laundered through captive-breeding operations and overexploitation of wild populations for use as breeding stock in the facilities.
Given such concerns, along with high levels of trade in the primate and its endangered conservation status, the proposed CITES review aimed to scrutinise trade in long-tailed macaques from captive sources.
A high profile case hit the headlines in 2022 that cast some light on the issue. That year, US authorities indicted eight individuals who they claimed were involved in a monkey smuggling ring, whereby wild long-tailed macaques were allegedly traded from Cambodia to the US under the pretense that they were bred in captivity.
As Radio Free Asia reported, a jury acquitted one of those charged in March, Cambodian forestry official Kry Masphal. The seven other individuals, which includes another Cambodian official and six people connected to the firm Vanny Bio Research, are currently regarded as fugitives under US law.
The aforementioned review article, titled Global wildlife trade and trafficking contribute to the world’s nonhuman primate conservation crisis, said the macaque smuggling ring case:
suggests that trafficking within the context of legal trade may be more widespread than previously acknowledged.
Probe goes ahead
As scientists have highlighted, the laundering of wild individuals into supply chains of captive-bred primates risks undermining research. Considering this, it would be reasonable to expect the biomedical industry to support CITES’ review of trade, as the probe could help to ensure that facilities claiming to breed long-tailed macaques are acting legitimately.
Asked why EARA instead opposed the proposal, Leech stressed that reviews of trade can take years to complete. They involve “a lot of back-and-forth” between CITES and the countries concerned, he said, with the latter having to provide information like sustainability assessments and population surveys to demonstrate the conservation status of the species. “We are not sure that this review will assist medical research,” stated Leech.
When I asked what the industry itself does to ensure that it sources legitimately captive-bred macaques, the EARA executive director said the European scientific community imports most primates from accredited breeding facilities in Africa.
Leech also pointed to a changed “international landscape” for long-tailed macaque supply chains due to increased demand and changes to China’s role in the trade post-Covid, which he said had led to a shortage of primates for research.
Despite EARA’s opposition to the probe, CITES parties, meaning signatory countries, ultimately decided that scrutiny was necessary. They moved forward with a review of trade in long-tailed macaques reportedly produced in captivity from the countries Cambodia, Indonesia, Vietnam, and the Philippines.
Initial findings from the review are due to be discussed at a CITES Animals Committee meeting in July.
IUCN decision
The IUCN Red List Standards and Petitions Committee delivered its ruling on NABR’s challenge to the 2022 Red List assessment on 24 June. Contrary to the industry body’s assertions about the assessment lacking supportive evidence, the committee found that existing information does appear to indicate the long-tailed macaque is endangered. In relation to projected decreases in the species’ population, it said:
the available information appears to support suspected declines of at least 50% over the next three generations
The Red List assessment identified suspected declines of 40 percent over the last three generations and at least 50 percent in the next three generations. The projected declines were the basis for the species’ endangered classification.
However, the committee found that the assessment lacked “clear organization” of the available information and included emotive language that was inappropriate for the Red List. For these reasons and others, the committee requested a do-over of it, with the reassessment due in eight months’ time.
The long-tailed macaque’s endangered classification will remain in place until then, at which time the reassessment will be reviewed by the committee and the primate’s Red List category will be updated accordingly.
NABR welcomed the reassessment. Its president, Matthew R. Bailey, said:
NABR is pleased that the IUCN will reassess its designation of long-tailed macaques as ‘Endangered’.
The IUCN’s decision to uplist long tailed macaques to ‘Endangered’ in 2022 was not justified, nor supported by scientific information.
Action for Primates also responded to the committee’s decision. On behalf of the nonprofit, co-founder Sarah Kite commented:
We welcome this ruling by the IUCN, which has maintained the Endangered conservation status of the long-tailed macaque.
Rather than expressing concern for the serious negative impact their activities have had on wild populations, the research and toxicity testing industry is trying to downgrade the conservation status in order to obtain the monkeys as readily and cheaply as possible.
New research
The committee instructed the Red List Assessor who will carry out the reassessment to include newly available information and “information that contradicts the assessment conclusions” in their analysis.
This would presumably include a 2023 study that found long-tailed macaques to be among four “hyperabundant” species in Southeast Asian forested areas around palm oil plantations. It’s important to note, however, that this research grouped the long-tailed macaque with another species, the pig-tailed macaque, in its density estimates. Additionally, in some instances where the study conveyed data on the species separately, such as in bar charts showing the results of 117 published camera trapping studies, long-tailed macaques appeared to have distinctly low estimated abundances.
I reached out to various authors of the paper about their findings but did not receive a response.
Moreover, conservation biologist and primatologist Nadine Ruppert, who was not involved in the research, told Mongabay that overall populations of all four species spotlighted in the paper – long-tailed macaques, pig-tailed macaques, wild boar, and bearded pigs – are struggling due to the various threats they face.
NABR also commissioned an assessment of the long-tailed macaque’s conservation status, with the findings published in a commentary paper in the American Journal of Primatology in December 2023. This review challenged the idea that the primate is at risk of extinction and found evidence “to support a major decline in the abundance of long-tailed macaques” to be lacking.
Nevertheless, the paper stressed that the lack of data does not mean that macaques have not declined, only that “the extent of any decline or increase in abundance remains unknown.”
The long-tailed macaque is a synanthropic species, meaning it can live in close proximity to people and in landscapes altered by human behaviour.
Population assessments for synanthropic species like the long-tailed macaque can involve overestimations, as the 2022 Red List assessment highlighted. This is because the species’ visibility in places where humans are can make them seem more abundant than they are in reality. Indeed, accurately estimating populations of any free-ranging wild species can be difficult, particularly when aiming to do so in the least intrusive ways.
Considering these issues, a group of 37 researchers set about developing a new scientific model to estimate the highest likely populations of large-bodied and terrestrial, or semi-terrestrial, native wild animals who live in groups. To test whether their approach worked, the researchers applied it to the long-tailed macaque.
Adding to the body of new information available since the 2022 Red List assessment, Science Advances published the findings on 24 May.
Drastic reductions
As the researchers explained, the model essentially combines scientific observations with citizen science and can be applied to many species. It utilises species-specific information, such as behaviour and habitat preference, alongside data sources, such as camera traps, direct sightings, and transect surveys, to determine population estimates.
When applied to long-tailed macaques, the model accurately reflected published data on populations in two protected areas, one in Cambodia and the other in Vietnam.
Overall, the researchers estimated a global population of approximately one million long-tailed macaques. This points to an 80 percent reduction in the macaques’ population over the last 35 years compared to a prior assessment that put their global numbers at five million individuals around 1990.
If accurate, this means the species is in even worse shape than the 2022 Red List assessment indicated.
The model’s estimate is for the long-tailed macaque’s native range in Southeast Asia, with introduced populations living in the wild elsewhere, such as in Mauritius, which were not included in the tally.
True number could be lower
The analysis comes with some caveats. The researchers highlighted, for instance, that they sourced records about the presence of long-tailed macaques from various channels, including citizen science platforms, which “lack expert verification.” They also said the accuracy of estimates may differ between countries, from high to lower confidence, due to where the model derived its information from. The included data primarily came from Cambodia, Malaysia, Laos, and Vietnam.
However, they said the model would likely produce overestimates rather than underestimates, due to it being calibrated to a highly studied protected area, the Keo Seima Wildlife Sanctuary (KSWS) in Cambodia, where macaque populations are better safeguarded. In other words, the estimates may represent a best case scenario for long-tailed macaques.
In its ruling, the IUCN Red List Standards and Petitions Committee also highlighted that results of a 2022 survey of KSWS’ long-tailed macaque population have emerged since the last Red List assessment.
The committee pointed out that the 2022 survey result “increases the recent population decline trend” in KSWS, with the survey report highlighting that the primate’s population was down by 49-55 percent in the 12 years up to that year. The committee said adding this information into the reassessment would “strengthen support” for the assessment outcome.
Safeguarding measures
Action for Primates’ Kite says that concerns about the long-tailed macaque’s conservation status have been increasing for several years. Pointing to the value of IUCN assessments in protecting imperiled species, she adds:
The greater the conservation status, the more measures and policies will be put in place to try to secure the future of the species from over-exploitation.
There is no shortage of ideas about how to better safeguard long-tailed macaques and other primates from overexploitation in recently published papers.
The primate trade review article called for an end to the use of wild-caught primates by the biomedical industry and increased oversight of breeding farms. The paper further urged the industry to “actively promote the use of alternatives” to primate testing. Alternatives include research and testing involving human cells and data rather than non-human animals.
Such alternatives are gaining traction as a way forward on both ethical and public health grounds. This is because although testing on animals is deeply entrenched in the research industry, its results frequently fail to translate to humans, according to Pandora Pound, research director at Safer Medicines Trust. In her 2023 book RAT TRAP: The capture of medicine by animal research and how to break free, the researcher highlighted:
A shocking ninety per cent of all experimental drugs fail in human trials despite having first passed tests in animals, and in many fields the statistics are even worse.
Securing primates’ future
Another paper titled Perspectives on Conservation Impacts of the Global Primate Trade was published in the International Journal of Primatology in May. It also offered recommendations, such as improved documenting of the use of wild-caught primates in restocking breeding farms and more transparency in trade overall. It further suggested that one to five percent of research grant funding for experiments involving primates be put towards conservation of the utilised species.
The paper highlighted that trade in primates, whether it be for research, meat consumption, the pet trade, or traditional medicine, can pose a public health risk, including by diseases being spread through supply chains.
It also stressed that exploitation can impact the ecosystems that primates are removed from, with knock on effects for the climate too. Long-tailed macaques and other primates fulfil important ecological functions, including through their seed dispersal and roles as both predator and prey.
In some cases, predation by long-tailed macaques can be detrimental to other species. For instance, the introduced population living in Mauritius, which is also heavily exploited, is among the predators of the endangered Mauritian kestrel. Conservation efforts can, however, help to mitigate these issues, such as the provision of predator-proof nesting boxes.
Above all, overexploitation of primates puts the species themselves at risk, the perspectives paper said. It warned:
It is only by growing the free-ranging populations and protecting their natural habitats that we can ensure that primate species will survive past the end of this century.
Great piece Tracy. The shameful lobbying of exploitative industries to downplay the risks to populations of a wild species is straight out of playbooks used around the world of course - including here in the UK where Red Listed birds are still on 'quarry' lists used by the shooting industry.