PETCHABURI, Thailand — Swaths of butterflies flutter around Chalong Thongsong and his team of rangers and researchers as they walk along a muddy trail into the forest of Kaeng Krachan National Park. The biggest of Thailand’s national parks, Kaeng Krachan is home to more than 450 wild animal species.

Arriving at a camera trap chained to a tree, the rangers work quickly: one unlocks the camera cage and removes the memory card, which another plugs into a laptop. A civet, a pack of dholes, and even a family of elephants appear on the screen. At the third camera-trap site, they find what they’re looking for. Gathered around the laptop, they watch, mesmerized, as a leopard strolls along the very footpath they’re now standing on.

“We estimate that, within the 1,000-square-kilometer [nearly 400-square-mile] study area, there is a density of around 3-4 leopards per 100 km²,” says Chalong, the park’s technical forestry officer. That works out to about 8-10 leopards per 100 mi2.

A critically endangered subspecies

The Indochinese leopard (Panthera pardus delacouri), a subspecies native to the Southeast Asia mainland, is listed as critically endangered on the IUCN Red List. The latest population estimate ranges from 77 to 766 individuals — highlighting both the subspecies’ rarity and the difficulty of studying it.

“It is almost impossible to accurately estimate leopard population numbers at a broad scale with any degree of precision,” says Gareth Mann, who leads the leopard program at Panthera, a global NGO focused on wildcat conservation. Dense forest habitats and a high proportion of melanistic individuals, commonly known as black panthers, make Indochinese leopards particularly difficult to survey: researchers rely on each leopard’s unique markings to identify individuals, but in melanistic leopards, these are only detectable under UV light.

Kaeng Krachan National Park is part of the Northern Tenasserim Forest Complex, which straddles the border between Thailand and Myanmar, and has been identified as one of the two remaining strongholds for Indochinese leopards. The other lies in Peninsular Malaysia. A former stronghold in Cambodia’s Eastern Plains has been lost in recent years, with leopards now believed to have gone functionally extinct in Cambodia, Vietnam and Laos. These losses have been driven by poaching, the illegal wildlife trade, and a vast snaring crisis: some 12 million traps are thought to be scattered across protected forests in the three countries, mostly to meet demand for wild meat.

Research led by Susana Rostro-García, a researcher affiliated with Panthera and the University of Oxford in the U.K., finds that the Indochinese leopard, once widespread across Southeast Asia and southern China, now survives in just 2-6% of its historical range. In that 2024 paper, Rostro-García and co-authors assess the largest camera-trap study for leopards in Southeast Asia to date, concluding that the prognosis for the Indochinese leopard (and the even more endangered Javan leopard) is “increasingly bleak.”

According to Rostro-García, “the loss of the Indochinese leopard could also lead to a sequence of additional species extinctions.” Because it’s more adaptable than other large carnivores, the Indochinese leopard fulfills a critical ecological role. Its disappearance could “result in changes in the numbers and distributions of smaller carnivores and prey,” which could in turn “cause dramatic changes in ecosystem structure and potential imbalances,” she says.

The attention gap

Few conservation projects in Southeast Asia focus on leopards, despite their critical status. By contrast, there are many initiatives devoted to tigers: Tigers are endemic to Asia and often seen as “symbolic of Asian conservation,” Mann says. As the “bigger, more dominant cat,” they tend to draw more attention, just as lions do in Africa.

Unlike tigers, whose populations have declined more uniformly across their range, Indochinese leopards show variable densities, says Robert Steinmetz from WWF Thailand. In some locations, populations have dropped dramatically or vanished altogether, whereas in others, like Kaeng Krachan, they remain relatively high. “This variability in leopard populations creates the perception that they are doing better than their more charismatic cousin,” Steinmetz says.

The problem with relying on charisma for conservation is that it “leaves a species vulnerable to subjective whims about what is charismatic,” he says. Focusing on “ecological communities rather than single species,” he adds, “would allow conservationists to address this gap.”

Rebuilding prey and habitat

Back in Kaeng Krachan, Chalong and his team hold on to the sides of their four-by-four as it bumps along a dirt track. They stop repeatedly to clear the piles of broken branches left by passing elephant herds. After 15 minutes, the car emerges into a clearing of long grass and a lake. Chalong jumps out of the vehicle and picks a piece of bone off the ground. “It’s from a sambar deer,” he says, the leopard’s preferred prey in Kaeng Krachan.

“This watering hole was built about 13 years ago to support wildlife. All kinds of species come here to eat and drink: elephants, deer, gaur …” Chalong says, adding that such spaces benefit leopards by supporting prey populations. “When a leopard comes, all the other animals quickly disappear,” he chuckles. This particular project is funded by the Wildlife Conservation Society.

To bolster prey populations, WWF is developing saltlicks and grasslands and reintroducing at-risk ungulates such as sambar deer (Rusa unicolor) in leopard habitats such as Thailand’s Mae Wong National Park, Khlong Lan National Park and Salakpra Wildlife Sanctuary. They’re also working to reconnect forests, restoring corridors between the Western Forest Complex, home to most of Thailand’s leopards, and the Mae Ping-Om Koi Forest Complex, where leopards have recently been recorded. For Steinmetz, “maintaining connections between source sites and depleted sites” is crucial in the long term to give leopards a chance at recovery.

Building on this, Panthera and WWF are now surveying Thailand and Malaysia to identify areas with the greatest conservation potential and possible corridors between them. “This is a critical first step,” Mann says. He adds he hopes the findings will feed into national and regional action plans for Indochinese leopard conservation.

Conservation planning must account for how leopards interact with other predators, especially as recent conservation successes have boosted tiger populations in parts of Thailand . “As tiger numbers increase, leopards may be pushed to the fringes of protected areas, which could increase conflict with local communities,” Mann says.

However, research by Steinmetz and WWF suggests leopards adapt when sharing territory with tigers . “They narrow their diet niche, focusing on primates and smaller prey, thereby reducing competition,” he says. They also avoid tigers spatially. Ensuring habitats include areas with dense cover and fewer large prey helps leopards keep out of tigers’ way.

For now, Mann says tiger densities remain too low to pose a danger to leopards. Because many of their threats overlap, tiger conservation often benefits leopards too: “It’s certainly not a case of having to choose tigers or leopards at this point.”

Caught in the trade

Just half an hour from Kaeng Krachan, Wildlife Friends Foundation Thailand (WFFT) rescues wild animals from the illegal trade, a leading cause of the Indochinese leopard’s decline. Tom Taylor, head of operations, walks through the sanctuary’s wildcat section. A 16-year-old female Indochinese leopard called Prik strolls over to greet him before settling into a leafy corner. The greenery is so dense it’s hard to spot the other leopards inside the enclosure.

“In total, we have five females,” Taylor says. The leopards, alongside 12 tigers, were rescued in 2023 from a northern Thai zoo linked to the illegal wildlife trade .

Though there is certainly global and regional demand for leopards and their parts — whether for use in traditional medicine, or for zoos and private collections — Panthera’s Mann says that “much of the harm being done to leopards is a result of the demand for other ‘wild products,’ which can impact leopards through incidental snaring, prey depletion, or general habitat degradation.”

Drawing from Panthera’s work in Africa, Mann argues that strengthening the security of protected areas where leopards live “would almost certainly be an effective intervention” in Southeast Asia. But the region’s vast forests, rugged mountains and dense vegetation make policing these areas far more difficult, providing ample cover for poachers. Over the long term, Mann says, real progress will also depend on reducing demand for wildlife and wildlife products.

A few meters away from Prik’s enclosure at the sanctuary, a poster features pictures of wildcats and their descriptions in Thai. WFFT also organizes visits from local schools, Taylor says. The focus of these visits is not only to expose children to wildlife, but to teach them about the consequences of poaching and consuming wildlife products. “We really hope we can change attitudes by working with younger generations,” Taylor says.

A future in question

After decades of decline, the Indochinese leopard now clings to survival in a greatly reduced range. Mann says he remains cautiously hopeful: “There are vast areas of habitat available. Though many would need to be restored, the fact that they exist provides cause for optimism.”

Recovery in Cambodia, Laos or Vietnam would require reintroduction. “The most likely site for a reintroduction is probably the Eastern Plains landscape of Cambodia,” Mann says. “But success would depend on a major reduction in poaching.”

For now, conservationists agree the priority is to safeguard stronghold populations in Thailand, Myanmar and Malaysia.

While conservation plans are drawn up at regional and international levels, the day-to-day work of protecting leopards falls to the rangers on the ground. Soon after Chalong and his team arrive at the watering hole, rain begins to fall. A drizzle turns into a downpour, and they retreat to the park cafeteria. Over plates of steaming rice and pad kra pao, the rangers swap leopard stories. Leopards are occasionally seen pacing along the park’s main trail.

“We used to avoid sharing photos of leopards, because we didn’t want hunters to target them,” Chalong says. “Now we are more selective with visitors, and we try to share more photos so people will want to protect them.”

After lunch, the rangers pull on their raincoats and head back into the forest to check the last camera traps. The rain hasn’t stopped, and neither has their work.

Banner image: The Indochinese leopard (Panthera pardus delacouri), a subspecies native to the Southeast Asia mainland, is listed as critically endangered. Image by Ana Norman Bermúdez.

Citations:

Rostro-García, S., Kamler, J. F., Sollmann, R., Balme, G., Augustine, B. C., Kéry, M., … Macdonald, D. W. (2023). Population dynamics of the last Leopard population of eastern Indochina in the context of improved law enforcement. Biological Conservation, 283, 110080. doi:10.1016/j.biocon.2023.110080

Rostro-García, S., Kamler, J. F., Sollmann, R., Balme, G., Sukmasuang, R., Godfrey, A., … Macdonald, D. W. (2024). Leopards on the edge: Assessing population status, habitat use, and threats in Southeast Asia. Biological Conservation, 299, 110810. doi:10.1016/j.biocon.2024.110810

Odden, M., Wegge, P., & Fredriksen, T. (2010). Do tigers displace leopards? If so, why? Ecological Research, 25(4), 875-881. doi:10.1007/s11284-010-0723-1

Harihar, A., Pandav, B., & Goyal, S. P. (2011). Responses of Leopard Panthera pardus to the recovery of a tiger Panthera tigris population. Journal of Applied Ecology, 48(3), 806-814. doi:10.1111/j.1365-2664.2011.01981.x

Duangchantrasiri, S., Sornsa, M., Jathanna, D., Jornburom, P., Pattanavibool, A., Simcharoen, S., … Ullas Karanth, K. (2024). Rigorous assessment of a unique tiger recovery in Southeast Asia based on photographic capture-recapture modeling of population dynamics. Global Ecology and Conservation, 53, e03016. doi:10.1016/j.gecco.2024.e03016

Steinmetz, R., Seuaturien, N., & Chutipong, W. (2013). Tigers, leopards, and dholes in a half-empty forest: Assessing species interactions in a guild of threatened carnivores. Biological Conservation, 163, 68-78. doi:10.1016/j.biocon.2012.12.016

Phumanee, W., Steinmetz, R., Phoonjampa, R., Bejraburnin, T., Bhumpakphan, N., & Savini, T. (2021). Coexistence of large carnivore species in relation to their major prey in Thailand. Global Ecology and Conservation, 32, e01930. doi:10.1016/j.gecco.2021.e01930

Nijman, V., Morcatty, T., Smith, J. H., Atoussi, S., Shepherd, C. R., Siriwat, P., … Bergin, D. (2019). Illegal wildlife trade — Surveying open animal markets and online platforms to understand the poaching of wild cats. Biodiversity, 20(1), 58-61. doi:10.1080/14888386.2019.1568915

Uddin, N., Enoch, S., Harihar, A., Pickles, R. S. A., & Hughes, A. C. (2023). Laundered alive? The transnational trade in wild felids through Bangladesh. Global Ecology and Conservation, 41, e02356. doi:10.1016/j.gecco.2022.e02356

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Isabel Esterman Editor

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AnimalsBig CatsBiodiversityCatsConservationCritically Endangered SpeciesEndangered SpeciesEnvironmentHabitatHabitat LossLeopardsMammalsSaving Species From ExtinctionTropical ForestsWildlifeWildlife ConservationAsiaSoutheast AsiaThailandPanthera

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