On the trail of Borneo’s bay cat, one of the world’s most mysterious felines

There is a photograph of the bay cat I can’t get out of my head. In it, the cat looks intensely right at the viewer, its sun-yellow eyes sporting two dark lines running up from them as if someone had applied makeup. In the mix of light and shade, its coat passes from brown to orange to blood red. Its long tail is tipped in white. The animal is in a dingy cage, littered with dead rats, but that doesn’t detract a bit from the cat’s majesty and strangeness.

Jim Sanderson, the world’s leading expert on small wildcats, took the photo in 2008. The cat, which had previously been kept in a cage in a gas station, was being held in a private menagerie in Sarawak, Malaysian Borneo.

Sanderson, who founded the Small Wild Cat Conservation Foundation, says the cat’s owner “knew what he had.” And what he had was arguably the world’s most elusive wildcat — and among the most endangered. A few days later, the cat was gone — likely sold for a pile of cash into the illegal wildlife trade. Its end was probably ignominious.

The Borneo bay cat (Catopuma badia) is so rare, elusive and strange that after its discovery, it vanished from science for more than 60 years. Today, the bay cat remains stubbornly difficult to even find, no less research or conserve.

It makes the snow leopard look conspicuous.

What we know, and what we don’t

“The bay cat is a black hole, and we don’t even know how to start to study the species, it is so elusive,” says Oliver Wearn, a biologist and conservation consultant. “They are about as elusive as any mammal can be.”

There are a few things we do know. C. badia is the only feline endemic to Borneo, and its appearance is distinctive, making it easy to tell apart from the other four cat species living there due to its “bay” (reddish-brown) coloring — though there are other color variants — and due to its super-long tail.

Sebastian Kennerknecht, photographer and founder of Cat Expeditions, a global cat tourism group, notes that the bay cat “kind of looks like a mini puma but isn’t even in the same genus.” The animal is most closely related to the Asian golden cat (Catopuma temminckii), but these two felines likely evolved down different paths more than 3 million years ago.

Oh, and we know it lives in the forest.

And that’s about it. We don’t know any behavior basics: the ecological niche it fills, what kind of forest it prefers, what it eats, whether it’s an arboreal cat or ground hunter, how much territory it needs or how the species mates and rears young.

The biggest mystery, and the one holding up conservation efforts: Why is this cat so frustratingly rare?

To date, Sanderson’s 2008 photos of that male feline remain some of the best in the world. And one day, if the worst happens, that photo may be one of few records of a never-known feline.

‘It does exist’

Despite years doing field research, biologist Susan Cheyne has never seen a bay cat. There’s even “some speculation that it doesn’t exist,” she says. Cheyne is the co-founder and director of research at Borneo Nature Foundation International (BNF), which works in Kalimantan, Indonesian Borneo.

Kennerknecht, who’s led tours in Borneo, has seen all of the island’s elusive cat species in the wild — except the bay cat. “Even most of the super-serious cat chasers out there have not yet seen this species,” he says.

When I ask Cheyne if she knew anyone who’d ever seen it in the wild, she says, “No,” but then adds emphatically, “It does exist.”

Alfred Russel Wallace, famed biologist and the second father of evolution, was the first scientist to come across the bay cat, sending a skin and skull back to the U.K. in 1856. Scientists collected five more specimens over the next few decades, but after 1928, the bay cat vanished.

“There have been a few rumors of the cat’s continued existence, some unsuccessful searches, and the occasional unconfirmed sighting,” reads a 1993 paper in Oryx.

That changed on Nov. 4, 1992, when a nearly dead female bay cat was brought to the Natural History Museum in Sarawak. Indigenous people had trapped and kept the cat for several months.

“The specimen was about the size of a domestic cat with an extremely long tail. It weighed 1.95 kg [4.29 lbs], but was in a thoroughly emaciated condition with wasted muscles and protruding bones,” according to the Oryx paper, announcing the discovery.

Charles Leh, then curator of the museum, preserved the specimen. Its pitiful captivity and death had done one thing: It confirmed the species hadn’t gone extinct in the prior 64 years.

So, how do we know it still exists? Because researchers and conservationists like Cheyne and Wearn continue to capture fleeting bay cat images on camera traps, albeit rarely — really rarely. Collectively, researchers have recorded it less than a hundred times, according to Wai-Ming Wong, the director of small cat conservation science at the cat NGO Panthera, one of the few groups working on the bay cat.

And those appearances have been devilishly sporadic. BNF, for example, spent 16 years camera trapping in Sabangau National Park, easily catching all four other Borneo cat species on camera, in “good numbers,” says Cheyne — but no bay cat. Although, the researchers have recorded the cat in five other protected areas in Indonesian Borneo.

Wearn and colleagues, using camera trap data obtained in the Kalabakan Forest Reserve in Sabah, tried to assess bay cat population density, estimating about three bay cats per 100 square kilometers (38.6 square miles) — a smaller number than for clouded leopards described in a 2022 paper published in Methods in Ecology and Evolution. They also found bay cats to be the fastest cats in Borneo, moving at a dizzying speed of 1.2 kilometers (0.75 miles) per hour as opposed to the next fastest, the far larger clouded leopard, at 0.9 kilometers (0.56 miles) per hour.

“The low density and fast movement speed implies that the bay cat might have a very large home range, perhaps in excess of the clouded leopard,” says Wearn, noting that his colleagues rarely photographed the same bay cat twice — true for every researcher I speak to for this story. “Alternatively, the bay cat might occur very patchily, due to very specific habitat or diet requirements. We really don’t know at this point.”

Wearn notes these density statistics are “informed guesstimates” based on camera trap data and on assumptions about a medium-sized cat. “The 2022 study was the first time anyone has been able to estimate the density of a whole community of animals [including species beyond the bay cat] from camera traps,” he says of the paper.

Not everyone has enough encounters to even attempt density estimates.

“We have never really, in any single place, got enough photographs to actually get any kind of decent density estimate,” says Cheyne of the parks in Kalimantan, noting that five or six photos were the most they ever got from a particular site.

Habitat loss leads to decline

Whatever the density, scientists say they believe the bay cat population is in decline, as with many other mammals in Borneo. Humans have destroyed about half of Borneo’s forests since the 1970s. So, logically, a forest-dependent species like the bay cat would have probably seen a dramatic drop in numbers in recent decades.

The IUCN Red List, which categorizes the bay cat as endangered, estimates its potential area of occupation likely shrank by a third by 2010. IUCN also estimates that there’s fewer than 2,500 bay cats left — and that was in 2016.

It also seems likely bay cats aren’t found in peat forests, which, if confirmed, rules out a vast portion of the island’s habitat. The species also has never been recorded in an oil palm plantation, which means it may suffer from a lack of connectivity across Borneo.

“Bay cats need vast areas of connected and relatively intact habitat to survive. … Roads, oil palm plantations and infrastructure development are major constraints on this,” says Wearn.

The one bright spot? Scientists have recorded the bay cat in secondary forest, which means it may be able to hold on in some places disturbed by humans.

The cats are becoming harder to find in some locales. For example, Wong says his colleagues failed to photograph a bay cat in the Deramakot Forest Reserve in Sabah during their most recent round of camera trapping. This is worrying because Panthera has been camera trapping there since 2014, and its scientists’ sighting of bay cats caused them to believe the area was a “potential stronghold” for the species.

But Wong says he’s not yet “alarmed,” given how hard the animals are to photograph.

Besides habitat loss, the bay cat is also potentially threatened by hunting, with people killing it for food or due to a perceived sense that it may prey on local livestock, especially chickens. Killing of its prey (whatever that may be) could also be impacting the cat. Andrew Hearn, a biologist with WildCRU, says he’s also gravely concerned that snaring — common across Borneo — could be a “significant threat,” sharing an anecdote of a local hunter having unintentionally snared a cat before letting it go. Given its low population density, any killing by people could be devastating for bay cat survival.

Conservation — but how?

While organizations are actively working on small cat research — such as the Small Wild Cat Conservation Foundation, Panthera and Re:wild — no group currently has a research or conservation effort specifically focused on the bay cat.

But how do you conserve a species about which so little is known? That question plagues any researcher working tangentially on the bay cat today.

To conserve the animals, “We need to know where they are and what they need to survive. We aren’t doing a good job at these two most basic questions,” says Wearn, who suggests conservationists need to determine a “suitable study site to do some in-depth research on the species.”

He also suggests trapping an animal and radio collaring it, “assuming the significant ethical risks of this are judged to be worth it.” This is something conservationists did with the Amazon Rainforest’s short-eared dog, shedding new light on this super-rare predator.

Cheyne says scientists also need to reach out to local communities for more information. “I’m sure there’s a whole load of local knowledge out there: historical local knowledge about these cats that just hasn’t been tapped into.” She adds that it would be useful to seek out stories, myths or legends surrounding the species.

Wong suggests larger-scale camera trap surveys might shed a brighter light on the species. He also thinks eDNA may be an option, but hurdles await anyone pursuing that route such as the difficulty of knowing where the cats may be and the rapidity with which organic material breaks down in the tropical environment.

However, to accomplish any of this, conservation groups would need the funding and resources to focus exclusively on the bay cat. Some money for that could come soon, since small wildcats got a big funding boost in 2021 when the Ayers Wild Cat Conservation Trust pledged millions for small wildcats.

Still, Panthera’s Small Cats Program has the same total level of funding for all 33 small- to medium-sized cats as just one of its programs for a big cat, including the puma, which is of least concern (Puma concolor). This reflects the simple fact that big cats are far more popular with donors and the public — and thus receive much more funding — than small and medium-sized cats. While some groups are funding work on small cats, due in part to the efforts of Jim Sanderson, most large conservation NGOs still aren’t.

Bay cats “are quite hard to fundraise for … because they’re so rare, [and] it’s difficult to get results,” explains Wong. What if, for example, Panthera raised a big pot of money to study bay cats, set out a hundred camara traps and didn’t get a single photo? “With a super-rare species, a donor will give me money. … [But] what will I have to show for that?”

To a scientist, not finding a cat is still useful, Wong notes, as it rules out where the animal isn’t. But in terms of funding, a crapshoot for a species most people have never heard of is a hard sell.

When it come to the bay cat, Sanderson says, conservation action isn’t impossible. The big barrier is our ignorance concerning what is threatening the animal.

“No one can tell me specifically what the threats are,” Sanderson says. “Is it bushmeat hunting? We have solutions working in Africa for the African golden cat. Is it habitat loss? I don’t think so because the bay cat is found in degraded forest. Is the threat retaliatory killing for stealing chickens? We have solved this problem many times over — a hammer and chicken wire.”

Sanderson says the focus should be on one primary question: Why is this cat vanishing? Then put money toward fixing the problem. “I am not saying [basic] research is unnecessary,” Sanderson adds. “I’m saying let conservation needs — like threat assessment — motivate research questions. The answers will be immediately useful.”

Close contact

In 2003, biologist Andrew Hearn headed to Borneo for his first field work conducting orangutan surveys in Kalimantan with local researchers. At the start, he and his colleagues found some boaters and persuaded them to take the team upriver deep into the forest.

But Hearn quickly discovered the boaters had their own agenda: They “began loading the largest chainsaws I had ever seen onto the boat,” at which point the researchers realized they were traveling with illegal loggers. But making the best of a poor situation, the team sailed upstream, and while the loggers cut trees, the scientists counted orangutans.

And then it happened.

“One morning, before breakfast, I walked a few meters from camp to sit and take in the air… when a small red cat walked out in front of me,” recalls Hearn, who today is a clouded leopard researcher at WildCRU. “I quickly sketched it before it sauntered off, and I returned to chat with my new logger friends about this strange red cat, which, at the time, I was unsure if it was domestic or wild! The head of the gang causally replied, ‘Yes, it’s kucing merah,’ the red cat.”

Weeks later, Hearn took his drawing to Jim Sanderson. “He looked at me and said, ‘That’s the bay cat, Andy.’” The encounter led Hearn to focus his life’s work on Asia’s wildcats. Of all the researchers I talk to about the bay cat, Hearn is the only one who has seen a live, wild bay cat in person.

And he’s never seen one since.

Banner image: Photo of the captive bay cat in 2008. These images of the captive animal remain some of the best close-ups of the bay cat ever taken. Image by Jim Sanderson. 

Extremely rare bay cat filmed in Borneo

Citations:

Sunquist M, Leh C, Hills DM, Rajaratnam R. Rediscovery of the Bornean bay cat. Oryx. 1994;28(1):67-70. doi:10.1017/S0030605300028313

Wearn, O. R., Bell, T. E. M., Bolitho, A., Durrant, J., Haysom, J. K., Nijhawan, S., Thorley, J., & Rowcliffe, J. M. (2022). Estimating animal density for a community of species using information obtained only from camera-traps. Methods in Ecology and Evolution, 13, 2248–2261. doi:10.1111/2041-210X.13930

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