- Black-footed cats (Felis nigripes) are the smallest and also one of the rarest wildcat species in Africa. They’re very reclusive, extremely hard to find, and are among the least-studied nocturnal mammals on the continent.
- Data-scarce species like the black-footed cat are difficult to conserve because the most basic knowledge — of their home ranges, territories, habitat, and reproductive, dietary and other behaviors — is often lacking. Without these many life-cycle details, the targeting of effective preservation strategies is near impossible.
- German ecologist Alexander Sliwa has made it his life’s mission to research the elusive black-footed cat. Establishing and working with a small team, he eventually led the way to the formation of the Black-footed Cat Working Group. Thanks largely to those efforts, a substantial database on Felis nigripes now exists.
- This work led to the black-footed cat being listed as vulnerable on the IUCN Red List. Though the species’ survival remains far from secure, the design and implementation of conservation strategies will no longer have to start from scratch, and can be built on valuable, already accumulated baseline data.
Every night, somewhere unseen across the vast, semidesert and dry savanna habitat of Southern Africa, the continent’s deadliest cat emerges to hunt. Black-footed cats (Felis nigripes) are ideally suited for nocturnal stalking: They are evolutionarily older than jungle cats and domestic cats, boast exceptional night vision and hearing, and are believed to kill more prey than iconic big cats like lions, leopards and tigers.
However, their most notable characteristic may have contributed to their decline. They are tiny, so receive little notice from conservationists. Full grown, they tip the scale at just 1-2 kilograms (2.2-4.4 pounds). As Africa’s smallest feline, they’re too tiny to even trigger a conventional camera trap. While the species was first described by science in 1824 (but only from skins, not a live specimen), it went largely unstudied for more than 150 years.
“Black-footed cats fly below the radar,” says zoologist Beryl Wilson, project manager for the Black-footed Cat Working Group, an NGO. Shy, secretive and very hard to find, F. nigripes remained one of the continent’s least-studied nocturnal mammals until the 1990s.
And without detailed data, determining a species’ conservation status and, more importantly, understanding how best to protect them, is near impossible. And that’s the fate that befell the black-footed cat until a sole researcher came to its rescue.
It took a die-hard researcher to study a species this small, enigmatic and mistakenly thought to be insignificant, Wilson says. You need someone, she adds, who can stick to it with “German tenacity.” For F. nigripes, that scientist is Alex Sliwa, a curator at Cologne Zoo in western Germany.
“My research on black-footed cats has guided my life for 31 years,” he says. That passion has led to the uncovering of much of what we know about the species today.
A lifetime of dedication
Sliwa’s interest in black-footed cats started young. On a trip to Berlin Zoo at age 11, he peeked into an enclosure at a small cat. It looked cartoon-like: cute, with a broad head and short legs, tiny nose and large, rounded ears. The stocky body was covered with bold, black spots and stripes — good camouflage in the dappled nocturnal shadows the species roams.
Young Sliwa was intrigued and motivated to learn more, but remembers not finding much reading material on the cats beyond a basic description like the one he could gain himself from just observing that single caged animal.
Years later, in January 1991, Sliwa — now training as an ecologist — headed to a little-known nature reserve called Benfontein, just outside Kimberley in South Africa’s Northern Cape province. He headed there to do his Ph.D. fieldwork on aardwolves (Proteles cristatus), a species of hyena. But Benfontein was also rumored to be an enclave for the elusive black-footed cat.
Sliwa’s nocturnal fieldwork placed him ideally to spot the tiny felids, and over the roughly 600 nights he spent there, he caught erratic glimpses of Africa’s smallest cat. The young researcher tried to habituate the animals to his vehicle until eventually they allowed him to follow them to their dens — mostly disused springhare burrows or hollowed-out termite mounds. These dens had earned the cats the descriptive Afrikaans nickname miershooptier — “the anthill tiger.” In 1992, he managed to take his first F. nigripes photo.
Bolstered and fascinated, Sliwa returned to Berlin to secure funding for a formal research project from cat-loving donors connected with the zoo community. Almost no research had been done on the species, and even basic facts such as its home range, territory, habitat and reproductive habits were unknown.
He knew he had to start with the very basics, he remembers, and his first big question was what did this diminutive cat eat?
‘Driving … from sunset to sunrise through a ditch’
Sliwa got his funding and went back to South Africa in 1993. He planned to fit two cats at Benfontein with radio collars. But to gather the first radio telemetry data ever on the species, he needed help, so got in touch with Wilson, then a knowledgeable zoologist at McGregor Museum in Kimberley, not far from Benfontein.
At the time, neither of them knew what such a task would entail, and it turned out to be a real baptism by fire. Following a black-footed cat in the field with a pickup truck is “like driving in first and second gear from sunset to sunrise through a ditch,” Wilson says.
The small cats can travel between 8 and 30 kilometers (5 and 19 miles) a night, zigzagging fast ahead of a research vehicle. Reputed to be harder than tracking a tiger in dense rainforest, black-footed cat fieldwork is “very intense,” Sliwa explains. You have to be focused, know what you’re doing, wear gloves and long sleeves, and expect to be bitten and scratched.
Undaunted, he did the job. In 1994, he published a paper on the diet and feeding behaviors of the black-footed cat and its extraordinary nocturnal hunting activities. He had observed the felid killing a vertebrate every 50 minutes, mostly rodents and small birds. They could devour a lark in minutes, leaving only feathers and legs behind.
The cats, the researcher learned, were able to spot birds in total darkness, and jump up to 2 meters (6 feet) to catch and kill their prey mid-air with their powerful jaws. Their sharp night vision is perfectly adapted — enhanced by a mirror-like layer behind the retina (the tapetum lucidum) that makes double use of minimal available light, a trait common to all cat species. “In relation to their body size, the black-footed cat must have one of the largest-sized eyes of all cats,” Sliwa says.
The researcher also observed the cats hunting, and repeatedly failing to catch, springbok calves (Antidorcas marsupialis). They failed every time when the calves stood up, suddenly becoming taller than the tiny cat stalking them. “It has a hell of an ego,” Sliwa says in admiration of the species’ tenacity.
Achieving conservation status
Sliwa continued publishing often and widely about F. nigripes, tremendously growing the literature and building on awareness and interest among his peers, while securing funding.
His attempts at convincing people of the work’s importance paid off. In 1995, he was approached by the Cat Specialist Group at the IUCN, the global wildlife conservation authority, to become the organization’s reference person for the species.
Thanks to the growing body of data (Sliwa himself is lead author on nearly 50 studies surveying the species), the black-footed cat went from being listed as a species of least concern (since there was no scientific backing for any other assessment result) to vulnerable on the IUCN Red List — based on its rarity and relatively restricted and patchy distribution at low densities across Southern Africa. Today, the IUCN Red List puts its estimated population at fewer than 10,000 adult individuals.
Sliwa continued traveling to South Africa and gathering data until, in 1999, now a husband and father, he decided to focus on life back in Germany. There he became the curator at Wuppertal Zoo, taking over the international studbook for black-footed cats and the European breeding program in the process.
“For a couple of years, I essentially stopped working with black-footed cats in the wild,” he says.
The captive cats presented different, unique challenges. They’re notoriously hard to breed and prone to AA amyloidosis, a disorder that leads to catastrophic kidney failure. Healthy black-footed cats don’t drink water, Wilson explains. Their kidneys are highly effective at recycling fluid in semiarid climes, but the moment even something minor goes wrong with that specialized organ, health problems cascade, she says.
In 2004, two researchers on the lookout for a solution to the captivity problem contacted Sliwa for help collecting health and epidemiological data and sperm samples from wild cats, to find out if they were disease free, and if their genes could be introduced to captive cats.
The next year, he was back in Benfontein and fitting radio collars with Wilson as part of the team. The collaboration led to the formal establishment of the Black-footed Cat Working Group in 2008. The BFCWG’s aim is to conserve the rare species by furthering awareness and conducting multidisciplinary research on its biology.
Taking the work forward
With the establishment of the BFCWG “we could keep the work going,” says project leader Sliwa. Aside from the ongoing, long-term research at Benfontein, annual captures were also conducted at two additional locations in the Upper Karoo region of Northern Cape province from 2009 to 2018, and on farmland in Grünau, Namibia (a location thought to be at the lower rainfall range of where the small cat can survive). Taken altogether, the team’s research on the black-footed cat is now the longest-running small cat project in the world — quite a distinction for an animal once almost unknown to researchers.
But today, Sliwa says he would still be more surprised to hear someone had seen a black-footed cat, rather than they hadn’t, even though the veil over their secretive lives has been largely lifted; today, an informative YouTube video details the cat’s once obscure life cycle.
Now, scientists know that the black-footed cat roams more widely than most other small cats, possibly due to the low availability of prey in their semiarid home range, combined with the large amounts they need to eat to stay warm at night. They’re solitary, only keeping company to mate or to mother kittens. These behaviors may also explain why they do badly, paired and in small enclosures, at zoos, says BFCWG program manager Wilson.
In the wild, birthing coincides with the rainy season when prey is abundant. Mothers can have two litters annually, with one to four kittens, each weighing just 60 to 88 grams (between 2 and 3 ounces) at birth.
Adult animals hunt about 70% of the night — like a cat on steroids, Wilson says. Males kill larger prey, while the smaller, more agile females are more successful in catching small birds. Overall, they mostly eat large-eared mice. In turn, they are mostly killed by predators such as black-backed jackals (Lupulella mesomelas) and caracals (Caracal caracal) or, even in the wild, die due to AA amyloidosis.
The species still keeps some secrets: Sliwa notes that the population total of 10,000 mature individuals displayed on the IUCN website is nothing more than a modeled estimate: The numbers “probably fluctuate between a couple of thousand and more,” as populations rise and fall with rainfall patterns and human impacts, he says.
A lack of connective wildlife corridors linking isolated patches of habitat can result in pockets of black-footed cats dying out after torrential rain or extreme drought. The failure of those cutoff pockets to exchange genetic material is also a serious problem, Wilson adds.
Attempts to impregnate a captive cat with “wild” sperm remain unsuccessful, but researchers are building up a collection of frozen sperm samples to protect against loss of the species’ genetic diversity.
“Contrary to the situation for most small cat species, mortalities of [wild] black-footed cats in our study areas were mostly attributed to natural causes rather than human-related causes,” Sliwa says. They mostly die because they are killed by predators or complications due to AA amyloidosis. But conserving the species in the wild is integral, he says, because creating a long-term sustainable population in captivity has so far not been possible. Zoos are frustrated with black-footed cats, Sliwa says, because they have no handle on the disease issue. A pair might breed once or twice, then die with their offspring due to it.
It is impossible to provide a prognosis for the species’ survival: “Nobody knows,” Sliwa says. Global warming, new diseases or more intensive use or other impacts on their rangelands are only some of the factors that can cause the species to “slip quietly into extinction.” Despite more media attention, including a feature by the BBC, people are still not very aware of the small cat, he says, and funding to continue the research is a constant battle — as is the case with most small wildcat species.
Would it make a difference if black-footed cats disappeared overnight? Economically and even ecologically, probably not, Wilson says. “Except, their presence indicates a healthy environment, for which we as humans are the custodians.”
For zoo curator Sliwa — sitting amid photos of lemurs and lions, and surrounded by towering piles of paperwork awaiting attention — there’s much more to do: Data, he says, are needed on the survival of black-footed cat kittens, on subadults and their dispersal, on scent marking, and there are also theses projects to supervise.
For him, the black-footed cat is a lifelong commitment. “I will continue,” he says, “until I can’t do it any longer.”
Banner image: Despite more research attention, the rare black-footed cat’s future remains uncertain. Image by Alex Sliwa.
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Citations:
Sliwa, A. 1994. Diet and feeding behaviour of the Black-footed Cat (Felis nigripes Burchell, 1824) in the Kimberley Region, South Africa. Der Zoologische Garten N.F. 64: 83–96.
For a list of studies by A. Sliwa, his team members, and other researchers, see the Library section of the BFCWG website.
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