The Iriomote Wildcat's Precarious Life in Paradise

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Recently I had the opportunity to visit Iriomote island in the far south of Japan. Located about 200 kilometers east of Taiwan, this—the second largest Island in Okinawa Prefecture ー after Okinawa Island — is a veritable treasure house of flora and fauna, including endemic and endangered species. 

Here you can find three-fifths of all the bird species in Japan. It has even been dubbed the “Galapagos of the East.” Only a slight exaggeration. 

Among the unique creatures inhabiting Iriomote are Kishinoue’s giant skink, the crested serpent eagle and the Ryukyu yellow-margined box turtle. But the most famous of these animals is undoubtedly the Iriomote wildcat, discovered in 1965. It’s a variety of feline that can be found nowhere else in the world. 

Alarmingly, the population of this indigenous mammal is estimated to have dropped to only a bit more than one hundred, and possibly is still declining. It is on the International Union for Conservation of Nature (IUCN) Red List of critically endangered wildlife. 

As one of only two native wildcats in Japan — with the other being the Tsushima leopard cat in Nagasaki Prefecture — the Iriomote cat is protected by law as a Special National Natural Monument. Nonetheless, with the number of domestic and foreign visitors to Iriomote expected to swell as the COVID-19 pandemic recedes, the survival of this endangered wild animal is far from certain. 

Japan’s Southernmost National Park

Almost all of the roughly 2,300 square kilometers of Iriomote island, other than the populated areas, has been designated as part of the Iriomote-Ishigaki National Park, the southernmost of Japan’s 34 national parks. 

Part of the park has also been named as a Protection Area for Birds and Mammals. And just this year Iriomote, along with Amami Oshima, Tokunoshima and the northern part of Okinawa Island, were collectively registered as a world natural heritage site. 

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Iriomote boasts of a unique ecology, embracing several different natural environments, such as subtropical evergreen broad-leaf forests, and the nation’s largest sprawling mangrove forest—here you can find all seven varieties of mangrove found in Japan—as well as coral reefs teeming with marine life. These diverse ecosystems of low mountains, sea and rivers are closely intertwined and, although thriving, in many ways remain fragile. 

The permanent human population of the island is not much above 2,000, divided roughly between two regions centered around the ports of Ohara in the southeast and Uehara in the northwest. 

Up until the late 19th century, settlement on Iriomote was stifled by virulent outbreaks of malaria. Then, despite the ongoing threat, for seven decades from 1889, coal mining was carried out on the island. Nonetheless, it was not until the postwar Occupation that the killer disease was finally eradicated here once and for all. 

Each of the two major hamlets lies near a river, the Nakama (17.5 kilometers long) and the Urauchi (39 kilometers long) respectively. Both can be explored by sightseeing boats or rented kayaks ー like a mini-Amazon adventure. 

Short hikes also take visitors to the Pinaisaara, Maryudu or Kanbire waterfalls. Alternatively, scuba divers can ogle some 360 varieties of coral in the warm waters offshore. 

However, since there is no airport on the island, all visitors come by high-speed ferry from Ishigaki Port, roughly one hour away. 

In Search of the Wildcat

The purpose of my journey to Iriomote was not to cruise or play with the fish in the sea, but to learn more about the Iriomote wildcat (Prionailurus bengalensis iromotensis). Therefore, I looked forward to visiting the Iriomote Island Wildlife Conservation Center run by the Ministry of the Environment. 

Much to my consternation, on arrival a local informed me that it was probably still closed due to COVID-19. I decided to chance it by taking the local bus — which only runs twice a day from Ohara to Uehara, and to the other side of the island, as far as Yubu. (Note: If you’re visiting Iriomote and have a driver’s license valid in Japan, I highly recommend that you rent a car. That is really the only feasible way to cover most of the island.)

My idea was to take the bus to the closest bus stop to Yubu Island. Then, after talking to the locals, walk back the six kilometers or so to the Iriomote Wildlife Conservation Center, spend some time there and then catch the bus heading back to Ohara later in the afternoon. 

The area between Yubu and the Center is one of the prime habitats for the Iriomote yamaneko, since it is the kind of water-rich lowland environment with many different types of prey to feed on that the cats relish. 

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Nonetheless, wildcats have also been sighted in the interior of the island, including around Mt. Dedou. Adding to the difficulty of getting an accurate count of the wildcat population is the fact that in the past locals have claimed to see another, much larger variety of cat. According to one account by a hunter, its shoulders reached roughly to the height of the man’s knees, and its fur was greenish white. 

Despite these anecdotal sightings, scientists to date have not found any evidence of the existence of this feline version of BigFoot. Could Big Paw really be lurking out there?

The Asian Leopard Cat’s Relative

It was originally thought that the Iriomote yamaneko was a separate species. But based on its morphology and genetic analysis, like its cousin on Tsushima Island in Nagasaki Prefecture it is now generally regarded as a subspecies of the Asian leopard cat, a feline that is distributed extensively on the Asian mainland. 

Both the Iriomote and Tsushima wildcats are carnivorous animals that have found a way to survive in a small island habitat by expanding their diet. The Iriomote wildcat, for example, feeds on not just its primary food sources, namely water birds and black rats, but also insects, frogs, amphibians, bats, and even baby wild pigs, fish and crustaceans. 

These wily wildcats have even learned to swim.

The Hunt

Being the only passenger on the early morning bus, I had the opportunity to chat with the bus driver. He told me that prior to the completion of Prefectural Highway 215 in 1977, which now runs around more than one-half the island, the northeast and southeast areas were essentially living in two different worlds. People wanting to travel between Ohara and Uehara, for example, would first need to catch a ferry to Ishigaki Port and then ride another ferry back to the other side of Iriomote. 

At Yubu I conversed with one of the operators of water buffalo “taxis,” each of which can ferry up to 16 tourists at a time through shallow water to Yubu Island—a four hundred meters in the distance. During the twenty minutes it takes to ford the water, the drivers entertain their passengers by playing local tunes on their sanshin (Okinawan samisen covered with snakeskin). 

The driver I spoke to confided that the water buffalo, which can weigh 750 kilograms or more, are considered “family” by their owners. 

Yubu Island is a tourist attraction. Although merely two kilometers in circumference, the entire island has become a botanical garden, with a butterfly garden, more than thirty kinds of bougainvillea, and some 40,000 coconut and palm trees.

Concerning the yamaneko, he told me: “The cats particularly like to go out onto or even lie down on the highway in the early morning. Mothers and their kittens together. We sometimes find their droppings there with hairs in them.” The wildcats are most active at dawn and dusk. 

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As I made the long walk from Yubu to the Iriomote Wildlife Conservation Center, I encountered several road signs to warn drivers that they were passing through an area where wildcats frequently appeared on the highway. In addition to imposing a 40 kilometer/hour speed limit, the authorities have also built cat underpasses, fences and specially designed ditches on the side of the road. 

Iriomote residents appear to be of two minds about the restrictions placed on development for the sake of preservation of local endangered species. The island’s unique wildlife is, of course, one of its primary tourist draws. But it limits agriculture, such as pineapple, sugar cane and rice production, as well as further development of the populated areas.

The basic problem is that the preferred habitat of the cats ー wet areas at elevations less than 200 meters above sea level ー is exactly where human activities tend to take place. 

Survival on the island has always been difficult, and in the past residents of Iriomote who were subsistence farmers have sometimes suffered from food shortages which led them to eat the wildcats in soup or other forms. In fact, they were considered a delicacy. 

The resource competition has led some conservationists to call for a halt to further migration to the island and the elimination of agriculture altogether. 

These days, the more pertinent question might be, “Can the wildcats survive the Instagram, YouTube generation?”

Trekking Through the Local Ecology

Along the highway I stumbled upon what looked like the entrance to the cross-island trekking path through the jungle. You might want to consider giving such a jaunt a try if you are particularly intrepid. 

According to one guidebook, it takes about seven to eight hours at one go, if you don’t get distracted by one of the beautiful waterfalls along the way. There are painted markers on trees, so hopefully you won’t get lost. 

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Nevertheless, although not a technically difficult hike, be advised that there are plenty of leeches, other blood-sucking insects, scorpions, three-meter-long Sakishima sujio snakes (non-poisonous) and even Sakishima habu vipers (highly poisonous) waiting to greet you in the island’s interior. 

Furthermore, a sign at the entrance to the path stated that several people need to be rescued from the interior each year, which involves considerable effort and expense. Just imagine what your medical bill would be if you don’t have health insurance valid in Japan!

If you remain committed to the adventure, your best bet might be to contact one of the local companies that offer trekking tours on the island. 

The bus driver had earlier told me that the Conservation Center had been closed to the public for sometime due to Covid. I was, therefore, delighted to find that it had opened again. Although rather small, the facility run by the Environment Ministry had an interesting array of displays on the wildcat and other local species, including some audiovisual presentations. 

The Center is staffed by researchers and university students who use radio telemetry to track the cats and operates a Roadkill Prevention Program, which includes feeding the cats delicacies like fresh rat designed to discourage them from becoming accustomed to eating roadkill. 

Nevertheless, roadkill, in the form of splattered frogs, snakes and crabs, remains an ongoing problem.

Different Features of Iriomote Wildcats

Although roughly the same size as domestic cats, the Iriomote wildcats (Prionailurus bengalensis iriomotensis), known locally as yamamayaa, differ from them in several respects. 

They have rounded ears with white spots on the back, face markings like a tiger, dusky brown or dark gray coats, short legs, relatively long bodies and fat tails. 

Adults weigh about 3.5 kilograms. Females are somewhat smaller than the males. They live mostly a solitary life within an area they have staked out as their own, which can range in size from 1.5 square kilometers to six square kilometers. There are also “wanderers”—mostly young males and older cats that have been pushed out of their chosen territory by a younger cat. 

Scientists believe that the ancestors of the Iriomote wildcats, leopard cats from the Asian mainland, arrived up to 200,000 years ago when a land bridge that disappeared perhaps 20,000 years ago still connected the island area to mainland Asia. After that their evolution diverged. 

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Threats on the Island

It should be emphasized that despite the best efforts of the authorities to stabilize the population, the Iriomote wildcat remains on the brink of extinction. 

For one thing, introduced species, especially invasive alien species, pose a big problem for the island. For example, white-lipped tree frogs (shiroago-gaeru; Polypedates leucomystax) compete with native frogs for food and territory, carry parasites, and interfere with reproduction among the indigenous frogs. 

They are not a direct threat to the cats, but cane frogs (ohikigaeru) that secrete a powerful poison would be. They have been on Okinawa Island since 1964, and reached Ishigakijima in 2015. Conservationists are desperately hoping to keep them from invading Iriomote as well. 

Other threats to the wildcats include interbreeding with domestic cats that have become feral, or the wildcats becoming accustomed to being fed by humans so that they no longer hunt. 

But by far the most immediate threat comes from traffic deaths. There have been 96 deaths from 1978 to August 2021, with a record of nine deaths being set in 2018. Due to COVID-19 travel restrictions, deaths dropped to zero in 2020, but have since rebounded.

In recent years, tourism has become one of the main industries for the island. And with it has brought new development of resorts and other facilities. In fact, in the years immediately prior to the COVID-19 pandemic, over 300,000 tourists visited the island each year. 

If the number of visitors to Iriomote who do not realize how fragile its environment is snowballs, that could further threaten the survival of the wildcats. 

At the same time, some locals are concerned that because of the huge influx of tourists, their traditional way of life may be slipping away.

Yukio Tagawa, the man who as a journalist, novelist, ecologist and writer of children’s books brought the Iriomote wildcat to the attention of the world, also did much to encourage the preservation of the cat. 

His daughter Kumi carries on the family tradition today as chair of the Tokyo-based non-profit Japan Tiger and Elephant Fund, which works to protect tigers and elephants around the world. It in turn established the Iriomote Cat Conservation Fund. A local chapter of the JTEF was established on Iriomote in 2015, which supports night patrols and other conservation activities to protect the cats.  

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Maintaining a viable balance between human activities and preservation of the natural habitat has been recognized as a problem for quite some time. Indeed, in the late 1970s, based on a report by a German scientist, the late Prince Phillip, Duke of Edinburgh wrote to then Crown Prince Akihito suggesting that all the human residents of the island be removed. 

That is not going to happen. But it has been suggested that the number of visitors to the island be limited. That is feasible, because all visitors arrive by boat. But such a proposal will no doubt face considerable opposition.

The question remains the same today: Can humans and wildcats coexist on Iriomote? 

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Author: John Carroll