Overview

Distribution

Prionailurus iriomotensis is endemic only to Iriomote Island, the southernmost isle in the Ryukyu Archipelago, Japan. The island is approximately 284 km^2.

Biogeographic Regions: palearctic (Native )

Other Geographic Terms: island endemic

  • IUCN Cat Specialist Group - The World Conservation Union. 1996. "Iriomote cat" (On-line). Accessed October 09, 2002 at http://lynx.uio.no/catfolk/sp-accts.htm.
  • International Society for Endangered Cats Canada (ISEC Canada). 2001. "Iriomote cat" (On-line ). Accessed 10/09/02 at http://www.wildcatconservation.org/cats/factsheets/asia/iriomote/index.shtml.
  • Okamura, M., T. Doi, N. Sakaguchi, M. Izawa. 2000. Annual Reproductive Cycle of the Iriomote cat *Felis iriomotensis*. Mammal Study, 25(2): 75-85.
  • Yasuma, S. 1988. Iriomote Cat: King of the Night. Animal Kingdom, 91(6): 12-21.
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Historic Range:
Japan (Iriomote Island, Ryukyu Islands)

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Physical Description

Morphology

The fur of P. iriomotensis is dark brown and of medium length. Dark spots occur in rows along the body, and dark stripes are prevalent along the neck. The posterior surface of the ears of Iriomote cats are marked by white spots. Ther is a characteristic white area surrounding the eyes. The irises vary from yellowish-gold to amber.

The body shape of this species is somewhat elongated. The legs are relatively short, as is the tail, giving these animals a "low-slung" appearance. The average length is between 70 and 90 cm. Weight for males averages 4.2 ± 0.5 kg (n=15) and for females 3.2 ± 0.3 kg (n=10).

Range mass: 3.2 to 4.2 kg.

Average length: 70-90 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes alike

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Ecology

Habitat

The island of Iriomote consists mainly of lowland mountains. The highest point on the island is 469 m on Mt. Komidake. Cover is composed of broad-leaved, evergreen, and sub-tropical primary forest over a majority of the mountainous regions. Mangrove forests are common among the estuaries. Cleared areas along with cultivated fields are found in the area of coastal flats. Iriomote cats range throughout the mountains and forested areas, and sometimes appears along the coastal beaches and villages.

Range elevation: 0 to 469 m.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: forest ; rainforest ; mountains

Other Habitat Features: agricultural ; estuarine

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Habitat and Ecology

Systems
  • Terrestrial
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Trophic Strategy

Prionailurus iriomotensis is opportunistic, and will feed on almost all the animals that can be found on the island. Their diet includes small mammals (such as fruit bats and rats); birds, snakes, frogs, lizards, insects and occasionally fish and crabs. After a kill, Iriomote cats have been observed to temporarily abandon the kill, but are speculated to occupy the general vicinity during the vacated time.

Animal Foods: birds; mammals; amphibians; reptiles; fish; insects; aquatic crustaceans

Primary Diet: carnivore (Eats terrestrial vertebrates)

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Associations

Iriomote cats are key predators in the island ecosystem preying on a variety of organisms. Though the cats are efficient predators, the impact on the community is minimal due to their small population size.

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There are no documented predators or Iriomote cats.

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Known prey organisms

Prionailurus iriomotensis preys on:
non-insect arthropods
Actinopterygii
Crustacea
Insecta
Amphibia
Reptilia
Aves
Mammalia

This list may not be complete but is based on published studies.
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Life History and Behavior

Behavior

Iriomote cats rarely vocalize, but during the breeding season they can be heard. Mating sounds are similar to domestic cats. Thi species is also reported to make low murmuring "bow-wow" sounds when fighting. Scent marking is integral in intra-specific communication relaying information on territory and sexual receptiveness. Tactile communication is undoubtedly important between a mother and her kittens, between mates, and between competitors in aggonistic circumstances.

Communication Channels: visual ; tactile ; acoustic ; chemical

Other Communication Modes: pheromones ; scent marks

Perception Channels: visual ; tactile ; acoustic ; chemical

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Life Expectancy

Information about life span is predicated upon comparisons to leopard cats (P. bengalensis) due to the lack of longevity studies on P. iriomotensis in the wild or in captivity.

Leopard cats can live up to 15 years, but tooth loss generally occurs between the ages of 8 to 10 years. It is likely that Iriomote cats are similar.

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Reproduction

Very little is known about the mating habits of P. iriomotensis. In one study, only six of 686 reported chance observations of Iriomote cats resulted in pair sightings. However rare, these sightings all occurred between December and March, indicative of the presumed breeding season, and suggesting a monogamous breeding system. A male and female exhibiting "courtship behavior" were observed in the month of January. Marking frequency in males showed a peak through the months of February to April. Marking through urine is presumed to increase in response to the breeding season. The male of captive pair was also observed to increase marking frequency during breeding activity.

Mating System: monogamous

The breeding season seems to occur primarily from winter to spring but may not be seasonally restricted. Most mating likely proceeds from February to March, based on the distribution of birth months from April to July. There was a clear peak in births for the month of May. Gestation is estimated at 60 days based on observations of leopard cats (Prionailurus bengalensis).

Litters most commonly have a single kitten. However, twins have been reported. In one study the majority of kittens observed were single and out of 41 chance observations of mothers and offspring, only four produced twins. One source states that there have been no documented reports of Iriomote cats having a litter size exceeding two.

The mother nurses her offspring until they are abouttwo to three months old. Even after weaning, maternal care continues until the kittens are 4 to 4.5 months of age. Animals reach sexual maturity around the age of 8 months.

Breeding interval: Iriomote cats generally breed once per year.

Breeding season: Breeding is presumed to occur between February and March.

Range number of offspring: 1 to 2.

Average number of offspring: 1.

Average gestation period: 60 days.

Range weaning age: 60 to 90 days.

Range time to independence: 4 to 4.5 months.

Range age at sexual or reproductive maturity (female): 8 (low) months.

Range age at sexual or reproductive maturity (male): 8 (low) months.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous

In P. iriomoensis, as in most mammals, all aspects of parental care, including food procurement, protection, adequate resources, and teaching, are provided solely by the female. As the altricial kittens develop in a den of some type, the mother provides them with milk, protection, and grooming. After the kittens are able to follow the mother, they must be taught to hunt for themselves. The mother appers to do this alone, as well.

Territory has been observed to be shared between mothers and daughters up to 6.5 months of age, inidcating a post-independence association between mothers and their female offspring. Weaning occurs from 2 to 3 months of age, and independence is established from 4 to 4.5 months of age.

Parental Investment: no parental involvement; altricial ; pre-fertilization (Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female); post-independence association with parents; extended period of juvenile learning; inherits maternal/paternal territory

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Conservation

Conservation Status

Prionailurus iriomotensis is considered highly endangered. It is the world's most vulnerable and rarest felid species, based on the minute range and small population size. The population is estimated to be less than 100 individuals.

Prionailurus iriomotensis is placed under CITES Appendix II, and has been fully protected since 1967. Habitat destruction is the prominent threat.

US Federal List: endangered

CITES: appendix ii

IUCN Red List of Threatened Species: critically endangered

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IUCN Red List Assessment


Red List Category
CR
Critically Endangered

Red List Criteria
C2a(ii)

Version
3.1

Year Assessed
2008

Assessor/s
Izawa, M.

Reviewer/s
Nowell, K., Breitenmoser-Wursten, C., Breitenmoser, U. (Cat Red List Authority) & Schipper, J. (Global Mammal Assessment Team)

Contributor/s

Justification
Found only on small (284 km²) Japanese island of Iriomote, which consists predominantly of low mountains (300-460 m) with sub-tropical evergreen forest, including extensive belts of mangrove along the waterways. However, studies have shown Iriomote cats to prefer lower elevations, a mosaic of wetland, streams, small hills - which are also where the human settlements are (Izawa et al. 2002). Home range sizes have ranged from 1.4-5.8 km² (Schmidt et al. 2003). The population was estimated at around 100 (99-110) individuals in 1994. While the population was considered stable since monitoring began in 1982 (Izawa et al. 2002), researchers now think the population is declining due to accelerated rates of lowland habitat loss over the past decade, and are working to estimate the level of decrease (M. Izawa pers. comm. May 2008). Listed as Endangered on Japan's 2002 national Red List (Izawa et al. 2007), concern over a decreasing population trend warrants listing of the Iriomote Cat on the IUCN Red List as Critically Endangered, as the population size is fewer than 250, is declining, and consists of a single subpopulation.

History
  • 1996
    Endangered
  • 1996
    Endangered
  • 1994
    Endangered
    (Groombridge 1994)
  • 1990
    Endangered
    (IUCN 1990)
  • 1988
    Endangered
    (IUCN Conservation Monitoring Centre 1988)
  • 1986
    Endangered
    (IUCN Conservation Monitoring Centre 1986)
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Current Listing Status Summary

Status: Endangered
Date Listed: 07/27/1979
Lead Region: Foreign (Region 10) 
Where Listed: Entire


Population detail:

Population location: Entire
Listing status: E

For most current information and documents related to the conservation status and management of Prionailurus iriomotensis, see its USFWS Species Profile

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Population

Population Trend
Decreasing
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Management

Conservation Actions

Conservation Actions
Listed on CITES Appendix II (as Prionailurus iriomotensis).
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Relevance to Humans and Ecosystems

Benefits

Some locals view this species as an obstruction to economic development. There have been proposals to conserve lowland habitat for these cats, but since such areas are potentially important agricultural areas, there is a direct conflict between the cats and the humans on the island.

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Iriomote cats are charismatic, and are becoming a major source of tourist appeal. This brings in economic revenue.

Positive Impacts: ecotourism

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Wikipedia

Iriomote cat

The Iriomote cat (Prionailurus bengalensis iriomotensis) is a subspecies of the leopard cat living exclusively on the Japanese island of Iriomote. It has been classified as Critically Endangered by IUCN since 2008, as the population size is fewer than 250, is declining, and consists of a single subpopulation.[1] As of 2007, there are an estimated 100–109 individuals remaining.[2]

In Japanese it is called Iriomote-yamaneko (西表山猫?, "Iriomote mountain cat"). In local dialects of the Yaeyama language, it is known as yamamayaa (ヤママヤー?, "the cat in the mountain"), yamapikaryaa (ヤマピカリャー?, "that which shines on the mountain"), and meepisukaryaa (メーピスカリャー?, "that which has flashing eyes").[3][4]

Characteristics[edit]

A taxidermied Iriomote cat at the Iriomote Wildlife Conservation Center. It has dark gray and brown fur, rounded ears, light amber eyes, and a flattened nose.

The fur of the Iriomote cat is mostly dark gray and light brown, with lighter hair on the belly and insides of the limbs. Hair along the jaw is white.[5] On each cheek are two dark brown spots. There are 5–7 stripes spanning from the forehead to the back of the head, but unlike the leopard cat the stripes stop before reaching the shoulders.[6][7][5] Dark brown spots cover the sides of the body, and there are 3–4 bands of irregular stripes on the chest.[8][7] The tail is dark brown; darker spots pattern the back side of the tail while the underside of the tail is solid. The tip of the tail is dark.[5]

The tips of the ears are rounded, with black hair along the edge. There are no tufts of longer hair on the top of the ears. Adult Iriomote cats have a white spot on the back of each ear, much like those found on tigers' ears.[5] Young Iriomote cats do not have these marks, and even as adults the spots will not be as white as those seen on other leopard cat subspecies.[5]

The Iriomote cat's eyes are a light amber color.[5] Its nose is large and flat, with no fur covering the reddish-brown skin.[8][7][5] The paw ranges from 29–37 mm (1.1–1.5 in) wide, in contrast to the 24–30 mm (0.94–1.18 in) wide paw of a domestic cat.[5]

The skull is longer and more narrow than of a domestic cat. When compared to the leopard cat's skull, the Iriomote cat's is roughly the same size but thicker. Because of this, the Iriomote cat's brain is smaller; a male leopard cat's brain is about 42 grams whereas a male Iriomote cat's brain is about 30 grams.[5] The occipital bone of the skull and the auditory capsule are not connected.[6][8] The mandibular symphysis is short.[6][7]

Male Iriomote cats grow to be 50–60 cm (20–24 in) long and weigh 3.5–5 kg (7.7–11.0 lb). Females are smaller at about 50–55 cm (20–22 in) long and 3–3.5 kg (6.6–7.7 lb).[9] Their tails are thick from base to tip and 23–24 cm (9.1–9.4 in) long.[7][5] They have long torsos and short, thick limbs.[5] Their necks are also thick, and their shoulders are muscular, though their jumping power is comparatively weak. Unlike other small cats, their spines cannot bend sharply.[5]

The Iriomote cat has six pairs of incisors, two pairs of canine teeth, four pairs of premolars, and two pairs of molars for a total of 28 teeth. Compared to other cats, including small wild cats, the Iriomote cat is lacking one pair of premolars on the top jaw behind the canines.[5] In addition to this, unlike most other subtropical mammals, Iriomote cats' teeth give details about their year-to-year history. It is expected that these details will help determine age and behavior of the cats.[10]

The anal scent glands of the Iriomote cat surround the anus, which contrasts with other cat species' which are inside the anus.[5][11]

Distribution[edit]

The Iriomote cat is indigenous to the Japanese island of Iriomote, which spans about 290 km2 (110 sq mi).[6][8][7][12][13][9][14][15] Iriomote consists predominantly of low mountains ranging 300–460 m (980–1,510 ft) in elevation with sub-tropical evergreen forest, including extensive belts of mangrove along the waterways.[16] It is the smallest habitat of any wild cat species in the world.[17]

The cats are predominantly found in the subtropical forests that cover the island, no higher than 200 m (660 ft) above sea level,[6][15][18] and prefer areas near rivers, forest edges, and places with low humidity.[6][7][9]

Ecology and behavior[edit]

Iriomote cats are terrestrial, but climb trees, go into the water and also swim.[6][15][18] They are nocturnal and especially active during twilight hours.[8][14] During the daytime, they sleep in tree hollows or in caves. They mark their territory by urinating and defecating on rocks, tree stumps and bushes. Their home ranges vary from 1 to 7 km2 (0.39 to 2.70 sq mi) big.[6][7][9]

Home range[edit]

Iriomote cats are usually solitary. Their home range varies seasonally and also individually, and is smaller during the mating season. In 1998 and 1999, a male and a female Iriomote cat were radio tracked for seven to 13 successive days in the western part of the island. Their home ranges overlapped extensively in all periods. The periodical home range of the male was 0.83–1.65 km2 (0.32–0.64 sq mi) in size, and the resident female's range was 0.76–1.84 km2 (0.29–0.71 sq mi).[14][19][20]

Iriomote cats are territorial.[19] Home ranges of males and females overlap, and one to two females live within a male's home range.[19][21] Typically, home ranges of same gender cats will not overlap, but partial overlaps are seen.[19][21][22] Often, these small overlaps are hunting grounds.[22] It is thought that they patrol their territories during three to four days, marking and hunting as they go.[19]

Young male Iriomote cats and some adult cats are transient, i. e. wandering over the island and waiting for an open home range slot that they can occupy by marking this area.[21][22] Female cats allow their young to stay in their own home range and mark a new territory once the next breeding season comes.[6][7]

Feeding ecology[edit]

Slaty-legged crakes make up a portion of Iriomote cats' diet

Iriomote cats are carnivorous and prey on various mammals, birds, reptiles, amphibians, fish, and crustaceans. They typically ingest 400–600 g (0.88–1.32 lb) of food a day.[18] Other wild cats primarily hunt small mammals such as rodents and rabbits, but because there are no other carnivores to compete with the Iriomote cat on the island, there is no need for them to isolate themselves from the various habitats and food sources that are available. Thus, their diet is quite varied.[22]

Mammalian prey includes black rats, Ryukyu flying fox and young Ryukyu wild boar. Their prey also includes a wide range of birds such as the spot-billed duck, slaty-legged crake, Eurasian scops-owl, pale thrush, and white-breasted waterhen.[6][8][9][14] Reptiles include various types of snakes and Kishinoue's giant skink.[6][8][9][14][23] They are also known to hunt Sakishima rice frogs, yellow-spotted crickets and crabs.[6][8][9][14] As their hunting grounds tend to be in swamps or on shores, they sometimes swim and dive to catch water birds, fish, and freshwater prawns.[18][22]

When eating birds that are larger than a dusky thrush, most types of cats will pluck the feathers and then eat it, but the Iriomote cat will eat even large birds whole without removing the feathers.[18] Also unlike other cats, the Iriomote cat does not kill its prey immediately by breaking the spinal cord. Instead it holds the animal in its mouth until it stops moving.[6]

It is estimated that water birds comprise about 60% of the cat's diet with black rats being its secondary source of food at about 10–30% of its diet.[19] Based on stool samples, birds represent 60% of their diet, black rats 30%, insects 30%, lizards and frogs about 15–20%, bats 3–17%, and wild pig less than 1%. In addition, fish and crustaceans appear roughly 3–4% of the time.[19][19][24]

Seasonal dietary changes have been observed. They eat rats and frogs year-round, lizards in the summer and spring, and crickets and bats more often in fall and winter.[22]

Reproductive behavior[edit]

During the mating season, Iriomote cats become active during the day as well.[11] Breeding females are more active than nonbreeding ones during the late night and morning hours.[25] Outside the mating season the cats live in solitary, but when they begin breeding they act together.[11][19] The mating season lasts from December to March, and females go into heat several times during this period, with the peak being in January and February.[9][19][25] Towards the end of February, they fast for about two weeks. It is during this period that females are most sexually excited. Male and female cats always stay together at this time, and it is thought that conception happens during these two weeks.[11]

Pregnancy is viviparous, and between April and June pregnant female cats give birth to 1–3 kittens in a tree hollow or cavern.[11][21] The locations chosen for birthing and rearing are dry and have good ventilation.[11] Kittens stay with their mother for about eleven months.[11] They begin to become more independent during the fall and winter months. They stay in their mother's home range from anywhere between a few months and years.[22] Kittens reach maturity twenty months after birth.[7]

Lifespan[edit]

It is estimated that Iriomote cats live for seven to eight years in the wild, and eight to nine years in captivity.[7][11] Human influences, traffic accidents and traps may lower their lifespan to two to five years.[11] In captivity, an Iriomote cat lived for an estimated 15 years and one month, the longest known lifespan of any Iriomote cat.[26]

Discovery[edit]

The Iriomote cat was discovered in 1965 by Yukio Togawa (戸川幸夫 Togawa Yukio?), an author who specialized in works about animals. In 1967, it was first described by Yoshinori Imaizumi, director of the zoological department of the National Museum of Nature and Science in Tokyo.[27]

Prior to its scientific discovery, the Iriomote cat was known locally by various names: yamamayaa (ヤママヤー?, "the cat in the mountain"), yamapikaryaa (ヤマピカリャー?, "that which shines on the mountain"). To distinguish between the Iriomote cat and other cats on the island, locals also gave other cat nicknames such as pingimaya (ピンギマヤ?) for stray cats and maya (マヤ?) or mayagwaa (マヤグヮー?) for house cats.[28][28][29] Others, however, believed that the Iriomote cats was a feral cat.[6][8]

Prior to specimen acquisition[edit]

Based on information from the locals, Tetsuo Koura (高良鉄夫 Koura Tetsuo) from the University of the Ryukyus was able to capture a kitten in 1962, but did not get an adult specimen.[6] In 1964, Tokio Takano (高野凱夫 Takano Tokio) from the exploration department of Waseda University informed Imaizumi of the rumors of a cat living in the mountains of Iriomote.[5]

In February 1965 Togawa visited the Yaeyama Islands. He had heard in Naha from a newspaper columnist that there were rumors of wild cats living on Iriomote.[29] He at first assumed that, like reports of the extinct Japanese wolf, people must have been mistaking escaped and feral house pets for wild animals. He spoke with colleague Tetsuo Koura who knew of and believed there to be some truth to the rumors. Koura then entrusted Togawa with the task of acquiring evidence.[5][29] Togawa then traveled to Iriomote to gather information for his own report and to collect information on the Iriomote cat and a specimen.[29]

Upon arriving on the island, Togawa learned that because there wasn't enough food on Iriomote, people would cook Iriomote cats that had been caught and use the meat in soup. Cats caught in traps would also be disposed of, which made acquiring samples difficult.[29]

Following these discoveries, he went to the hamlet of Amitori (網取部落 Amitori Buraku) on the western side of the island. There, a middle school teacher who had worked under Koura said that he had caught one of the cats in a trap set for wild boar. He had sent the skin to Koura but buried the rest of the body. Togawa dug up the remains and got the skull. He also found two feces samples near the village, and was able to get a skin from a fisherman who lived in Inaba (イナバ部落 Inaba Buraku), a hamlet along Urauchi River.[29]

He returned to Koura and sent the two skins, the feces, and the skull to Yoshinori Imaizumi at the National Museum of Nature and Science where the The Mammalogical Society of Japan (日本哺乳動物学会 Nihon Honyū Dōbutsu Gakkai) tested the subjects.[29] The analysis took place on March 14, 1965.[5] The results showed the cat to be either a new species or a new subspecies, but there weren't enough samples to confirm. They requested either a complete set of remains or a live specimen.[5] Following the announcement, some members of the society believed the samples to show simple mutations while others believed them to be the remains of wild cats that had previously been brought to and left on the island by foreign ships.[29]

Live specimen acquisition to announcement[edit]

In June 1965, Togawa returned to Iriomote with Koura in order to obtain a complete set of remains, a live specimen, and information regarding the cat's ecology. They brought box traps and silvervine to aid their efforts in catching a live cat. According to hunters, though, only one or two cats per year were caught, and the number of remaining cats was probably quite low. Togawa did not expect to catch one alive.[30]

Maaree Waterfall, where a group of children found an Iriomote cat on May 5, 1965

In May 1965, prior to Togawa's return to the island, a group of children from Ōhara Elementary School (大原小学校) on a field trip to the southern part of the island found a weakened, injured male Iriomote cat at the base of the small Maaree Waterfall (マーレー滝 Maaree Taki) on Haemita Beach (南風見田の浜 Haemita no Hama). The teacher in charge of the children took the cat. Another teacher preserved the pelt in formalin and buried the skeleton in a wooden box behind the school. Togawa exhumed the remains, and this cat became the prototype for the species.[5][30] In addition to this example, the scientists also were able to obtain the crushed skull of a kitten from the neighboring Yubu Island that was later reconstructed by Imaizumi.[30]

In addition to researching the Iriomote cat, Togawa also looked into rumors of a larger cat on the island (see #Yamapikaryaa) and conducted an investigation.[30] Before returning to Tokyo, he offered $100 for any live Iriomote cat and $30 for dead cats that were brought to him. With the aid of the Taketomi mayor and the Daily Yaeyama Newspaper (八重山毎日新聞 Yaeyama Mainichi Shinbun), he was able to publicize the offer on bulletin boards and in other ways.[31] He also announced rewards for the rumored large cat on the island: $200 if brought in alive, $100 for remains.[31]

Through these offers, he acquired two complete skeletons, two skulls, and three pelts that he brought back with him to Tokyo. One of the pelts was that which the elementary school children helped obtain, and it was confirmed to be that of an Iriomote cat. The sample from Yubu Island was small, and judgment was held back. A sample from Ishigaki Island was discovered to be a house cat.[31]

In January 1966, the body of an Iriomote cat that had been caught in a wild boar trap in the mid-basin of the Nakama River was sent to Koura at the University of the Ryukyus, but there was no more information regarding captures for some time after this.[31] In December 1966, Hiroshi Kuroda (黒田宏 Kuroda Hiroshi), a hunter at the Nakama River's mid-basin, caught a live male cat, but it escaped immediately.[31] He then caught another male cat soon after.[5]

On January 15, 1966, local hunters caught a young female Iriomote cat near Nakama Mountain (仲間山 Nakama-yama).[5][31] The National Museum of Nature and Science planned on using funds intended for garden repairs to pay for the specimens, but the hunters who caught the cats expected $1000–$3000 per cat.[31] At the persuasion of the director of the District Forestry Office, the hunters accepted an award within the budget as a “daily allowance” or “finder's fee”.[31]

During this time, the mayor of Taketomi was making negotiations with the Southern Japan Liaison Offices (南方連絡事務所 Nanpō Renraku Jimusho) and the Ryukyu government. He traveled to Naha for these discussions, which covered the possibility of offering the two captured Iriomote cats to the emperor with the stated purpose of increasing national knowledge about Iriomote and for the promotion of industrial development on the island. At the same time, the Taketomi town offices, under the premise of obtaining permission from the Ryukyu government to keep the cats, confiscated samples from the staff of the National Museum of Nature and Science and brought them back to their offices.[31]

With Togawa pressuring the newspapers and Yoshinori Imaizumi urging the Ryukyuan government and Southern Japan Liaison Offices through the Ministry of Education, the Southern Japan Liaison Offices denied the possibility of giving the cats to the emperor, and the Ryukyuan government persuaded the mayor not to follow through with his plans. Finally, the specimens were delivered to the museum.[31]

The cats arrived at Haneda airport in March 1967.[31] Yoshinori Imaizumi kept them shortly until Togawa, having been entrusted by the museum to observe them, took charge of them for about two years.[5][32] The cats were then transferred to the museum for monitoring. The male died on April 25, 1973 and the female on December 13, 1975. The male's pelt was temporarily stuffed, the blood was sent off for chromosomal research, and the rest of the body was preserved in formaldehyde. The female was stuffed and put on display in the museum.[5]

In May 1967, The Mammalogical Society of Japan issued their third and fourth issues, announcing in English the discovery of a new genus of cat that was closely related to the primitive Metailurus genus of cats.[5] The former genus name of Mayailurus stems from the word used for “cat” on Iriomote, maya-, while -ailurus comes ancient Greek and also means “cat”.[5] The subspecies name of iriomotensis means “from Iriomote”.[5] The Japanese name of Togawa mountain cat (トガワヤマネコ Togawa-yamaneko) was proposed by Yoshinori Imaizumi, in honor of Togawa who discovered the species, but Togawa turned down the request and instead supported the name Iriomote cat (イリオモテヤマネコ Iriomote-yamaneko) based on the Tsushima cat, which was also named after the location at which it was discovered. Koura agreed with Togawa, thus officiating the name.[29]

Classification and genealogy[edit]

In 1967, Dr. Yoshinori Imaizumi (今泉吉典 Imaizumi Yoshinori) announced the Iriomote cat to the scientific community as a new species of feline in its own genus. It was labeled Mayailurus iriomotensis.[13] Dr. Imaizumi pointed out that compared to other leopard cats, the Iriomote cat retained some especially primitive features. Judging from these characteristics, Yoshinori Imaizumi estimated that the Iriomote cat appeared as a species sometime between ten million years ago in the Miocene epoch and three million years ago during the Pliocene epoch. He also believed that they shared many primitive characteristics with fossils in the extinct Metailurus genus.[13] He emphasized these points, stating that the Iriomote cat and Metailurus shared a common ancestor sometime between ten million and five million years ago,[13][5] and from that he deducted that the Iriomote cat's ancestors must have widened its range from mainland Asia to Iriomote and other areas beginning three million years ago.[13] It appears to be a very ancient species, a ‘missing link’, nearer to the common root of the cat tribe than any other extant species.[33]

In contrast to Dr. Imaizumi's assertions about its unique characteristics, other researchers have strongly refuted the idea that the Iriomote cat is its own species ever since its discovery. Investigations involving skulls and teeth, samples and living animals, and genetic research were conducted to determine whether it is its own species or a subspecies of leopard cat.[6][13] Because of these studies, it has been subordinated under the genus Prionailurus as Prionailurus iriomotensis.[34]

The Iriomote cat's karyotype, the restriction fragment length of the ribosomal RNA (rRNA), and molecular phylogenetic analyses of the mitochondrial 12S rRNA and cytochrome b have proven to be identical, or nearly so, to the leopard cat's.[13][35] The two cats are assumed to be extremely closely related, their differences being categorized as either intraspecies variations or individual mutations. Also, from the speed of cytochrome b's base-pair substitution and its diversity, it is estimated that the Iriomote cat diverged from the leopard cat around 180,000-200,000 years ago.[36] According to marine geologists, the Ryukyu Islands were connected to mainland Asia via a land bridge from about 20,000 years ago to 240,000 years ago. Scientists believe that the Iriomote cat moved its range to the islands during this period.[13] Because of this, it is assumed that there is little genetic variety within the species.[14][37]

Threats[edit]

Sign warning motorists of animals, with a picture of an Iriomote cat

Destruction of habitat due to development, predation by dogs, traffic accidents, and traps set for wild boar and crabs all contribute to the decline in number of Iriomote cats.[6][7][9] During the second survey of the island, conducted from 1982–1984, it was estimated that 83–108 Iriomote cats lived on the island. The third survey, conducted from 1993–1994, estimated that 99–110 of the cats were on the island. During the fourth survey, conducted from 2005–2007, there were an estimated 100–109 remaining cats.[2][14] The method of estimating the numbers differed between the third and fourth surveys, though; if the third estimate were to be revised, there would have been an estimated 108–118 Iriomote cats at the time, meaning that the population is shrinking over time.[2]

Along with the traffic accidents, logging due to development, and development of the swamplands, house pets are also causing problems. House cats and stray cats especially cause issues with competition, disease transmission, and genetic pollution due to hybrids born of inter-species breeding. It is also feared that dogs prey on the Iriomote cats.[9][14]

Iriomote Wildlife Conservation Center

The primary fear stems from house cats that have become feral or partially feral, but monitoring of these interactions have not been made. Pressure from competition over food, contact with house cats that have contracted feline immunodeficiency virus (FIV) and other contagious diseases, as well as decrease in population due to hybridization are all important issues with the Iriomote cat.[9]

In June 1999, the Iriomote Wildlife Protection Center conducted an investigation among 50 house and feral cats and 23 Iriomote cats in order to see if FIV was being transmitted within the populations. FIV was not seen in any of the Iriomote cats, but three of the house and feral cats tested positive.[38] Because of the fears regarding transmission of the disease, starting in 2001 Taketomi Town enacted the Cat Breeding Ordinance which required all residents to register their pet cats. In June 2008, the ordinance was revised to include mandatory FIV testing and vaccinations, spaying and neutering, and microchipping. A new limit to the number of pets allowed per owner was also added.[39]

Furthermore the cane toad, which secretes a poisonous liquid from glands in its ears, has also appeared on the island. In order to prevent further contamination of Iriomote, residents of Ishigaki Island began extermination measures in 2008.[40][41]

Conservation[edit]

Status[edit]

Since 2008, the Iriomote cat is categorized as "Critically Endangered" by IUCN.[1]

The Iriomote cat has been designated a natural monument by the Okinawa government.[31] On May 15, 1972, along with the recovery of Okinawa, it was nationally recognized as a natural monument. On March 15, 1977, it was given special status amongst natural monuments, and in 1994 with the Species Protection Act, it was designated as a Specified National Endangered Species of Wild Fauna and Flora (国内希少野生動植物種 Kokunai Kishō Yasei Dōshokubutsu-shu).[12][14][42] This act was adopted on January 28 and enacted on March 1.[43]

Projects and activities[edit]

In 1977, Prince Philip, Duke of Edinburgh wrote a letter addressed to Crown Prince Akihito regarding the preservation of the Iriomote cat. The report attached to the letter (written by Professor Leyhausen) suggested outlawing any further migration to the island as well as banning the cultivation of the land.[11] In response, Crown Prince Akihito said that he wished for a way that would allow for the preservation of the cats and the continued habitation of people on the island. He also explained that the prime minister at the time, Takeo Fukuda, was considering the implementation of a wildlife sanctuary on Iriomote.[11]

Sign warning motorists of Iriomote cats. The number is used in reporting sightings of the cat.

In 1972, the National Museum of Nature and Science prepared for researching the ecology of Iriomote cats, and in November 1973 the World Wide Fund for Nature and the Ministry of the Environment conducted a joint preliminary investigation regarding the cat's ecology,[2][5] and from 1974 the Ministry of the Environment conducted a comprehensive investigation that lasted three years. After that, there were three more investigations beginning in 1982, 1992, and 2005.[2]

In 1979 the EPA began a three-year-long feeding operation in order to increase the survival rate of kittens,[11] but these actions have received some criticism.[7]

Since the Iriomote cat's discovery, various investigations have taken place. In 2006, automatic cameras and radio telemetry were used in order to understand the cats' state of life. Pathological tests regarding the contagiousness of diseases were also conducted, and tests on feces and food leftovers were also done. They also compiled records of cat sightings by locals and tourists.[22]

Part of the Iriomote's cat range was designated as Iriomote Ryukyu Government Park (西表政府立公園 Iriomote Seifu Kōen) on April 18, 1972. With the US's return of the Ryukyu Islands to Japanese control on May 15, it became Iriomote National Park, and in March 1991 11,584.67 hectares of the island was designated the Iriomote Forest and Ecological Preserve (西表島森林生態系保護地域 Iriomote-jima Shinrin Seitaikei Hogo Chiiki) in order to protect the natural environment within the area's confines.[44][45] Despite these efforts, not enough land within the cats' preferred habitat of 200 meters below sea level was included. In 1995 the Iriomote Wildlife Preservation Center (西表野生生物保護センター Iriomote Yaseisei Seibutsu Hogo Sentā) was established to increase preservation work, enforce research, and to increase understanding of the cats.[14]

"Zebra zone" strips and inclined ditches on an Iriomote road

Since the US returned control of the Ryukyu Islands to Japan in 1972, development on Iriomote continued with finances from the Okinawan mainland. In 1977 a prefectural road was built that circles half of the island, which has led to a few Iriomote cat deaths every year caused by traffic accidents.[11] The Ministry of the Environment as well as the governments of Okinawa and Taketomi Town began installing road signs to warn people of Iriomote cats, tunnels beneath the road for animals' safe crossing, zebra zones which create loud noises when cars ride over them, wide ditches on the sides of roads, and ditches on the side of the road that are inclined on one side in order to improve the preservation of the cats.[14][46] However, many residents have objected to restrictions on land cultivation and improvement brought about by the measures in place to protect the Iriomote cat and other species on the island.[11]

In captivity[edit]

There have been a handful of Iriomote cats kept in captivity. A five-week-old male kitten that had been separated from its mother was found on June 14, 1979. He was named Keita and was kept at the Okinawa Zoo until he died of old age at approximately thirteen years and two months of age.[11] A female specimen was also kept at the National Museum of Nature and Science. She was believed to have been approximately nine years and seven months old when she died.[11] On August 6, 1996, a male kitten that would later be known as Yon was taken into care at the Iriomote Wildlife Protection Center after being involved in a traffic accident.[26]

Yon[edit]

Discovery and hospitalization[edit]

The taxidermied body of "Yon". He was hit by a car on August 6, 1996 then rehabilitated at the Iriomote Wildlife Conservation Center. He died on April 9, 2011 at the estimated age of fifteen years and one month, the longest confirmed lifespan of any Iriomote cat.[26]

On August 6, 1996, a young Iriomote cat was involved in a traffic accident near Nadara Bridge on the northern part of the island. He weighed 1.6 kilograms and was assumed to have been born in early March, making him about five months old. It is possible that he had just been separated from his mother. The next morning he had regained consciousness, but he wasn't able to regulate his body temperature due to the serious injuries he received. He was transferred to Ishigaki Island at 9 am to receive medical care at Ishigaki Veterinary Clinic. He spent 24 days under their care.[47]

Following the accident he couldn't move on his own, but he regained his ability to walk while on Ishigaki. He was brought back to the Iriomote Wildlife Preservation Center for rehabilitation on August 31. Originally labeled W-48 due to the fact that he was the forty-eighth confirmed sighting of an Iriomote cat on the western part of the island, he eventually was given the name Yon.[47]

Rehabilitation[edit]

By September 2, Yon weighed 1.9 kilograms. Despite his progress, his caretakers noticed a tendency for him to turn to the right because of the effects of his accident.[47]

From the beginning, Yon's caretakers took careful measures in order to avoid acclimation to humans so that one day he could be released back into the wild. Only three staff members were allowed to feed him directly. Other people, including center staff, were only allowed to view him via video camera monitoring. The media were also prohibited from taking direct photographs.[47]

From the time he was discharged until February 3, 1999 Yon's rehabilitation was restricted to a room within the center. Thin logs were used to make a jungle gym so that he would be able to practice walking, jumping, and climbing trees. Rice plants were also grown in his room as a substitute for grass that cats use to help regurgitate. Once he was healthy enough, he was moved to an outdoor cage where he lived until his health began deteriorating on December 20, 2010.[47]

He was permanently handicapped after his accident; his left paw was paralyzed, and he tended to move towards the right.[47]

Death[edit]

On December 20, 2010 Yon was found to be curled up and unmoving near a dried stream. He was brought into the center's rehabilitation room, where it was discovered that he had pulmonary edema which had nearly killed him, however he was able to eat by the next day and gradually got better. He was unable to walk for the remainder of December, though by the end of January he regained his ability to walk, and during February and March he improved enough to be able to walk up and down stairs. However his condition then took a turn for the worse, and he died on the night of April 9 at an estimated fifteen years and one month old. He weighed 3.5 kilograms and was 78.5 centimeters long. He is the oldest Iriomote cat on record.[47]

Influence on research[edit]

Yon was the first Iriomote cat to be kept for an extended period of time, the only to be saved after an accident, and the first to go through rehabilitation. Other Iriomote cats that were rescued either died immediately or shortly after being brought in for care.[47]

Though he was never returned to the wild, the recorded observations of Yon are extremely important regarding Iriomote cat preservation. Every day, records were taken including what he did at what time, weight, and anything else of note. Because of difficulties in researching Iriomote cats in the wild, observations of Yon are currently the best example of the cats' natural behavior. There are also very few cases of the cats being cared for by people, so records of his health care may help injured and sick Iriomote cats in the future.[47]

In culture[edit]

On July 30, 2010, the Taketomi Town Tourist Association invited residents to create a design for a local mascot. A Komi Elementary School sixth grader's design, which was based on the Iriomote cat, was chosen. The island of Iriomote, where Taketomi is located, is pictured on the mascot's chest. It was named in the same manner it was designed; on August 31, 2010 the name "Pikaryaa" (ピカリャ~?) was chosen based on the submission of an Ishigaki resident who drew inspiration from the local nickname of the cat, yamapikaryaa.[48]

Yamapikaryaa[edit]

In general, names such as yamapikaryaa are used in reference to the Iriomote cat, but some locals claim to have seen another type of cat on the island. This cat is described as being twice as large as a house cat with a tail that is 60 centimeters long and a coat pattern that is different from what the Iriomote cat displays. It has been sighted several times.[28] Locals have given it several nicknames. In the neighborhoods of Sonai and Komi they call it kunzumayaa (クンズマヤー?) and toutouyaa (トウトウヤー?), respectively, and on Aragusu Island they call it yamapikaryaa (ヤマピカリャー?). It is not thought to be a house cat, stray cat, or an Iriomote cat.[28][49]

In 1965 Togawa spoke with a local hunter who claimed to have killed a large cat with fur like a tiger's. He disposed of the body, and Haemi on the southern part of the island, where the body was disposed of, was searched.[30] The hunter said that until ten days prior to the interview, the cat's skeleton was still where he had left it, but the recent rains had washed it away.[30] He described that cat as having a shoulder height that reached an adult human's knee, a tail that was 60 centimeters long, a body twice as large as a house cat's, and greenish striped fur.[30]

On June 2, 1982 the Yomiuri Shimbun published an article about yamapikaryaa. An experienced boar hunter claimed to have seen yamapikaryaa about ten times in the mountains around Mount Dedou. He also said that he caught and ate one once. On another occasion, he said he saw an adult female yamapikaryaa with a kitten.[28]

Other articles regarding yamapikaryaa have also been published, including on September 14, 2007. Professor Eiyuu Akiyoshi (秋吉英雄 Akiyoshi Eiyuu) of Shimane University, who was staying on Iriomote in order to research fish, spotted a cat larger than the Iriomote cat with a long tail and spots. He saw the cat on Sakiyama Peninsula (崎山半島 Sakiyama Hantō) on the seldom-visited western part of the island.[50]

Tadaaki Imaizumi (今泉忠明 Imaizumi Tadaaki), on the other hand, spoke with a hunter in 1994 who had the skull of what he believed was a large wild cat. Tadaaki Imaizumi determined that it was a house cat.[28]

Notes[edit]

  1. ^ a b c Izawa, M. (2008). "Prionailurus bengalensis ssp. iriomotensis". IUCN Red List of Threatened Species. Version 2012.2. International Union for Conservation of Nature. 
  2. ^ a b c d e 環境省. イリオモテヤマネコ生息状況等総合調査(第4次)の結果について(お知らせ) [(Fourth) Survey of the State of the Iriomote Cat's Habitat: Regarding the Results (notice)] (in Japanese). Retrieved 10 June 2012. 
  3. ^ 今泉(1994), Pp.8–13, Pp. 144-147
  4. ^ 戸川(1972), Pp.13–92
  5. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab 今泉, 忠明 (1994). イリオモテヤマネコの百科 [Iriomote Wild Cat Encyclopedia] (in Japanese). Data House. pp. 7–48. ISBN 4887182856. 
  6. ^ a b c d e f g h i j k l m n o p q 今泉, 吉典 (1986). 動物大百科1 肉食類 [Encyclopedia of Animals 1: Carnovores] (in Japanese). 平凡社. ISBN 4582545017. 
  7. ^ a b c d e f g h i j k l m 小原, 秀雄 (2000). 動物世界遺産 レッド・データ・アニマルズ4 インド、インドシナ [World Heritage Animals: Red Data Animals 4 India and Indochina] (in Japanese). 講談社. ISBN 4062687542. 
  8. ^ a b c d e f g h i 今泉, 吉典 (1991). 世界の動物 分類と飼育2 (食肉目) [Animals of the World: Types and Rearing 2 (Carnivores)] (in Japanese). 東京動物園協会. ISBN 4886220614. 
  9. ^ a b c d e f g h i j k 沼田, 眞; 渡辺, 景隆 last3=畑 first3=正憲 (2005). 沖縄県の絶滅のおそれのある野生生物(レッドデータおきなわ)-動物編- [Endangered Okinawan Animals (Red Data Okinawa) -Animal Edition-] (pdf) (in Japanese). 沖縄県文化環境部自然保護課編. pp. 25–27. Retrieved 3 June 2012. 
  10. ^ 琉球新報. イリオモテヤマネコ、歯年輪で年齢判別 [Iriomote Cat, Tooth Rings Show Age] (in Japanese). Retrieved 10 June 2012. 
  11. ^ a b c d e f g h i j k l m n o p 今泉, 忠明 (1994). イリオモテヤマネコの百科 [Iriomote Wild Cat Encyclopedia] (in Japanese). Data House. pp. 119–157. ISBN 4887182856. 
  12. ^ a b 加藤, 陸奥雄 (1995). 日本の天然記念物 [Natural Monuments of Japan] (in Japanese). 講談社. pp. 622–623. ISBN 4061805894. 
  13. ^ a b c d e f g h 増田, 隆一 (June 1996). 遺伝子からみたイリオモテヤマネコとツシマヤマネコの渡来と進化起源 [Phylogeny and Evolutionary Origin of the Iriomote Cat and the Tsushima Cat, based on DNA Analysis]. 地學雜誌 (in Japanese) (社団法人東京地学協会) 105 (3): 355–362. ISSN 0022-135X. Retrieved June 3, 2012. 
  14. ^ a b c d e f g h i j k l 環境省 自然環境局 生物多様性センター. 絶滅危惧種情報(動物)- イリオモテヤマネコ - [Critically Endangered Species Information (Mammals) -Iriomote Cat-] (in Japanese). Retrieved 8 June 2012. 
  15. ^ a b c インターネット自然研究所. イリオモテヤマネコ [Iriomote Cat] (in Japanese). Retrieved 10 June 2012. 
  16. ^ Izawa, M., Doi, T., Okamura, M., Nakanishi, N., Murayama, A., Hiyama, T., Oh, D., Teranishi, A., Suzuki, A. (2007). Toward the survival of two endangered felid species of Japan. Pages 120−121 in: Hughes, J., Mercer, R. (eds.) Felid biology and conservation conference 17–20 September: Abstracts. WildCRU, Oxford, UK.
  17. ^ 今泉, 忠明 (1994). イリオモテヤマネコの百科 [Iriomote Wild Cat Encyclopedia] (in Japanese). Data House. pp. 50–75. ISBN 4887182856. 
  18. ^ a b c d e 今泉, 忠明 (2004). 野生ネコの百科 [Wild Cat Encyclopedia] (in Japanese). Data House. ISBN 978-4887187726. 
  19. ^ a b c d e f g h i j 今泉, 忠明 (1994). イリオモテヤマネコの百科 [Iriomote Wild Cat Encyclopedia] (in Japanese). Data House. pp. 75–117. ISBN 4887182856. 
  20. ^ Nakanishi, N., Okamura, M., Watanabe, S., Izawa, M., Doi, T. (2005). The effect of habitat on home range size in the Iriomote Cat Prionailurus bengalensis iriomotensis'. Mammal Study 30: 1–10.
  21. ^ a b c d 西表野生生物保護センター. イリオモテヤマネコについて [About Iriomote Cats] (in Japanese). Retrieved 10 June 2012. 
  22. ^ a b c d e f g h 財団法人 自然環境研究センター (2006). イリオモテヤマネコBOOK [The Iriomote Cat BOOK] (in Japanese). 株式会社高陽堂印刷. 
  23. ^ Sakaguchi, N., Ono, Y. (1994). Seasonal change in the food habits of the Iriomote cat Felis iriomotensis'. Ecological Research 9 (2): 167−174.
  24. ^ 安間, 繁樹 (2001). 琉球列島 生物の多様性と列島のおいたち (in Japanese trans_title=The Ryukyu Archipelago: Diversity of Animals and Island Development). 東海大学出版会. pp. 112–147. ISBN 978-4-48601555-0. 
  25. ^ a b Schmidt, K., Nakanishi, N.,Izawa, M., Okamura, M., Watanabe, S., Tanaka, S. Doi, T. (2009). The reproductive tactics and activity patterns of solitary carnivores: the Iriomote cat. Journal of Ethology 27: 165–174.
  26. ^ a b c Ealey, M. (2011). "Oldest Iriomote wildcat dies aged 15 years one month". Ryukyu Shimpo. Retrieved 9 May 2012. 
  27. ^ Imaizumi, Y. (1966–1967). 琉球, 西表島産の山猫 (新属新種) について [A new genus and species of cat from Iriomote, Ryukyu Islands] (pdf). 哺乳動物学雑誌 (in Japanese) (日本哺乳動物学界) 3: 75–105. ISSN 1884-393X. Retrieved June 8, 2012. 
  28. ^ a b c d e f 今泉, 忠明 (1994). イリオモテヤマネコの百科 [Iriomote Wild Cat Encyclopedia] (in Japanese). Data House. pp. 8–13, 144–147. ISBN 4887182856. 
  29. ^ a b c d e f g h i 戸川, 幸夫 (1972). イリオモテヤマネコ:原始の西表で発見された〝生きた化石動物〟の謎 [Iriomote Cat: the Mystery of the "Living Fossil" Discovered on Primeval Iriomote Island] (in Japanese). 自由国民社. pp. 13–92. 
  30. ^ a b c d e f g 戸川, 幸夫 (1972). イリオモテヤマネコ:原始の西表で発見された〝生きた化石動物〟の謎 [Iriomote Cat: the Mystery of the "Living Fossil" Discovered on Primeval Iriomote Island] (in Japanese). 自由国民社. pp. 93–138. 
  31. ^ a b c d e f g h i j k l 戸川, 幸夫 (1972). イリオモテヤマネコ:原始の西表で発見された〝生きた化石動物〟の謎 [Iriomote Cat: the Mystery of the "Living Fossil" Discovered on Primeval Iriomote Island] (in Japanese). 自由国民社. pp. 139–176. 
  32. ^ 戸川, 幸夫 (1972). イリオモテヤマネコ:原始の西表で発見された〝生きた化石動物〟の謎 [Iriomote Cat: the Mystery of the "Living Fossil" Discovered on Primeval Iriomote Island] (in Japanese). 自由国民社. pp. 177–242. 
  33. ^ Leyhausen, P., Pfleiderer, M. (1999). The systematic status of the Iriomote cat (Prionailurus iriomotensis Imaizumi 1967) and the subspecies of the leopard cat (Prionailurus bengalensis Kerr 1792). Journal of Zoological Systematics and Evolutionary Research 37: 121–131.
  34. ^ Wozencraft, W. C. (2005). "Order Carnivora". In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. p. 543. ISBN 978-0-8018-8221-0. OCLC 62265494. 
  35. ^ Suzuki, Hitoshi; Hosoda first2=Tetsuji; Sakurai, Susumu; Tsuchiya, Kimiyuki; Munechika, Isao; Korablev, Vladimir P. (August 1994). "Phylogenetic relationship between the Iriomote cat and the leopard cat, Felis bengalensis, based on the ribosomal DNA". The Japanese Journal of Genetics (The Genetics Society of Japan) 69 (4): 397–406. doi:10.1266/jjg.69.397. ISSN 0021-504X. 
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  37. ^ Johnson, Warren E. et al. (1999). Molecular Genetic Characterization of Two Insular Asian Cat Species, Bornean Bay Cat and Iriomote Cat. Evolutionary Theory and Processes: Modern Perspectives. pp. 223–248. 
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  39. ^ 琉球新報. 飼い猫の避妊義務化 イリオモテヤマネコ保護 [Desexing of House Cats Becomes Mandatory; Preservation of Iriomote Cats] (in Japanese). Retrieved 10 June 2012. 
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  46. ^ 西表野生生物保護センター. "イリオモテヤマネコを守る!~IWCCの取り組み" [Protect the Iriomote Cats! ~IWCC's Efforts] (in Japanese). Retrieved 10 June 2012. 
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  48. ^ 竹富町観光協会. 竹富町マスコットキャラクター 名前が決定しました! [Taketomi's Mascot's Name is Picked!] (in Japanese). Retrieved 10 June 2012. 
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  50. ^ 琉球新報. 伝説の生物「ヤマピカリャー」? 西表で目撃相次ぐ [The Legendary "Yamapikaryaa"? One Sighting After Another on Iriomote Island] (in Japanese). Retrieved 10 June 2012. 

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