By Holly Schroeder
Geographic Range
Prionailurus iriomotensis is endemic only to Iriomote Island, the southernmost isle in the Ryukyu Archipelago, Japan. The island is approximately 284 km^2. (International Society for Endangered Cats Canada (ISEC Canada), 2001; IUCN Cat Specialist Group - The World Conservation Union, 1996; Okamura et al., 2000; Yasuma, 1988)
Biogeographic Regions:
palearctic 
(native ).
Other Geographic Terms:
island endemic .
Habitat
(1538.32 ft)
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. (International Society for Endangered Cats Canada (ISEC Canada), 2001; IUCN Cat Specialist Group - The World Conservation Union, 1996; Okamura et al., 2000; Yasuma, 1988)
These animals are found in the following types of habitat:
tropical ; terrestrial .
Terrestrial Biomes:
forest ; rainforest ; mountains .
Other:
agricultural ; estuarine .
Physical Description
(7.04 to 9.24 lbs)
(31.5 in)
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. (International Society for Endangered Cats Canada (ISEC Canada), 2001; IUCN Cat Specialist Group - The World Conservation Union, 1996; Okamura et al., 2000; Yasuma, 1988)
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). (International Society for Endangered Cats Canada (ISEC Canada), 2001; IUCN Cat Specialist Group - The World Conservation Union, 1996; Okamura et al., 2000; Yasuma, 1988)
Some key physical features:
endothermic ; homoiothermic; bilateral symmetry .
Sexual dimorphism: sexes alike.
Reproduction
Iriomote cats generally breed once per year.
Breeding is presumed to occur between February and March.
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. (Okamura et al., 2000)
Mating systems:
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). (International Society for Endangered Cats Canada (ISEC Canada), 2001; IUCN Cat Specialist Group - The World Conservation Union, 1996; Okamura et al., 2000)
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. (International Society for Endangered Cats Canada (ISEC Canada), 2001; IUCN Cat Specialist Group - The World Conservation Union, 1996; Okamura et al., 2000)
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. (International Society for Endangered Cats Canada (ISEC Canada), 2001; IUCN Cat Specialist Group - The World Conservation Union, 1996; Okamura et al., 2000)
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. (Okamura et al., 2000)
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. (Okamura et al., 2000)
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.
Lifespan/Longevity
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. (IUCN Cat Specialist Group - The World Conservation Union, 1996)
Behavior
Prionailurus iriomotensis is usually solitary, but may form pairs when breeding. Territories range from 1 to 3 square kilometers. Males have larger territories than females. Male territories can overlap whereas female territories are less likely to do so. Females also exhibit more stable home ranges and seem to use a consistent feeding site for several years, whereas males shift their areas of activity after several months. (Okamura et al., 2000; Yasuma, 1988)
Iriomote cats are active mainly from evening to early morning, but occasionally do hunt during the day, when they apparently prey upon a skink species (Eumeces kishinouyei) that is only diurnal and estivates from dusk till dawn. (Okamura et al., 2000; Yasuma, 1988)
Although they often tracel along the ground, Iriomote cats exhibit arboreal agility. This suggests that they spend some of their time hunting or resting in trees. (Okamura et al., 2000; Yasuma, 1988)
Home Range
Home range sizes for this species range from 1 to 3 square km.
Key behaviors:
arboreal ; terricolous; diurnal ; nocturnal ; crepuscular ; motile ; sedentary ; solitary ; territorial .
Communication and Perception
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. (International Society for Endangered Cats Canada (ISEC Canada), 2001; IUCN Cat Specialist Group - The World Conservation Union, 1996; Okamura et al., 2000; Yasuma, 1988)
Other communication keywords:
pheromones ; scent marks .
Food Habits
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. (Yasuma, 1988)
Primary Diet:
carnivore (eats terrestrial vertebrates).
Animal Foods:
birds; mammals; amphibians; reptiles; fish; insects; aquatic crustaceans.
Predation
There are no documented predators or Iriomote cats.
Ecosystem Roles
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. (Yasuma, 1988)
Economic Importance for Humans: Negative
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. (International Society for Endangered Cats Canada (ISEC Canada), 2001; IUCN Cat Specialist Group - The World Conservation Union, 1996)
Economic Importance for Humans: Positive
Iriomote cats are charismatic, and are becoming a major source of tourist appeal. This brings in economic revenue. (International Society for Endangered Cats Canada (ISEC Canada), 2001; IUCN Cat Specialist Group - The World Conservation Union, 1996)
Ways that people benefit from these animals:
ecotourism .
Conservation Status
IUCN Red List: [link]:
Not Evaluated.
US Federal List: [link]:
Endangered.
CITES: [link]:
Appendix II.
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. (International Society for Endangered Cats Canada (ISEC Canada), 2001; IUCN Cat Specialist Group - The World Conservation Union, 1996)
Other Comments
Establishing a concrete taxonomic status for Iriomote cats is proving to be difficult. A sample study analyzing genetic material suggested that Iriomote cats are in fact a distinct species from P. bengalensis. The population of P. iriomotensis has experienced at least one if not many "extreme demographic bottlenecks". Current evidence suggests that the entire population of this species is derived from as few as two females and one male. (Hemmer, 1978; Johnson et al., 1999)
For More Information
Find Prionailurus iriomotensis information at
Contributors
Holly Schroeder (author), University of Wisconsin-Stevens Point.
Chris Yahnke (editor), University of Wisconsin Stevens Point.
Nancy Shefferly (editor), Animal Diversity Web Staff.
