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Prionailurus iriomotensisIriomote cat

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. ("Iriomote cat", 2001; "Iriomote cat", 1996; Okamura, et al., 2000; Yasuma, 1988)

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. ("Iriomote cat", 2001; "Iriomote cat", 1996; Okamura, et al., 2000; Yasuma, 1988)

  • Range elevation
    0 to 469 m
    0.00 to 1538.71 ft

Physical Description

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. ("Iriomote cat", 2001; "Iriomote cat", 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). ("Iriomote cat", 2001; "Iriomote cat", 1996; Okamura, et al., 2000; Yasuma, 1988)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    3.2 to 4.2 kg
    7.05 to 9.25 lb
  • Average length
    70-90 cm
    in

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. (Okamura, et al., 2000)

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). ("Iriomote cat", 2001; "Iriomote cat", 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. ("Iriomote cat", 2001; "Iriomote cat", 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. ("Iriomote cat", 2001; "Iriomote cat", 1996; Okamura, et al., 2000)

  • 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

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. ("Iriomote cat", 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 (Plestiodon 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)

  • Average territory size
    1-3 km^2

Home Range

Home range sizes for this species range from 1 to 3 square km.

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. ("Iriomote cat", 2001; "Iriomote cat", 1996; Okamura, et al., 2000; Yasuma, 1988)

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: Positive

Iriomote cats are charismatic, and are becoming a major source of tourist appeal. This brings in economic revenue. ("Iriomote cat", 2001; "Iriomote cat", 1996)

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. ("Iriomote cat", 2001; "Iriomote cat", 1996)

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. ("Iriomote cat", 2001; "Iriomote cat", 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)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Holly Schroeder (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor), University of Wisconsin-Stevens Point.

Glossary

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

diurnal
  1. active during the day, 2. lasting for one day.
ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

estuarine

an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity.

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

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.

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.

Hemmer, H. 1978. The Evolutionary Systematics of Living Felidae: Present Status and Current Problems. Carnivore, 1(1): 71-79.

Johnson, W., F. Shinyashiki, M. Menotti Raymond, C. Driscoll, C. Leh, S. Wasser . 1999. Molecular Genetic Characterization of Two Insular Asian Cat Species, Bornean Bay Cat and Iriomote Cat. Pp. 223-248 in Evolutionary Theory and Processes: Modern Perspectives. Klewar Academic Publishers.

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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