Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Rodentia Muridae

Scientific Name: Tokudaia muenninki
Species Authority: (Johnson, 1946)
Common Name(s):
English Okinawa Spiny Rat, Muennink's Spiny Rat

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(iii,v) ver 3.1
Year Published: 2008
Date Assessed: 2008-06-30
Assessor(s): Ishii, N. & Kaneko, Y.
Reviewer(s): Amori, G. (Small Nonvolant Mammal Red List Authority) & Chanson, J. (Global Mammal Assessment Team)
Listed as Critically Endangered as the extent of occurrence is around 100 km2, the species' habitat is severely fragmented, and there is a continuing decline in the extent and quality of the species' habitat due to deforestation, and a decline in the number of individuals due to predation by introduced species.
Previously published Red List assessments:
2000 Critically Endangered (CR)
1996 Endangered (EN)
1994 Vulnerable (V)

Geographic Range [top]

Range Description: This species is endemic to Okinawa Island, Ryukyu Islands, Japan. It is found only on the northern part (Yanbaru area) of the island, above 300 m asl.
Countries occurrence:
Japan (Nansei-shoto)
Lower elevation limit (metres): 300
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Population density estimates were of 1.8/ha in 1978 and the population is currently considered to be severely declining (Japan RDB 2002). A 1994 survey on Mount Yonahadake did not find any individuals, in a place where one was caught in 1974 (Japan RDB 2002). Surveys in the late 1970s found that the species was relatively easy to catch, but no specimens have been recorded for 35 years since 1978. However, in 2008 live specimens were recorded (F. Yamada pers. comm.).
Current Population Trend: Decreasing
Additional data:
Population severely fragmented: Yes

Habitat and Ecology [top]

Habitat and Ecology: The species inhabits forest (chinquapins) over 30 years old in the northern part of the island (Japan RDB 2002). It prefers forests with high undergrowth (Abe et al. 2005), and has also been found in chinquapin forests surrounded by sugarcane fields (Abe et al. 2005).
Systems: Terrestrial

Threats [top]

Major Threat(s): On the island, deforestation is a major threat, mainly through government forestry programs (Japan RDB 2002). Also, feral cats in the forest predate this species, which has been speculated to be a factor in population declines (Japan RDB 2002, Abe et al. 2005).

Conservation Actions [top]

Conservation Actions: Full protection for all of the Yanbaru region of Okinawa Island is recommended. Management or control of introduced predators is also needed. A conservation education program using this species, as well as Okinawa Rail and Okinawa Woodpecker as flagship species would be beneficial. It is listed as Critically Endangered (CR) in the Japanese Red List (2007).

Classifications [top]

1. Forest -> 1.4. Forest - Temperate
suitability: Suitable  
1. Land/water protection -> 1.1. Site/area protection
2. Land/water management -> 2.1. Site/area management
2. Land/water management -> 2.2. Invasive/problematic species control
4. Education & awareness -> 4.1. Formal education
4. Education & awareness -> 4.3. Awareness & communications

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
In-Place Species Management
In-Place Education
5. Biological resource use -> 5.3. Logging & wood harvesting -> 5.3.5. Motivation Unknown/Unrecorded
♦ timing: Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

8. Invasive & other problematic species & genes -> 8.1. Invasive non-native/alien species -> 8.1.2. Named species (Felis catus)
♦ timing: Ongoing    
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

2. Conservation Planning -> 2.1. Species Action/Recovery Plan

Bibliography [top]

Abe, H., Ishii, N., Ito, T., Kaneko, Y., Maeda, K., Miura, S. and Yoneda, M. 2005. A Guide to the Mammals of Japan. Tokai University Press, Kanagawa, Japan.

IUCN. 2008. 2008 IUCN Red List of Threatened Species. Available at: (Accessed: 5 October 2008).

Kaneko, Y. 2001. Morphological discrimination of the Ryukyu spiny rat (genus Tokudaia) between the islands of Okinawa and Amami Oshima, in the Ryukyu Islands, southern Japan. Mammal Study 26(1): 17-33.

Ministry of the Environment. 2007. The revised Japanese Red List.

Suzuki, H., Tsuchiya, K. and Takezaki, N. 2000. A molecular phylogenetic framework of the Ryukyu endemic rodents Tokudai osimensis and Diplothrix legata. Molecular phylogenetics and Evolution 15: 15-24.

Citation: Ishii, N. & Kaneko, Y. 2008. Tokudaia muenninki. The IUCN Red List of Threatened Species 2008: e.T21972A9342117. . Downloaded on 10 October 2015.
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