Pteropus dasymallus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Chiroptera Pteropodidae

Scientific Name: Pteropus dasymallus Temminck, 1825
Common Name(s):
English Ryukyu Flying Fox, Ryukyu Flying-fox
French Renard Volant des Ryukyu, Roussette des Ryukyu
Spanish Zorro Volador De Ryu-kyu
Taxonomic Notes: In Japan, four subspecies are recognized: Pteropus dasymallus dasymallus, P. d. daitoensis (Daito Islands), P. d. inopinatus (Okinawa Islands), and P. d. yayeyamae (Yaeyama Islands). The Taiwan subpopulation represents the subspecies P. d. formosus Sclater, 1873.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A4cd; B2ab(iii,iv,v); C1 ver 3.1
Year Published: 2017
Date Assessed: 2016-12-31
Assessor(s): Vincenot, C.
Reviewer(s): Mildenstein, T.
Contributor(s): Heaney, L., Rosell-Ambal, R.G.B., Tabaranza, B. & Izawa, M.
This species is listed as Vulnerable (VU) based on its small population size and continuing decline (criterion C1), restricted geographic range (criterion B2ab), and considering a time period of three generations (24 years), including both past (12 years) and future (12 years), this species has declined by more than 30% (criterion A4cd). This decline is being caused by habitat degradation, hunting, culling, predation by feral cats and dogs, competition with invasive squirrels (in Taiwan), and synergistic effect of typhoons. If these threats are not addressed promptly in proper conservation programs, a future uplisting to Endangered will be necessary. It should be noted that P. dasymallus was listed as Endangered prior to the 2008 assessment, that currently EN B2 is already partly met under condition b(iii,iv,v) (but not under subcriterion a), and that EN C1 is almost fulfilled. Moreover, out of the five known subspecies, one is on the verge of extinction (P. d. formosus in Taiwan), two are Critically Endangered (P. d. dasymallus and P. d. daitoensis), and the two remaining subspecies are considered Near Threatened (P. d. inopinatus and P. d. yayeyamae). The current absence of conservation efforts on the large majority of the distribution range, the total uncertainty surrounding population sizes and trends, the important threats currently faced, and public attitude towards the species further call for caution.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is found in Japan, the Philippines and Taiwan. In Japan, it is found on the Osumi Islands (Kuchinoerabu), Tokara Islands (Nakano, Taira, Akuseki, Takara), Okinawa Islands, Yaeyama Islands (Ishigaki, Taketomi, Kohama, Iriomote, Hateruma, Kuro, Hatoma, Aragusuku, and Yonaguni), Miyako Islands (Tarama, Irabu, Miyako) and Daito Islands. In the Philippines, it occurs in the small northern islands of Batan, Babuyan Claro, Dalupiri, and Fuga. In Taiwan, a few individuals remain only on Lutao (Green island) and Guishan (Turtle island).
Countries occurrence:
Japan (Nansei-shoto); Philippines; Taiwan, Province of China
Additional data:
Estimated area of occupancy (AOO) - km2:300-600
Extreme fluctuations in area of occupancy (AOO):No
Extreme fluctuations in extent of occurrence (EOO):No
Number of Locations:10Continuing decline in number of locations:Yes
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Population estimates are lacking, except on very few small islands. In Japan, the regional populations in the Okinawa island group (P. d. inopinatus) and Yaeyama island group (P. d. yayeyamae) are the largest and likely number a few thousands of individuals each. In the northern part of the range (P. d. dasymallus), less than 200 individuals are thought to inhabit a handful of islands only. On the two Daito islands, on which population counts have been performed, the subpopulation was estimated at 300-500 individuals and seems stable on Minami-Daito but declining on Minami-Daito, where only 20 individuals remain. In the Philippines, no data is available, but the few reports available seem to indicate a small regional population. In Taiwan, P. d. formosus is on the verge of extinction. It remains on Lutao, where only two bats were found in 2005 (Zhang et al. 2010) and four more recently (S.-F. Chen, pers. comm.), and on Guishan, where a micropopulation was discovered in 2010 (Chao 2010).
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:3000-6000Continuing decline of mature individuals:Yes
Population severely fragmented:No
All individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:This is a solitary fruit bat with a broad diet consisting of fruits (of Ficus spp especially), leaves, and nectar. It is particularly important for seed dispersal, especially at long distance and for large seeds (e.g., Terminalia catappa). In Japan, P. dasymallus roosts in dense forests, and can be seen foraging in forests, orchards, and in urban areas. It rests during the day either alone or in small groups hanging from the branches of trees.
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):6-8

Threats [top]

Major Threat(s): In Japan, forest clearance for construction and land conversion to create new agricultural plantations (especially for sugarcane, banana, and pineapple) reduce the habitat available for P. dasymallus. This fruit bat also faces substantial threat from local illegal culls operated by farmers in response to crop damage (Vincenot et al. 2015b). This problem, which has been largely ignored so far, is particularly destructive in conjunction with typhoons, which result in both direct mortality and further reduction in food availability. This vortex of synergistic threats is particularly alarming, because it remains unacknowledged and unaddressed by researchers and authorities (Vincenot et al. 2017). Predation by cats and dogs is also a major conservation concern. Powerline electrocutions and accidental entanglements have also been reported (Vincenot et al. 2017).

In Taiwan, hunting brought P. d. formosus to extinction on the Taiwanese mainland in the 1970s (Lee et al. 2009). It then remained only on Lutao (also called Green Island), where hunting for export coupled with competition with the invasive Pallas’s Squirrel (Callosciurus erythraeus) rapidly drove the local population from 2,000 individuals to a point at which local extinction was assumed. After several unsuccessful searches for remaining individuals in the 1990s, a recent survey however found four individuals left on the island (S.-F. Chen pers. comm). P. d. formosus has recently been reported to subsist in very small numbers on Guishan (also called Steep or Turtle Island). Studies are needed to assess possible threat factors present at this last location.

In the Philippines, intensive poaching is occurring on some islands (e.g., Babuyan Claro), where P. dasymallus is favoured as a delicacy amongst locals (Oliveros et al. 2004). Other potential threat factors are unknown, as this regional population remains unstudied.

Conservation Actions [top]

Conservation Actions: The species was included in Appendix II of CITES in 1990. In Japan, dasymallus and daitoensis are listed as Critically Endangered (CR IA) in the Japanese Red List (2012), have been designated as Natural Monuments, and the latter also as a Domestic Endangered Species. Inopinatus and Yayeyamae are listed as Near-Threatened (NT) by Okinawa Prefecture (2005). In the Red List of China, P. d. formosus is considered Endangered (EN) (Zhang et al. 2010).

Classifications [top]

1. Forest -> 1.6. Forest - Subtropical/Tropical Moist Lowland
suitability:Suitable  major importance:Yes
1. Forest -> 1.7. Forest - Subtropical/Tropical Mangrove Vegetation Above High Tide Level
14. Artificial/Terrestrial -> 14.3. Artificial/Terrestrial - Plantations
14. Artificial/Terrestrial -> 14.4. Artificial/Terrestrial - Rural Gardens
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 -> 4.2. Training
4. Education & awareness -> 4.3. Awareness & communications
5. Law & policy -> 5.4. Compliance and enforcement -> 5.4.2. National level
5. Law & policy -> 5.4. Compliance and enforcement -> 5.4.3. Sub-national level
6. Livelihood, economic & other incentives -> 6.4. Conservation payments

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Conservation sites identified:Yes, over entire range
In-Place Species Management
In-Place Education
  Included in international legislation:Yes
  Subject to any international management/trade controls:Yes
10. Geological events -> 10.1. Volcanoes
♦ timing:Past, Likely to Return ♦ scope:Minority (<50%) ♦ severity:Unknown ⇒ Impact score:Past Impact 
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 2. Species Stresses -> 2.1. Species mortality

1. Residential & commercial development -> 1.2. Commercial & industrial areas
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Slow, Significant Declines ⇒ Impact score:Low Impact: 5 
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 2. Species Stresses -> 2.3. Indirect species effects -> 2.3.8. Other

11. Climate change & severe weather -> 11.3. Temperature extremes
♦ timing:Unknown ♦ scope:Whole (>90%) ♦ severity:Unknown ⇒ Impact score:Unknown 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

11. Climate change & severe weather -> 11.4. Storms & flooding
♦ timing:Ongoing ♦ scope:Whole (>90%) ♦ severity:Causing/Could cause fluctuations ⇒ Impact score:Medium Impact: 7 
→ Stresses
  • 1. Ecosystem stresses -> 1.3. Indirect ecosystem effects
  • 2. Species Stresses -> 2.2. Species disturbance

2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.2. Small-holder farming
♦ timing:Ongoing ♦ scope:Whole (>90%) ♦ severity:Slow, Significant Declines ⇒ Impact score:Medium Impact: 7 
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion
  • 2. Species Stresses -> 2.3. Indirect species effects -> 2.3.8. Other

5. Biological resource use -> 5.1. Hunting & trapping terrestrial animals -> 5.1.1. Intentional use (species is the target)
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Rapid Declines ⇒ Impact score:Medium Impact: 6 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

5. Biological resource use -> 5.1. Hunting & trapping terrestrial animals -> 5.1.3. Persecution/control
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Rapid Declines ⇒ Impact score:Medium Impact: 6 
→ Stresses
  • 2. Species Stresses -> 2.1. Species mortality

8. Invasive and other problematic species, genes & diseases -> 8.1. Invasive non-native/alien species/diseases -> 8.1.2. Named species [ Callosciurus erythraeus ]
♦ timing:Ongoing ♦ scope:Minority (<50%) ♦ severity:Slow, Significant Declines ⇒ Impact score:Low Impact: 5 
→ Stresses
  • 2. Species Stresses -> 2.3. Indirect species effects -> 2.3.2. Competition

1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
1. Research -> 1.5. Threats
1. Research -> 1.6. Actions
3. Monitoring -> 3.1. Population trends

Bibliography [top]

Camargo, S.J., Robertson, A.W., Gaffney, S.J., Smyth, P. and Ghil, M. 2007. Cluster analysis of typhoon tracks. Part I: General properties. Journal of Climate 20(14): 3635-3653.

Chao, V.Y. 2010. Giant bat species reemerges after 30 years on edge, Taipei Times.

IUCN. 2017. The IUCN Red List of Threatened Species. Version 2017-2. Available at: (Accessed: 14 September 2017).

Lee, Y.F., Takaso, T., Chiang, T.Y., Kuo, Y.M., Nakanishi, N., Tzeng, H.Y. and Yasuda, K. 2009. Variation in the nocturnal foraging distribution of and resource use by endangered Ryukyu flying foxes (Pteropus dasymallus) on Iriomotejima Island. Japan Contrib. Zool. 78: 51-64.

Lin, Y.-C., Chang, T.-J., Lu, M.-M. and Yu, H.-L. 2015. space-time typhoon trajectories analysis in the vicinity of Taiwan. Stoch Environ Res Risk Assess 29: 1857.

Ministry of Environment (ed.). 2012. Japanese Red Data Book [in Japanese]. Japan Integrated Biodiversity Information System.

Okinawa Prefecture. 2005. Revised Edition of the Okinawa Red Data Book) (in Japanese).

Oliveros, C., Broad, G., Pedregosa, M., Espaňola, C., Reyes, M., Garcia, H.J., Gonzalez, J.C., Bajarias, Jr., A. 2004. An avifaunal survey of the Babuyan Islands, Northern Philippines with notes on mammals, reptiles and amphibians, 29 March-6 June 2004. Unpublished report, Manilla.

Trenberth, K. 2005. Uncertainty in hurricanes and global warming. Science 308: 1753-1754.

Tsuboki, K., Yoshioka, M.K., Shinoda, T., Kato, M., Kanada, S. and Kitoh, A. 2015. Future increase of supertyphoon intensity associated with climate change. Geophys. Res. Lett. 42: 646-652.

Vincenot, C.E., Collazo, A.M. and Russo, D. 2017. The Ryukyu flying fox (Pteropus dasymallus) — A review of conservation threats and call for reassessment. Mammalian Biology - Zeitschrift für Säugetierkunde (in press).

Vincenot, C.E., Collazo, A.M., Wallmo, K. and Koyama, L. 2015a. Public awareness and perceptual factors in the conservation of elusive species: the case of the endangered Ryukyu flying fox. Global Ecol. Conservation 3: 526-540.

Vincenot, C.E., Koyama, L. and Russo, D. 2015b. Near threatened? First report of unsuspected human-driven decline factors in the Ryukyu flying fox (Pteropus dasymallus) in Japan. Mammalian Biology—Zeitschrift für Säugetierkunde 80: 273-277.

Citation: Vincenot, C. 2017. Pteropus dasymallus. The IUCN Red List of Threatened Species 2017: e.T18722A22080614. . Downloaded on 25 September 2017.
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