Critically endangered bats



Singapore Infopedia

Background

Bats belong to an order of mammals known as Chiroptera1, a term that comes from the Greek words cheiro (“hand”) and ptera (“wing”), aptly describing their most distinctive feature.2 Bats contribute to the ecosystem by aiding in floral pollination and seed dispersal.3 There are about 1,000 species of bats in the world,4 and 30 have been documented in Singapore.The Singapore Red Data Book (2008) classifies seven species of bats as “critically endangered”, just one step away from local extinction.6 They are threatened mainly by habitat loss. Conservation would thus require protecting their habitats and minimising human disturbance.7

List of Critically Endangered Bat Species
- Brown tube-nosed bat (Murina suilla), also known as lesser tube-nosed bat8

- Lesser bamboo bat (Tylonycteris pachypus),9 also called club-footed bat, flat-headed bat, lesser flat-headed bat10
- Lesser false vampire (Megaderma spasma), otherwise known as Malayan false vampire, lesser false vampire bat11
- Lesser sheath-tailed bat (Emballonura monticola)12
- Naked bulldog bat (Cheiromeles torquatus),13 also called greater naked bat or hairless bat14
- Southeast Asian hollow-faced bat (Nycteris tragata),15, also known as Malayan slit-faced bat16
- Trefoil horseshoe bat (Rhinolophus trifoliatus)17

Physical Description
Bats are the only mammals that can fly, with their wings providing both lift and thrust, whereas other mammals that appear to “fly” (such as flying squirrels) are merely gliding through the air.18 All bats have a similar wing structure that is easily distinguished from that of birds.19 Their wings are formed from skin stretched between the forearms and the hind legs and between elongated fingers.20 But other than sharing this basic wing structure, bats vary greatly in their size and physical appearance.21


The lesser bamboo bat and lesser sheath-tailed bat are very small, weighing just 3.5−5.0 g and 4.5−5.5 g respectively.22 The trefoil horseshoe bat, Southeast Asian hollow-faced bat, and lesser false vampire are relatively larger, weighing 10−20 g, 12−22 g, and 18−28 g respectively.23

Bats also differ greatly in their tail length, if they have a tail at all, and in the size of their ears.24 For instance, the lesser false vampire has no visible tail,25 while the lesser sheath-tailed bat has a short tail measuring 11−14 mm long,26 and the Southeast Asian hollow-faced bat has a very long tail ranging from 65 to 72 mm long.27 However, in terms of ear length, the lesser false vampire has very large ears (30−42 mm), whereas those of the lesser sheath-tailed bat and lesser bamboo bat are fairly small (12−13 mm and 8−9 mm respectively).28

Facial features are just as diverse.29 Some species have a fleshy flap-like structure on the nose called a nose leaf, but even among various species, they can look very different.30 It is believed that the nose leaf helps in the transmission of echolocation signals.31 Bat species with nose leaves include the Southeast Asian hollow-faced bat, lesser false vampire and trefoil horseshoe bat, whereas the lesser sheath-tailed bat and lesser bamboo bat have simple muzzles without any noseleaf.32

Excluding their wing membranes, most bats are well covered with hair.33 One exception is the naked bulldog bat, which is almost entirely hairless.34 The hair protects the underlying skin and insulates the body, and some bats have patterns in their hair that may have a camouflage purpose.35 Fur colour, length and texture vary between species.36 For example, the trefoil horseshoe bat has long and woolly fur that ranges from pale yellowish-brown to greyish-brown.37 The lesser bamboo bat has short and fluffy fur with brown to reddish-brown upper parts and slightly paler underparts that are usually tinged orange.38

Echolocation
Most bat species use echolocation to locate objects, including prey, either during flight or when they are stationary.39 The trefoil horseshoe bat, for instance, is known to hunt by hanging from an open branch and using echolocation to find approaching insects.40 Echolocation works like sonar, where the bat emits sounds into its surroundings and listens to the echoes that return.41 The use of this method to find their way may have contributed to the common myth that bats are blind.42 Bats can see, though their eyes are specially adapted for night-time vision as they are largely nocturnal.43


Reproduction
Like other mammals, bats give birth to live young.44 Females usually produce a single offspring, and new-borns are fed their mother’s milk.45


Diet
Most bats feed mainly on insects.46 Some survive on fruit and nectar.47 Some species feed on small vertebrates such as lizards, frogs and other bats.48 Vampire bats, of course, are known to feed on blood.49


All seven species of critically endangered bats in Singapore feed primarily on insects.50 The lesser false vampire is not a true vampire bat, because it does not drink blood.51 Its diet consists chiefly of insects, but it is also known to eat other small animals including bats and lizards.52

Habitat
Bats are often found in forests, though some inhabit urban and cultivated areas.53 Roosting locations vary.54 The naked bulldog bat, lesser false vampire and Southeast Asian hollow-faced bat roost in caves, hollow trees and buildings, though tunnels and old wells host the latter two species as well.55 In contrast, the lesser sheath-tailed bat roosts in fairly exposed locations such as rock shelters, hollow logs, between boulders, under fallen tree trunks and under overhanging earth banks.56 The trefoil horseshoe bat is more selective, usually roosting among the dense foliage of trees.57 The lesser bamboo bat is even more specific ─ it roosts in hollows between the nodes of bamboo stems, entering and exiting through small slits made by beetles.58


Distribution
In Singapore, these endangered bats have been recorded in Bukit Timah Nature Reserve (lesser bamboo bat, lesser sheath-tailed bat), Central Catchment Nature Reserve (Southeast Asian hollow-faced bat, trefoil horseshoe bat), Pulau Tekong (brown tube-nosed bat, lesser false vampire, trefoil horseshoe bat) and Pulau Ubin (lesser false vampire).59


Elsewhere in Southeast Asia, they can be found in Peninsular Malaysia, Thailand, Indonesia (including Sumatra and Java) and the island of Borneo (divided between Malaysia, Indonesia and Brunei).60 With the exception of the brown tube-nosed bat and naked bulldog bat, they also occur in Myanmar.61 Some are also found in the Philippines (lesser bamboo bat, lesser false vampire, naked bulldog bat) and in Laos, Vietnam and Cambodia (lesser bamboo bat, lesser false vampire).62 Some are found outside of Southeast Asia: in China (lesser bamboo bat, trefoil horseshoe bat), India (lesser bamboo bat, lesser false vampire, trefoil horseshoe bat), Bangladesh (lesser bamboo bat, lesser false vampire) and Sri Lanka (lesser false vampire).63



Author
Valerie Chew




References
1. Wild Animals of Singapore: A Photographic Guide to Mammals, Reptiles, Amphibians and Freshwater Fishes (Singapore: Draco Publishing and Distribution; Nature Society (Singapore), 2008), 130. (Call no. RSING 591.95957 WIL)

2. R. M. Nowak, Walker's Bats of the World (Baltimore: Johns Hopkins University Press, 1994), 5 (Call no. R 599.4 NOW); M. B. Fenton, Bats (New York: Facts on File, 1992), 1. (Call no. R 599.4 FEN)
3. Leong Tzi Ming and Chan Kwok Wai, "Bats in Singapore–Ecological Roles and Conservation Needs," In Proceedings of Nature Society Singapore Conference: Nature Conservation for a Sustainable Singapore, Singapore, 16 October 2011 (Singapore: Nature Society Singapore, 2013), 41.
4. “Bat Man Has a Secret Mission on Pulau Ubin,” Straits Times, 26 May 2017, 11. (From NewspaperSG)
5. D. J. W. Lane, T.Kingston and B. P.Y-H. Lee, “Dramatic Decline in bat Species Richness in Singapore, with Implications for Southeast Asia,” Biological Conservation 131 (2006), 584−93, 10.1016/j.biocon.2006.03.005.
6. G. W. H., Davison, P. K. L. Ng and H. C. Ho, eds. The Singapore Red Data Book: Threatened Plants & Animals of Singapore (Singapore: Nature Society (Singapore), 2008), 192−97. (Call no. RSING 591.68095957 SIN)
7. Davison, Ng and Ho, Singapore Red Data Book, 192−97. (Call no. RSING 591.68095957 SIN)
8. Davison, Ng and Ho, Singapore Red Data Book, 197.
9. Davison, Ng and Ho, Singapore Red Data Book, 196.
10. “Lesser Bamboo Bat,” International Union for Conservation of Nature and Natural Resources, updated 31 August 2008, http://www.iucnredlist.org/details/22577/0.
11. Davison, Ng and Ho, Singapore Red Data Book, 195; Wild Animals of Singapore, 147.
12. Davison, Ng and Ho, Singapore Red Data Book, 194.
13. Davison, Ng and Ho, Singapore Red Data Book, 197.
14. Nowak, Walker's Bats of the World, 246−47.
15. Davison, Ng and Ho, Singapore Red Data Book, 195.
16. Charles M. Francis, A Field Guide to the Mammals of South-East Asia (London: New Holland, 2008), 207. (Call no. RSEA 599.0959 FRA)
17. Davison, Ng and Ho, Singapore Red Data Book, 196.
18. Francis, Field Guide to the Mammals of South-East Asia, 192; Nowak, Walker's Bats of the World, 5.
19. Fenton, Bats, 1.
20. Wild Animals of Singapore, 130.
21. Francis, Field Guide to the Mammals of South-East Asia, 192.
22. Francis, Field Guide to the Mammals of South-East Asia, 204, 249.
23. Francis, Field Guide to the Mammals of South-East Asia, 207, 208, 210.
24. Francis, Field Guide to the Mammals of South-East Asia, 192−261.
25. Francis, Field Guide to the Mammals of South-East Asia, 208.
26. Francis, Field Guide to the Mammals of South-East Asia, 204.
27. Francis, Field Guide to the Mammals of South-East Asia, 207.
28. Francis, Field Guide to the Mammals of South-East Asia, 204, 208, 249.
29. Fenton, Bats, 43.
30. Nowak, Walker's Bats of the World, 110.
31. Fenton, Bats, 1.
32. Francis, Field Guide to the Mammals of South-East Asia, 204, 207, 208, 210, 249.
33. Fenton, Bats, 104.
34. Nowak, Walker's Bats of the World, 246−47.
35. Fenton, Bats, 104.
36. Fenton, Bats, 104−105.
37. Francis, Field Guide to the Mammals of South-East Asia, 210.
38. Francis, Field Guide to the Mammals of South-East Asia, 249.
39. “Place Your Bats,” Straits Times, 15 June 2005, 6. (From NewspaperSG)
40. Francis, Field Guide to the Mammals of South-East Asia, 210.
41. Nowak, Walker's Bats of the World, 9.
42. Fenton, Bats, 186.
43. Nowak, Walker's Bats of the World, 186.
44. Fenton, Bats, 1.
45. Fenton, Bats, 1. ; Nowak, Walker's Bats of the World, 19−20.
46. Fenton, Bats, 1.
47. Wild Animals of Singapore, 130.
48. Fenton, Bats, 1.
49. Fenton, Bats, 1.
50. Francis, Field Guide to the Mammals of South-East Asia, 204, 207, 208, 210, 249.
51. Francis, Field Guide to the Mammals of South-East Asia, 208; Wild Animals of Singapore, 147.
52. Francis, Field Guide to the Mammals of South-East Asia, 208.
53. Davison, Ng and Ho, Singapore Red Data Book, 192−97.
54. Davison, Ng and Ho, Singapore Red Data Book, 192−97.
55. Davison, Ng and Ho, Singapore Red Data Book, 192−97.
56. Davison, Ng and Ho, Singapore Red Data Book, 192−97.
57. Davison, Ng and Ho, Singapore Red Data Book, 196.
58. Davison, Ng and Ho, Singapore Red Data Book, 196.
59. Davison, Ng and Ho, Singapore Red Data Book, 192−97.
60. Davison, Ng and Ho, Singapore Red Data Book, 192−97.
61. Davison, Ng and Ho, Singapore Red Data Book, 192−97.
62. Davison, Ng and Ho, Singapore Red Data Book, 192−97.
63. Davison, Ng and Ho, Singapore Red Data Book, 192−97.



List of Images
G. W. H., Davison, P. K. L. Ng and H. C. Ho, eds. The Singapore Red Data Book: Threatened Plants & Animals of Singapore (Singapore: Nature Society (Singapore), 2008), 194–97. (Call no. RSING 591.68095957 SIN)



The information in this article is valid as of December 2023 and correct as far as we are able to ascertain from our sources. It is not intended to be an exhaustive or complete history of the subject. Please contact the Library for further reading materials on the topic. 

 


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