Critically endangered bats
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Bats belong to an order of mammals known as Chiroptera, a term which comes from the Greek words cheiro ("hand") and ptera ("wing"), aptly describing their most distinctive feature. There are about 1,100 species of bats in the world 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. They are threatened mainly by habitat loss; conservation would thus require an effective protection of their habitats and keeping human disturbance to a minimum.
List of Critically Endangered Bat Species
- Brown tube-nosed bat (Murina suilla), also known as lesser tube-nosed bat
- Lesser bamboo bat (Tylonycteris pachypus), also called club-footed bat, flat-headed bat, lesser flat-headed bat
- Lesser false vampire (Megaderma spasma), otherwise known as Malayan false vampire, common Asian ghost bat, lesser false vampire bat
- Lesser sheath-tailed bat (Emballonura monticola)
- Naked bulldog bat (Cheiromeles torquatus), also called greater naked bat or hairless bat
- Southeast Asian hollow-faced bat (Nycteris tragata), also known by the name Malayan slit-faced bat
- Trefoil horseshoe bat (Rhinolophus trifoliatus)
Bats are the only mammals that can truly 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. All bats have a similar wing structure that is easily distinguished from that of birds. Their wings are formed from skin stretched between the forearms and the hind legs and between elongated fingers. But other than sharing this basic wing structure, bats can vary greatly in their size and physical appearance.
The lesser bamboo bat and lesser sheath-tailed bat are very small, weighing just 3.5-5.0g and 4.5-5.5g, respectively. The trefoil horseshoe bat, Southeast Asian hollow-faced bat and lesser false vampire are relatively larger, weighing 10-20g, 12-22g and 18-28g, respectively.
Bats also differ greatly in their tail length, if they have a tail at all, and in the size of their ears. For instance, the lesser false vampire has no visible tail while the lesser sheath-tailed bat has a short tail measuring 11-14mm long, and the Southeast Asian hollow-faced bat has a very long tail ranging from 65mm to 72mm long. However, in terms of ear length, the lesser false vampire has very large ears (30-42mm), whereas those of the lesser sheath-tailed bat and lesser bamboo bat are fairly small (12-13mm and 8-9mm, respectively).
Facial features are just as diverse. One feature that would be immediately noticeable in some bats but absent in others is a fleshy flap-like structure on the nose called the noseleaf, though the noseleaf of one bat species can look very different from that of another. It is believed that the noseleaf helps in the transmission of echolocation signals. Bat species with noseleafs 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.
Excluding their wing membranes, most bats are well covered with fur. One exception is the naked bulldog bat, which is almost entirely hairless. The fur protects the underlying skin and insulates the body, and some bats have patterns in their fur that may have a camouflage purpose. Fur colour, length and texture vary between species. For example, the trefoil horseshoe bat has long and woolly fur that ranges from pale yellowish-brown to greyish-brown. On the other hand, 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.
Most bat species use echolocation to locate objects, including prey, either during flight or when they are stationary. The trefoil horseshoe bat, for instance, is known to hunt by hanging from an open branch and echolocating to find approaching insects. Echolocation works like sonar, whereby the bat emits sounds into its surroundings and listens to the echoes that return. The use of this method to find their way may have contributed to the common myth that bats are blind. Bats actually can see, though their eyes are specially adapted for nighttime vision as they are largely nocturnal.
Like other mammals, bats give birth to live young. Females usually produce a single offspring and newborns are fed their mother's milk.
Most bats feed mainly on insects. Some survive mainly on fruit and nectar. There are also some that eat small vertebrates such as lizards, frogs and other bats. Vampire bats, of course, are known to feed on blood.
All seven species of critically endangered bats in Singapore feed primarily on insects. The lesser false vampire is not a true vampire bat because it does not drink blood. Its diet consists chiefly of insects, but it is also known to eat other small animals including bats and lizards.
Bats are often found in forests, though some inhabit urban and cultivated areas. Roosting locations vary. 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. 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. The trefoil horseshoe bat is more selective, usually roosting among the dense foliage of trees. 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.
In Singapore, these endangered bats have been recorded from 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).
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). With the exception of the brown tube-nosed bat and naked bulldog bat, they also occur in Myanmar. Some are also distributed in the Philippines (lesser bamboo bat, lesser false vampire, naked bulldog bat) and in Laos, Vietnam and Cambodia (lesser bamboo bat, lesser false vampire). A few of the species are found farther afield as well, 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).
Davison, G. W. H., Ng, P. K. L., & Ho, H. C. (Eds.). (2008). The Singapore red data book: Threatened plants & animals of Singapore. Singapore: Nature Society (Singapore).
(Call no.: RSING 591.68095957 SIN)
Fenton, M. B. (c1992). Bats. New York: Facts on File.
(Call no.: R 599.4 FEN)
Francis, C. M. (2008). A field guide to the mammals of South-East Asia. London: New Holland.
(Call no.: RSEA 599.0959 FRA)
International Union for Conservation of Nature and Natural Resources. (2008). The IUCN red list of threatened species. Retrieved May 12, 2009, from http://www.iucnredlist.org/
Lane, D. J. W., Kingston, T., & Lee, B. P.Y-H. (2006). Dramatic decline in bat species richness in Singapore, with implications for Southeast Asia. Biological Conservation, 131. Retrieved May 12, 2009, from http://www.mbcru.com/index_files/Lane%20et%20al.%202006.pdf
Nowak, R. M. (1994). Walker's bats of the world. Baltimore: Johns Hopkins University Press.
(Call no.: R 599.4 NOW)
Place your bats. (2005, June 15). The Straits Times. Retrieved March 7, 2011, from NewspaperSG.
Wild animals of Singapore: A photographic guide to mammals, reptiles, amphibians and freshwater fishes. (2008). Singapore: Draco Publishing and Distribution; Nature Society (Singapore).
(Call no.: RSING 591.95957 WIL)
List of Images
Davison, G. W. H., Ng, P. K. L., & Ho, H. C. (Eds.). (2008). The Singapore red data book: Threatened plants & animals of Singapore (pp.194-197). Singapore: Nature Society (Singapore).
(Call no.: RSING 591.68095957 SIN)
The information in this article is valid as at 2009 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.