Megadermatidaefalse vampire bats

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Megadermatids are medium-sized to large bats with a head and body length of 6.5 to 14.0 cm. These "false vampires" or yellow-winged bats are quite distinctive in appearance, with long, erect noseleaves (fleshy protrusion from the nose) and huge ears. Echolocation calls are made through the nose, and the large noseleaf focuses the sound, acting like a megaphone. Megadermatid ears also have a fleshy protrusion called a tragus. The tragus is divided in this family, and the ears are joined at the base by a band of skin across the forehead. There is an extensive tail membrane ( uropatagium), but the tail itself is short or absent.

The megadermatid family includes 4 genera and 5 species. These bats are found in the Old World tropics and subtropics: Central Africa, South Asia, the Malay region, Philippines and Australia.

This family has several distinguishing skull characters. The postorbital process is short or absent, and there are wide supraorbital ridges. The extremely reduced premaxilla appear threadlike and may be lost in skull preparation. Morphologists working with skulls prepared for museum collections originally concluded that the premaxilla were absent in this family, but additional research demonstrated that this was incorrect.

Perhaps the simplest method for identifying a megadermatid skull is to examine the teeth. Megadermatids lack upper incisors, and their large canines have a secondary cusp. Megadermatid species have either 26 or 28 teeth: 2 lower incisors, 1 upper and 1 lower canine, 1 or 2 upper premolars, 2 lower premolars, and 3 upper and lower molars. The molars are large and have a modified dilambdodont cusp pattern.

Megadermatids eat insects or small vertebrates, and none of them feed on blood despite their common name. The carnivorous species eat small vertebrates: fish, frogs, lizards, birds, mice, or other bats. One species (Cardioderma cor) sits on a perch, listens for prey (a passive form of echolocation), and then swoops down on the unsuspecting beetle, centipede, scorpion, or small bat. This species also "sings" to defend its foraging territory from other bats.

Megadermatid wings tend to be short and broad (low aspect ratio) with a relatively large area (low wing loading). This type of wing allows good maneuverability. The second wing digit has only one phalanx, but the third has two.

Bats in this family roost in caves, rock crevices, buildings, or trees. Roosting habits vary from solitary to colonial. One species (Lavia frons) appears to be monogamous. A monogamous mating system is unusual in bats and in mammals as a whole.

The fossil record of this family extends to the late Eocene or early Oligocene.

Technical characters

References and literature cited:

Anderson, S. and J. K. Jones, Jr., 1984. Orders and Families of Recent Mammals of the World. John Wiley and Sons, New York. 686pp.

Feldhamer, G. A., L. C. Drickamer, S. H. Vessey, and J. F. Merritt. 1999. Mammalogy. Adaptation, Diversity, and Ecology. WCB McGraw-Hill, Boston. xii+563pp.

Fenton, M. B., P. Racey, and J.M. V. Rayner (eds.), 1987. Recent Advances in the Study of Bats . Cambridge University Press, Cambridge.

Hill, J. E. and J. D. Smith, 1992. Bats: A Natural History . University of Texas Press, Austin.

Nowak, Ronald M., 1994. Walker's Bats of the World . Johns Hopkins University Press, Baltimore.

Vaughan, T. A., J. M. Ryan, N. J. Czaplewski. 2000. Mammalogy. Fourth Edition. Saunders College Publishing, Philadelphia. vii+565pp.

Contributors

Laurel Hester (author), Phil Myers (author), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

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.

chemical

uses smells or other chemicals to communicate

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.

motile

having the capacity to move from one place to another.

sexual

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

tactile

uses touch to communicate