SLIT-FACED BATS: Nycteridae

PHYSICAL CHARACTERISTICS

Slit-faced bats are small to medium in size. Head and body length is 1.6 to 3.7 inches (4 to 9.3 centimeters), and adults weigh 0.2 to 1.2 ounces (6 to 36 grams). Also called hollow-faced bats, the feature that gives slit-faced bats their name is a deep groove that runs from their nostrils to a pit in the middle of their forehead. The dent is hidden by fur, which makes it hard to see.

Species of slit-faced bats have large, oval ears and their wings are broad. Slit-faced bats range in color from orange, brown, and red to gray. These bats also have a distinctive feature among mammals at the end of their tail. The long tail, completely enclosed within a membrane, ends in a T-shaped tip.

GEOGRAPHIC RANGE

Slit-faced bats are found throughout most of Africa, Southeast Asia, and Madagascar. Most species are found in Africa.

HABITAT

Some species of slit-faced bats live in woodland savanna or dry country, and others live in rainforests in Africa or in Southeast Asia.

DIET

A slit-faced bat's diet depends upon the species. Most species of these bats feed primarily on a variety of arthropods (animals that have jointed bodies and limbs), such as moths, butterflies, beetles, crickets, centipedes, scorpions, and spiders. Some bats, the larger slit-faced bats, will also eat small vertebrates (animals with a backbone), such as frogs, birds, fish, other bats, and mice.

BEHAVIOR AND REPRODUCTION

Like all bats, these bats are nocturnal, meaning they are active at night. Slit-faced bats also use echolocation (eck-oh-loh-KAY-shun), the detection of an object by means of reflected sound. It is not known how much they depend upon echolocation to catch their prey (animals hunted for food). The echolocation calls of these bats are low in intensity, or energy, and brief. Usually the calls last only a millisecond or less.

As well as echolocation, it appears that these bats depend upon sound to find food. Their large ears are apparently used to listen for the low-frequency sounds of prey-generated movements, such as the sound of an insect scuffling along the ground or calls the insects may make. Slit-faced bats sometimes catch their prey in the air, but primarily snatch their prey from a surface, such as a leaf or branch.

The broad wings of slit-faced bats enable them to fly slowly and hover, then pluck insects off ground or vegetation surfaces. When bats, such as the large slit-faced bat, catch and kill larger prey such as small vertebrates, they carry them off to their feeding perch. These bats can hunt either lying in wait on their perches or from slow, continuous flight low to the ground. When they eat insects, they typically drop their wings and legs.

Like all bats, slit-faced bats are active in the night hours and they roost (settle or rest) during the day hours. Most species shelter alone, in pairs, or in small family groups or colonies (group of animals of the same type living together). Roosting sites for slit-faced bats are diverse, and may include hollow trees, dense foliage, rocky outcrops, caves, buildings, ruins, abandoned wells, and porcupine and aardvark burrows.

Slit-faced bats have one offspring per year, typically at the beginning of the rainy season. Female large slit-faced bats leave their young behind in the roost when they set out at night to hunt. They return several times throughout the night to feed their young.

From the Greeks

The name Nycteris comes from the Greek word nykteros, meaning nocturnal.

SLIT-FACED BATS AND PEOPLE

There is no known special relationship between slit-faced bats and people.

CONSERVATION STATUS

The IUCN lists the Javan slit-faced bat and the Ja slit-faced bat as Vulnerable, facing a high risk of extinction in the wild. Three other species are listed as Near Threatened, not currently threatened, but may become so.

EGYPTIAN SLIT-FACED BAT (Nycteris thebaica): SPECIES ACCOUNT

Physical characteristics: A distinctive feature of the Egyptian slitfaced bat is its long ears. The bat has long, fine fur that is gray to red. Its underparts are lighter in color. These bats are also called common slit-faced bats. They are medium-size bats, with an adult weighing about 0.2 to 0.4 ounces (7 to 12 grams)—about the weight of five pennies.

Geographic range: Egyptian slit-faced bats are found in Africa.

Habitat: These bats live in the open savanna woodlands of sub-Saharan Africa, in the dry or arid (extremely dry) areas of Africa. These bats can live in a wide range of habitats, with roosts including caves, under mines, buildings, and tree hollows.

Diet: Egyptian slit-faced bats typically diet on arthropods, such as spiders, crickets, and scorpions, as well as insects, such as moths and beetles.

Behavior and reproduction: When foraging for food, Egyptian slit-faced bats pick their prey off the ground and vegetation surfaces, such as leaves or branches, as well as while flying. They can fly slowly and maneuver well, which allows them to hunt close to the ground and in dense vegetation.

These bats use echolocation and simply listening to detect their prey. Their large ears enable the bats to pick up sounds like the scuffling of some insects or the beating of wings. The purpose of the bird-like chirps they make while searching for their prey at night is unknown.

The roosts of Egyptian-slit faced bats include caves, areas under roads, mines, hollow trees, and roofs. They can be seen hanging from veranda (a structure like a porch) rooftops in temporary night roosts as they rest from their foraging. Observations have spotted colonies ranging in size from several and several hundred individuals.

Females produce a single offspring each year after gestating (being pregnant) for about 150 days. When the female leaves the roost at night to hunt, she takes her young with her and then sets them in another area while she hunts. Both sexes reach reproductive maturity at about their second year of life.

Egyptian-slit faced bats and people: There is no known significant relationship with people.

Conservation status: The IUCN does not consider Egyptian slitfaced bats to be threatened. ∎

FOR MORE INFORMATION

Books:

Fenton, M. Brock. Bats. New York: Checkmark Press, 2001.

Fenton, M. Brock. The Bat: Wings in the Night Sky. Buffalo, NY: Firefly Books, 1998.

Nowak, Ronald M. "Slit-faced Bats, or Hollow-faced Bats." Walker's Mammals of the World 5.1 Online. Baltimore: Johns Hopkins University Press, 1997. http://www.press.jhu.edu/books/walkers_mammals_of_the_world/chiroptera/chiroptera.nycteridae.nycteris.html (accessed on July 4, 2004).

Richardson, Phil. Bats. London: Whittet Books, 1985.

Ruff, Sue, and Don E. Wilson. Bats. New York: Benchmark Books, 2001.

Schober, Wilfried, and Eckard Grimmberger. The Bats of Europe and North America. Neptune City, NJ: T.F.H. Publications, Inc., 1997.

Periodicals:

Schnitzler, Hans-Ulrich, and Elisabeth K. V. Kalko. "Echolocation by Insect-Eating Bats." Bioscience (July 2001): 557.

Kerner, Sarah. "In the Bat Cave." Boys' Life (June 2003): 18.

Web sites:

Jacob, Davids. "Bats of the Western Cape." Cape Bat Action Team (Cape Bat). http://www.museums.org.za/sam/resources/mammal/bats.htm (accessed on July 4, 2004).

French, Barbara. "Where the Bats Are Part II: Other Animals' Shelters." Bat Conservation International, Inc. http://www.batcon.org/batsmag/v17n3-5.html (accessed on July 4, 2004).

Myers, Phil, and Bret Weinstein. "Family Nycteridae (slit-faced bats)." Animal Diversity Web.http://animaldiversity.ummz.umich.edu/site/accounts/information/Nycteridae.html (accessed on July 4, 2004).

Taylor, Peter. "Bats: Nature's Agricultural Allies" Science in Africa.http://www.scienceinafrica.co.za/2003/may/bats.htm (accessed on July 4, 2004).