Nycteris thebaica
Egyptian slit-faced bat

Egyptian slit-faced bats are found throughout Africa and parts of southern Europe. They range from South Africa up through Egypt, the Arabian Peninsula, and to the island of Corfu. Nycteris thebaica is not found much outside of Africa and the Arabian Peninsula. (Corbet and Hill, 1991; Gray, Fenton, and Van Cakenberghe, 1999; Nowak, 1999; Reeder and Wilson, 1993)

This species is most often found in dry habitat types, such as savanna woodland areas. However, they are found in various other habitat types. (Gray, Fenton, and Van Cakenberghe, 1999; Nowak, 1999)

These bats use a wide variety of roost sites, including caves, mine tunnels, tombs, military bunkers, masonary fireplaces, buildings, ruins, culverts, abandoned wells, pit latrines, root cavities, rock crevices, hollow trees, dense foliage, rocky outcrops, and sometimes the burrows of porcupines or aardvarks. Often times they separate roost sites for night and day. The selection of such a site is dependent on where they can find cool temperatures. (Gray, Fenton, and Van Cakenberghe, 1999; Nowak, 1999)

Pelage tends to be long and silky, with a range of colors from gray, to light red, to murky brown, with a white to light grey stomach. Compared to other members of Nycteridae, this species has lighter pelage. Typically any animal that lives in dry habitats has a lighter pelage compared to those that live in wet habitats. (Gray, Fenton, and Van Cakenberghe, 1999; Nowak, 1999)

This species varies greatly in body mass from 6.5 to 16 grams, and the total body length ranges from 83 to 168 mm, with a wingspan of 270 to 307 mm. Females tend to be larger than males. These bats have enormous ears that are longer than their total head length. Surprisingly, they have a very small tragus in relation to the size of their ears. An extensive nose leaf is also present, with a split in the middle. In proportion to their body size, they have a long tail, which is totally enclosed in a membrane called the uropatagium. The tip of the tail and uropatagium forms the shape of a "T", which is a distinctive characteristic of the family Nycteridae.

The dental formula for this species is I 2/3, C 1/1, P 1/2, M 3/3 = 32. Incisors are chisel-like in shape, and molars are small. Their P4 is so small it is almost not visible because it is hidden by P2 and M1. These bats are diphyodont, meaning there are two sets of teeth, one set of milk teeth, and another set of adult teeth. Nycteris thebaica is unique from other bats in that it retains its milk teeth outside of the womb. It is not uncommon for their milk teeth to be present for a short period of time with their first adult teeth. (Gray, Fenton, and Van Cakenberghe, 1999; Nowak, 1999)

There is little information about the lifespan and longevity of this species other than observations of those that have been kept in captivity.

Egyptian slit-faced bats do not do well in captivity. When given food and water they will eat the food, but will not touch the water, and as a result it is not uncommon for them to die of dehydration.

It is likely that individuals of this species live for many years, as most microchiropterans are long lived. (Gray, Fenton, and Van Cakenberghe, 1999; Nowak, 1999)

The majority of species in Nycteris live in either small groups or pairs. However, this species has been seen in colonies of as many as 500 to 600 individuals (with some reports estimating thousands of animals) in a single cave. Populations in South Africa have inhabited caves with other species of bats such as Myotis tricolor, Miniopterus schreibersii, Miniopterus fraterculus, Hipposideros caffer, Rhinolophus simulator, Rhinolophus clivosus, and Rhinolophus blasii. In Eastern Africa, these bats live in caves with Rousettus aegyptiacus and Taphozous perforatus. Mixed species groups of lactating females are known to roost in caves together, for example, in Egypt, N. thebaica, Asellia tridens, and Taphozous perforatus were all found together. (Gray, Fenton, and Van Cakenberghe, 1999; Nowak, 1999)

These bats hang upside down from trees and other roosting sites. They attach themselves by their hind legs to the tree or cave with their heads positioned towards their backs.

This species is known to be migratory, but there is little information on the reasons for migration. It has been hypothesized that migration occurs as a result of resource availability. (Gray, Fenton, and Van Cakenberghe, 1999)

Home Range

There is little available information about the home range of this species.

These bats, like most other bats, use echolocation for finding prey. However, like other gleaning bats, their echolocation calls are not strong and as a result this species is often called a “whispering” bat. The echolocation that they produce has low intensity, and is multi-harmonic. Echolocation is used when they are assessing the area around them, especially for prey location.

This species uses eyesight more than some bats, probably as compensation for its weak echolocation ability.

In addition to calls used for echolocation, researchers have identified two long tonal calls made by these bats. One is made in a roost and appears to attract other bats to the source of the call. The other call is made when bats leave the roost.

As in other mammals, tactile and chemical communication probably play some role in mating and parental care. (Gray, Fenton, and Van Cakenberghe, 1999)

The diet of these bats is variable and dependent on geographic location and season.

This species eats a mixture of lepidopterans (butterflies and moths). They also feed on other insects and spiders. A major portion of their diet consists of scorpions when available. Other key components of their diet include: orthopterans and coleopterans. There are also numerous prey organisms that are only a minor part of their diet, such as: araneidans, dipterans, hemipterans, homopterans, hymenopterans, isopterans, and neuropterans. (Gray, Fenton, and Van Cakenberghe, 1999; Nowak, 1999)

The feeding habits vary. Nycteris thebaica preys on organisms while flying, or observes them while hanging upside down from a tree and then goes after the prey. As these bats hang from a tree, they observe the surrounding area for prey. Their enormous ears are used to detect any noise made by potential prey. Once it hears a potential prey item, an individual bat will go after the area where the sound came from. In addition to their ears, they use their eyes (since echolocation is weak for these bats) to locate their prey.

This species also preys on insects that are not moving, such as on the ground, walls, rocks, lights, and vegetation. Small prey will be eaten on the spot, but larger prey will be taken to a tree and eaten while the bat is hanging. Their uropatagium is a tool that they use to bring their prey to their mouth. The females leave the roost at dusk (with their young) to go on regular hunts for food. (Gray, Fenton, and Van Cakenberghe, 1999)

There is little available information on predation of this species. It is possible that they are prey to snakes as well as to some birds, including bat hawks, Machaerhamphus alcinus. Many members of the genus Nycteris asre reported to flutter around roosts, which could make them vulnerable to small mammals as well.

When the young are unable to fly, females take their young with them when they go hunting, as a way to avoid predators. (Gray, Fenton, and Van Cakenberghe, 1999; Nowak, 1999)

As predators, these bats are likely to have some impact on insect populations. As prey, they may have a positive effect on their predators. In addition, N. thebaica is host for many parasites, including helminths, nematodes, trematodes, and standard mammalian ectoparasites. Mites infecting the margins of the ears are common in this species, and can cause individuals to damage their membranes from scratching. These bats may be an important reservoir host for nematode larvae in the suborder Spirurata, since these neoatodes use insects--the prey of the bats-- as intermediate hosts. (Gray, Fenton, and Van Cakenberghe, 1999)

There are no known adverse effects of this species on humans.

There is no known positive economic importance of this species for humans.

There is little available information on the conservation status of N. thebaica. No information was found on either the IUCN Red List or CITES. These bats are not located in the United States and therefore are not found on the US Federal List.

There are no fossil specimens discovered of this species. (Nowak, 1999)