The Egyptian free-tailed bat has fine, dense fur which is greyish-brown in colour, shading darker on the head and back and paler on the underparts, particularly around the throat. The wing are narrow and pointed with translucent light brown membranes, there is a short tail which is projects beyond the membrane connecting the wings and the ears sit close together on the top of the head and are rather rounded in shape. The face is rather bulldog-like and heavily wrinkled faces and this gives rise to the family name Molossidae, which refers to the Ancient Epirote mastiffs called molossus. Head and body length is 6–8 cm. Forearms 5 cm.
The Egyptian free-tailed bat is widely but apparently locally distributed throughout Africa, except parts of the north west and east through the Arabia and the Middle East to south Asia as far east as Bangladesh and south to Sri Lanka.
The Egyptian free-tailed bat occurs in a wide range of habitats, from arid savannas to humid uplands, so long as there is access to water both as a source of moisture for the bats and because the bats' insect food tends to congregate over and around water. It also requires cliff faces and in caves to roost in but it will also use man-made structures for roosting, such as old buildings and temples.
The Egyptian free-tailed bat is, like most bats, nocturnal and roost by day in colonies which can vary from as few as 3 to thousands of individual bats. It is a fast flier and in a night's foraging can cover large distances over open terrain. Prey is taken both in flight and plucked from the ground and includes beetles, caterpillars, flies, moths, spiders, termites alates and wasps. It is not as clumsy as other bat species on the ground and can scamper about quite adeptly.
Roost sites have a strong smell ad it is thought that this odour may be important in social interactions and with the bats being able to identify their roost sites. The female gives birth to one young each year, normally in the summer, and pregnancy lasts 4 months.
Molecular sequence data indicates T. aegyptiaca's closest relative is Chaerephon jobimena of Madagascar. These two species plus Tadarida brasiliensis of the Americas form a clade believed to be about 9.8 million years old.
Known as මහ දිව් රැළි-තොල් වවුලා (maeninag "greater wrinkled-lipped bat") in Sinhala.
Tadarida aegyptiaca, the Egyptian free-tailed bat, has an Old World distribution, stretching from Morocco across central and east Africa to southwest Asia, India, and Sri Lanka, excluding the Sahara desert. The range of T. aegyptiaca includes much of the African continent to South Africa.
This species has a patchy distribution throughout its range. It is poorly known through northwestern Africa, but in other parts of its range it is quite abundant and widespread, including India and South Africa.
Biogeographic Regions: palearctic (Native ); oriental (Native ); ethiopian (Native )
Tadarida aegyptiaca is sexually dimorphic, with males slightly smaller than females. Males range in size from 11.0 to 20.0 g, with an average of 15.8 g, while females range from 13.8 to 20.5 g, averaging 16.3 g. The snout is long and slightly upturned at the lip. Ears are very large (18 to 23 mm long) and forward-pointing. The tragus is square with an accessory appendage. These bats have a grayish-brown dorsal coat, with particularly dark areas on the back of the head and the back. Tadarida aegyptiaca shares only with Tadarida brasiliensis among Tadarida the distinct separation of the ears along the top of the head.
The wingspan of T. aegyptiaca averages 35.4 cm, while the wing area is 0.0130 m^2. The aspect ratio for the wings is 9.7, with a wing loading of 12.0 Nm^-2. Body length is 104 to 120 mm, tail length is 41 to 46 mm, and forearm lenth is 47 to 56 mm. The dental formula is 1/2, 1/1, 2/2, 3/3.
Range mass: 13.8 to 20.5 g.
Average mass: 16.3 g.
Range length: 104 to 120 mm.
Average wingspan: 35.4 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: female larger
Tadarida aegyptiaca is usually found in warm, semi-arid and arid regions. It is generally not found in forested or mountainous habitats.
Egyptian free-tailed bats prefer rock crevices and cliff faces for diurnal roosts. They nest in human structures as well, including the roofs of houses and churches. They are also known to roost in caves, crevices, and dead trees.
Range elevation: 500 (high) m.
Habitat Regions: temperate ; tropical ; terrestrial
Terrestrial Biomes: desert or dune ; savanna or grassland ; chaparral ; scrub forest
Other Habitat Features: urban ; suburban ; caves
Egyptian free-tailed bats are echolocating aerial insectivores. Equipped with high-aspect-ratio wings, the actively hunts airborne prey, possibly up to 500 m above ground. They hunt using a long (10-20 ms), narrow bandwidth (5-10 kHz) search-phase echolocation call centered around 14-18 kHz. Echolocation frequencies can range up to 26 kHz, while the highest energy frequency is about 18 kHz. Tadarida aegyptiaca is considered a fast, long-range aerial-hawking insectivore.
This species is known to consume insects of the orders Lepidoptera and Coleoptera. In a study of T. aegyptiaca in the Rajasthan desert of India (25-30ºN), Advani (1982) found a distinct seasonal variation in diet. During the winter (December through February at this latitude), the bats preferred Coleoptera, Orthoptera, Diptera, and Hymenoptera. Foods consumed in less quantities during the winter included Lepidoptera, Araneae, Neuroptera, and Dictyoptera. In the spring and summer, Coleoptera contributed to an even greater percentage of diet, nearly 40%. Orthoptera were also a major component of the diet, as was Lepidoptera. Isoptera and Hymenoptera made up a modest percent of the diet, while Dictyoptera, Diptera, and Odonata made only meager contributions. The monsoon season brought about drastic changes in dietary composition. Isoptera became the dominant food source, with Coleoptera, Hymenoptera, Lepidoptera, and Orthoptera contributing to most of the rest of the diet. Diptera and Neuroptera made minor contributions, and some plant material was found as well. In the post-monsoon period prior to winter (October and November), dietary preferences closely resembled those for the winter. Coleoptera and Hymenoptera predominated, while Orthoptera, Lepidoptera, Diptera, and Odonata all made significant contributions. Some Isoptera, Dictyoptera, Neuroptera, Araneae, and plant parts were also found.
Animal Foods: insects; terrestrial non-insect arthropods
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods)
Tadarida aegyptiaca is a common insectivore throughout much of its range. This species may also be a host to various viruses and other pathogens, including rabies.
Tadarida aegyptiaca makes up a small part of the diet of owls. Young in roosts may fall prey to snakes.
Anti-predator Adaptations: cryptic
Like all microchiropterans, Tadarida aegyptiaca depends on echolocation to some degree. Apart from navigation, T. aegyptiaca uses its echolocating abilities in active pursuit of insectivorous prey.
There is some evidence to suggest that Egyptian free-tailed bats have a well-developed olfactory sense. The number of perforations in the cribriform plate for this species is much higher than other members of Vespertilionoidea. The cribriform plate facilitates the targeting of olfactory receptor (OR) axons with their specific glomeruli, leading to the first synapse of OR neurons with the olfactory bulb. Therefore, a higher number of cribriform plate perforations should be correlated with greater olfactory acuity. Rather than foraging, social behavior may be the reason for such olfactory prowess. However, in their study of scent-dispersing hairs (osmetrichia) in pteropodid and molossid bats, Hickey and Fenton (1987) found distinct hair types present in scent dispersing regions of several Tadarida, but not for the Egyptian free-tailed bat.
Communication Channels: visual ; acoustic ; chemical
Perception Channels: visual ; tactile ; acoustic ; ultrasound ; echolocation ; chemical
Data for Tadarida aegyptiaca is lacking, but the lifespan for molossids in general averages about ten years, plus or minus about three years.
Status: wild: 10 years.
There is no available data on the specific mating systems found in Tadarida aegyptiaca. As Advani (1982:19) states, “little is known about the ecology, biology, and ethology of this species.”
Tadarida aegyptiaca is monoestrous and monotocous, and it breeds seasonally. Females are sexually mature during their first year, whereas males do not reach sexual maturity until their second year. In South Africa, spermatogenesis occurs in February. By July, over 90% of seminiferous tubules are in late spermatogenesis. Spermatozoa are released into the epididymes and stored in the caudal epididymis from July through September. The seminiferous tubules regress in August and September, becoming inactive from October to January. Late spermatogenesis produces associated increases in testis mass, diameter of seminiferous tubules, and height of seminiferous epithelium above the condition during spermatogenic inactivity.
The uterus of Egyptian free-tailed bats is bicornuate in sexually mature females. The right uterine horn and ovary are significantly larger than their corresponding structures on the left side of the body. Follicular development occurs in April. Both ovaries develop up to the secondary follicle; later stages (including Graadian follicles and the corpus luteum) develop only in the right ovary. During the development of these follicles, the uterine endometrium becomes increasingly vascularized.
Copulation, ovulation, and fertilization occur in August. Gestation lasts about four months; births occur in December. A second period of follicular development occurs between October and December but does not result in ovulation. Lactation continues through January; by February females are in anoestrus.
A somewhat different reproductive cycle is observed for this species in the northern hemisphere. In India, mating occurs for three weeks from the end of May to early June. Ovulation immediately follows copulation. Gestation lasts from 77 to 90 days. Pregnancy occurs from June through September, with births occurring through October.
Breeding interval: Tadarida aegyptiaca breeds once yearly.
Breeding season: Mating occurs between May and August, depending on latitude.
Average number of offspring: 1.
Range gestation period: 77 to 120 days.
Average weaning age: 1 months.
Range time to independence: 8 (high) months.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 2 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Parental investment prior to parturition is high in both sexes. Males generate and store sperm for up to six months, whereas females exhibit a very long period of gestation (up to four months). Because females only give birth to one individual each year, they are able to devote all post-parturition resources to that pup.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
Tadarida aegyptiaca is not listed on any threatened or endangered species lists.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Because this species is known to roost in buildings, guano deposits may cause some risk of contamination by bacteria, arthropods, and other pests. However, guano deposits are usually small and dry, so this risk is slight. There is also some risk of rabies from coming into contact with this species, like all bats. Additionally, the coarse-scale distributions of disease outbreaks of all four strains of African filovirus (including Marburg and Ebola) overlap with the range of T. aegyptiaca. A total of 38 genera and well over 100 species of small mammal share this overlap, and no work yet has been performed on Egyptian free-tailed bats to show that they serve as a host for Filoviridae viruses.
Negative Impacts: injures humans (causes disease in humans ); household pest
Egyptian free-tailed bats are geographically widespread consumer of potentially damaging pest animals such as Lepidoptera and Hymenoptera. They may thus serve to control populations of harmful insects in areas where they are abundant.
Positive Impacts: controls pest population
One subspecies, T. a. thomasi, occurs in abundance in the Great Indian Thar Desert. When referred to in the literature, this subspecies is also associated with the common name “wrinkle-lipped bat." In Egypt, the subspecies present is T. a. aegyptiaca.