Egyptian rousettes are one of 3 members of the Rousettus genus to use both visual orientation and echolocation. Echolocation in this species is produced through a series of crude, short clicks of the tongue against the side of the mouth (Roberts, 1975; Holland et al., 2004). These short, impulsive-paired clicks assist in navigation in the dark. The frequency range is usually 12 to 70 kHz, with click structure and duration most similar to dolphins. This form of echolocation has evolved independently from the echolocation system used by other echolocating bats, such as vespertilionids (Roberts, 1975; Holland et al., 2004; Holland and Waters, 2007).
Communication Channels: visual ; acoustic ; chemical
Perception Channels: visual ; tactile ; echolocation ; chemical
Rousettus aegyptiacus is considered a species of least concern by the IUCN. However, due to poaching and a negative interactions with commercial farming, there has been a decline in roosting sites (Albayrak et al., 2008).
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
Rousettus aegyptiacus is perceived by many fruit farmers to be a pest of fruit crops grown commercially for human production throughout its range, though little evidence supports this and cases are often exaggerated (Albayrak et al., 2008).
Throughout their range, Egyptian rousettes pollinate many commercially valuable fruit trees. This species also works to disperse seeds away from the parent plant, allowing seed germination and spread in unpredictable conditions (Fujita and Tuttle, 1991; Izhaki et al., 1995).
Positive Impacts: food ; pollinates crops
Egyptian rousettes are pollinators of many nocturnally flowering trees throughout paleotropical forests. Due to their frugivorous diets, they not only pollinate the flowers of fruit trees but also assist as the primary agent in seed dispersal for many tree species (Fujita and Tuttle, 1991). Egyptian rousettes are carriers for both ectoparasites and endoparasites throughout their geographic range. Ectoparasites that use Egyptian rousettes as hosts include: Spinturnix lateralis, Ancystropus leleupi, Ancystropus zelebori, Ancystropus lateralis, Ancystropus zeleborii, Liponyssus glutinosus, Liponyssus longimanus, Eucampsipoda africanum, Nycteribosca africana, Brachytarsina alluaudi, Eucampsipoda hyrtlii, Nycteribosca diversa, Thaumapsylla brevicep, Nycteribia pedicularia, Nycteribia schmidlii, Eucampsipoda africana, Afrocimex leleupi, Thaumapsylla breviceps, Archaeopsylla metallescens, and Alectorobius camicasi (Kwiecinski and Griffiths, 1999). Endoparasites that are found in Rousettus aegyptiacus include the hemosporidian Plasmodium roussetti and the roundworm Nycteridocoptes rousetti. Outbreaks of rabies are also found in populations of Egyptian fruit bats (Kwiecinski and Griffiths, 1999).
Ecosystem Impact: disperses seeds; pollinates
Mutualist Species:
Commensal/Parasitic Species:
Egyptian rousettes are frugivores, preferring to eat the pulp and juice of very ripe fruit. They typically take fruit from trees, such as lilac, mulberry, carob, sycamore, fig, and baobob (Kwiecinski and Griffiths, 1999; Korine et al., 1996; Grzimek, 2003). Egyptian rousettes consume 50 to 150% of total body mass in fruit each night. After selecting fruit, Egyptian rousettes take their fruit and roost close to the feeding tree. Only the pulp and juice is consumed; after thorough chewing, the seeds are spit out. Egyptian rousettes feed while holding the fruit close to the body, as a means of protecting the fruit from being pilfered by other bats. Stealing fruit is common, and these bats are aggressive when feeding (Kwiecinski and Griffiths, 1999).
Plant Foods: fruit
Primary Diet: herbivore (Frugivore )
Rousettus aegyptiacus is found throughout Africa south of the Sahara, in Egypt, and on the coastlines of the Arabian Peninsula (Grzimek, 2003). Egyptian rousettes are most common from latitudes 15 degrees north through 37 degrees south. However, they have been found as far as 40 degrees north in southern Turkey. They are also found on each of the Canary Islands, western North Africa, and throughout the Gulf of Guinea (Nogales et al., 2006; Nowak, 1999).
Biogeographic Regions: palearctic (Native ); ethiopian (Native )
Egyptian rousettes are found throughout Africa’s tropical rain forests, tropical deciduous forests, savanna, and Turkey’s Mediterranean scrub forests. Egyptian rousettes have been found in arid biomes; however, they prefer to remain in habitats that provide forest cover, roosting opportunities, and abundant fruit tree growth (Kwiecinski and Griffiths, 1999).
Range elevation: 0 to 4000 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: savanna or grassland ; forest ; rainforest ; scrub forest
Other Habitat Features: caves
The recorded maximum lifespan of Rousettus aegyptiacus is 22 years in the wild, with a maximum of 25 years in captivity for both males and females. In wild populations, average lifespan is typically 8 to 10 years due to factors such as predation, vitamin D deficiency, calcium-phosphorus imbalance, and osteoproliferation. Longevity in captive bats is also dependent on environmental temperatures and neurological impairment (Kwiecinski and Griffiths, 1999).
Average lifespan
Status: wild: 9 years.
Range lifespan
Status: captivity: 25 (high) years.
Average lifespan
Status: captivity: 22 years.
Typical lifespan
Status: wild: 8 to 10 years.
Typical lifespan
Status: captivity: 25 (high) years.
Average lifespan
Status: captivity: 22 years.
Egyptian rousettes are medium sized bats with dorsal pelage ranging from dark brown to medium gray. Ventral pelage in both genders is several shades lighter than dorsal coloration, with a collar of pale yellow or orange fur often seen around the neck. There is no color difference between genders; however, males have well-developed stiff hairs along the throat that are more recognizable than in females (Kwiecinski and Griffiths, 1999). Short fur completely covers the head almost to the end of the muzzle, with the exception of the forehead, where the fur is slightly longer. Ears are around the length of the muzzle, with blunt tips and dark coloration when compared to dorsal pelage. Egyptian fruit bats have large eyes adapted for twilight and night vision. Wing membranes are dark brown with short fur extending to the proximal half of the forearm. A claw is present on both the first and second digits, while all other digits have cartilage. Egyptian rousettes have five toes on both hind limbs, each with claws (Kwiecinski and Griffiths, 1999).
Males are typically larger than females with a total body length ranging from 14 to 19.2 cm, while females range from 12.1 to 16.7 cm. Adults may weigh 80 to 170 g and have a wingspan close to 60 cm. The forearm varies between 85 to 101.9 mm in males and 88.1 to 99 mm in females (Kwiecinski and Griffiths, 1999; Grzimek, 2003).
Range mass: 80 to 170 g.
Range length: 12.1 to 19.2 cm.
Average wingspan: 60 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger
Because of their frugivorous diet, Egyptian rousettes are sometimes considered a threat to fruit crops during the growing season. Plantation owners and farmers often hunt Egyptian rousettes or hire bounty hunters during the flowering and fruiting seasons to reduce the risk of crop damage and profit loss (Fujita and Tuttle, 1991). Egyptian rousettes, like many members of the Family Pteropodidae, are hunted for meat as well. As a result roost population densities have declined (Fujita and Tuttle, 1991). Natural predators have not been described but are likely to include aerial predators, such as falcons, and cave predators, such as snakes and mustelids. Their nocturnal habits, cave roosting, flight, and cryptic coloration all help them to avoid predation.
Known Predators:
Anti-predator Adaptations: cryptic
Rousettus aegyptiacus is a polygamous species, with biannual breeding seasons. However, instances of monoestry have been recorded at higher latitudes (Baydemir and Albayrak, 2006; Bernard and Cumming, 1997). Egyptian rousettes observed in latitudes south of Egypt have two distinct peak breeding seasons separated by short periods. The first peak breeding season is from spring through summer, the second is fall through winter. Births occur towards the end of each breeding season (Okia, 1987).
Mating System: polygynandrous (promiscuous)
Females give birth to and raise a single pup with each breeding effort, though twins have been recorded occasionally (Korine et al., 1994). Estimated gestation length is 3.5 to 4 months, with synchronized births occurring in breeding colonies (Kwiecinski and Griffiths, 1999; Okia, 1987). Newborn bats are born with deciduous teeth and are altricial - completely naked apart from a thin layer of down along the head and back. Pups are weaned at 6 to 10 weeks with no difference in growth between sexes. Young reach full adult weight and size around 9 months old, about the same time young become independent from their mothers (Kwiecinski and Griffiths, 1999). Sexual maturity is reached on average at 15 months, however, females have been noted to be sexually mature at 5 to 7 months ("Egyptian Fruit Bat", 2006).
Breeding interval: Breeding occurs twice yearly throughout most of their range, although one breeding effort per season may occur in northern latitudes.
Breeding season: Breeding occurs typically from April to August and October to February
Range number of offspring: 1 to 2.
Average number of offspring: 1.
Range gestation period: 3.5 to 4 months.
Average gestation period: 4 months.
Range weaning age: 6 to 10 weeks.
Range time to independence: 8 to 9 months.
Average time to independence: 9 months.
Range age at sexual or reproductive maturity (female): 5 to 16 months.
Average age at sexual or reproductive maturity (female): 15 months.
Range age at sexual or reproductive maturity (male): 14 to 18 months.
Average age at sexual or reproductive maturity (male): 15 months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
After birth Egyptian rousette pups are cared for solely by their mothers for around 9 months. They are capable of flying at 63 to 70 days after birth and stay with their mother until they have reached adult weight and size. Once mature, males leave maternity colonies to join bachelor groups, females join maternity colonies (Kwiecinski and Griffiths, 1999).
Parental Investment: altricial ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
