Animal Diversity Web

Ge­o­graphic Range

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). (Grz­imek, 2003; No­gales, et al., 2006; Nowak, 1999)

• Biogeographic Regions
• palearctic
  • native
• ethiopian
  • native

Habi­tat

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). (Kwiecin­ski and Grif­fiths, 1999)

• Habitat Regions
• tropical
• terrestrial

• Terrestrial Biomes
• savanna or grassland
• forest
• rainforest
• scrub forest

• Other Habitat Features
• caves

• Range elevation

  0 to 4000 m

  0.00 to 13123.36 ft

Phys­i­cal De­scrip­tion

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). (Grz­imek, 2003; Kwiecin­ski and Grif­fiths, 1999)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• male larger

• Range mass

  80 to 170 g

  2.82 to 5.99 oz

• Range length

  12.1 to 19.2 cm

  4.76 to 7.56 in

• Average wingspan

  60 cm

  23.62 in

Re­pro­duc­tion

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). (Bay­demir and Al­bayrak, 2006; Bernard and Cum­ming, 1997; 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). ("Egypt­ian Fruit Bat", 2006; Ko­rine, et al., 1994; Kwiecin­ski and Grif­fiths, 1999; Okia, 1987)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous

• 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

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). (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

Lifes­pan/Longevity

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). (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

Be­hav­ior

Egypt­ian rousettes are found in groups of var­i­ous sizes, rang­ing from small colonies of 20 to 40 mem­bers to large colonies of 9,000. These colonies pre­fer to roost dur­ing the day in dark, slightly humid en­vi­ron­ments such as cave sys­tems and ruins, though small colonies have been seen roost­ing in trees (Grz­imek, 2003). Dur­ing breed­ing sea­sons, males and fe­males sep­a­rate; males form­ing bach­e­lor groups and fe­males form­ing ma­ter­nity colonies. Egypt­ian rousettes roost in close con­tact with other mem­bers of the colony to re­duce the in­flu­ence of tem­per­a­ture fluc­tu­a­tions. Close con­tact among mem­bers of the colony also al­lows com­mu­ni­ca­tion with each other through­out the day dur­ing roost­ing. Egypt­ian rousettes are more ac­tive dur­ing the late af­ter­noon and into the night, when groom­ing is more fre­quent (Kwiecin­ski and Grif­fiths, 1999). In­di­vid­u­als leave the day roost close to sun­set each evening to for­age, re­turn­ing be­fore sun­rise. Dur­ing sum­mer months longer daylength de­lays emer­gence from the roost, sug­gest­ing a cir­ca­dian rhythm syn­chro­nized to light-dark cy­cles. Due to the change in light in­ten­sity, Egypt­ian rousettes have dif­fer­ent pat­terns of ac­tiv­ity be­tween sum­mer and win­ter sea­sons. Sum­mer sea­sons are char­ac­ter­ized by longer feed­ing in­ter­vals than win­ter sea­sons, de­spite re­duced dark pe­ri­ods and de­layed roost emer­gence (Kwiecin­ski and Grif­fiths, 1999). (Grz­imek, 2003; Kwiecin­ski and Grif­fiths, 1999)

• Key Behaviors
• troglophilic
• flies
• nocturnal
• motile
• migratory
• sedentary
• territorial
• social
• colonial

Home Range

Home range varies in Rouset­tus ae­gyp­ti­a­cus. This species has been noted to mi­grate south­ward in the north­ern re­gions of their ge­o­graphic range and for­age great dis­tances away from day roosts. Males ap­pear to de­fend ter­ri­to­ries, but their size has not been char­ac­ter­ized (Kwiecin­ski and Grif­fiths, 1999). (Kwiecin­ski and Grif­fiths, 1999)

Com­mu­ni­ca­tion and Per­cep­tion

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). (Hol­land and Wa­ters, 2007; Hol­land, et al., 2004; Roberts, 1975)

• Communication Channels
• visual
• acoustic
• chemical

• Perception Channels
• visual
• tactile
• echolocation
• chemical

Food Habits

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). (Grz­imek, 2003; Ko­rine, et al., 1996; Kwiecin­ski and Grif­fiths, 1999)

• Primary Diet
• herbivore
  • frugivore

• Plant Foods
• fruit

Pre­da­tion

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. (Fu­jita and Tut­tle, 1991)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • humans (Homo sapiens)

Ecosys­tem Roles

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). (Fu­jita and Tut­tle, 1991; Kwiecin­ski and Grif­fiths, 1999)

• Ecosystem Impact
• disperses seeds
• pollinates

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

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). (Fu­jita and Tut­tle, 1991; Izhaki, et al., 1995)

• Positive Impacts
• food
• pollinates crops

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

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). (Al­bayrak, et al., 2008)

Con­ser­va­tion Sta­tus

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). (Al­bayrak, et al., 2008)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Con­trib­u­tors

Rachel Cohen (au­thor), Rad­ford Uni­ver­sity, Karen Pow­ers (ed­i­tor), Rad­ford Uni­ver­sity, Tanya Dewey (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

2006. "Egypt­ian Fruit Bat" (On-line). Rosa­mond Gif­ford Zoo. Ac­cessed April 20, 2010 at http://​www.​rosamondgiffordzoo.​org/​assets/​uploads/​animals/​pdf/​EgyptianFruitBat.​pdf.

Al­bayrak, I., N. Asan, T. Yorul­maz. 2008. The Nat­ural His­tory of the Egypt­ian Fruit Bat, Rouset­tus ae­gyp­ti­a­cus, in Turkey (Mam­malia: Chi­roptera). Turk­ish Jour­nal of Zo­ol­ogy, 32: 11-18.

Bay­demir, N., I. Al­bayrak. 2006. A Study on the Breed­ing Bi­ol­ogy of Some Bat Species in Turkey (Mam­malia: Chi­roptera). Turk­ish Jour­nal of Zo­ol­ogy, 30: 103-110.

Bernard, R., G. Cum­ming. 1997. African Bats: Evo­lu­tion of Re­pro­duc­tive Pat­terns and De­lays. The Quar­terly Re­view of Bi­ol­ogy, 72: 253-274.

Fu­jita, M., M. Tut­tle. 1991. Fly­ing Foxes (Chi­roptera: Pteropo­di­dae): Threat­ened An­i­mals of Key Eco­log­i­cal and Eco­nomic Im­por­tance. Con­ser­va­tion Bi­ol­ogy, 5: 455-463.

Grz­imek, B. 2003. Grz­imek's An­i­mal Life En­cy­clo­pe­dia. Farm­ing Hills, Michi­gan: Gale Vir­tual Li­brary.

Hol­land, R., D. Wa­ters. 2007. The Ef­fect of Fa­mil­iar­ity on Echolo­ca­tion in the Megachi­ropteran Bat Rouset­tus ae­gyp­ti­a­cus. Be­hav­ior, 144: 1053-1064.

Hol­land, R., D. Wa­ters, J. Rayner. 2004. Echolo­ca­tion Sig­nal Struc­ture in the Megachi­ropteran Bat Rouset­tus ae­gyp­ti­a­cus Ge­of­frey 1810. The Jour­nal of Ex­per­i­men­tal Bi­ol­ogy, 207: 4361-4369.

Izhaki, I., C. Ko­rine, Z. Arad. 1995. The Ef­fect of Bat (Rouset­tus ae­gyp­ti­a­cus) Dis­per­sal on Seed Ger­mi­na­tion in East­ern Mediter­ranean Habi­tats. Oe­colo­gia, 101: 335-342.

Ko­rine, C., Z. Arad, A. Arieli. 1996. Ni­tro­gen and En­ergy Bal­ance of the Fruit Bat Rouset­tus ae­gypt­la­cus on Nat­ural Fruit Diets. Phys­i­o­log­i­cal Zo­ol­ogy, 69: 618-634.

Ko­rine, C., I. Izhaki, D. Makin. 1994. Pop­u­la­tion Struc­ture and Emer­gence Order in the Fruit-bat (Rouset­tus aeyyp­ti­a­cus: Mam­malia, Chi­roptera). The Zo­o­log­i­cal So­ci­ety of Lon­don, 232: 163-174.

Kwiecin­ski, G., T. Grif­fiths. 1999. Rouset­tus egyp­ti­a­cus. Mam­malian Species, 611: 1-9.

No­gales, M., J. Ro­driguez-Lu­engo, P. Mar­rero. 2006. Eco­log­i­cal Ef­fects and Dis­tri­b­u­tion of In­va­sive Non-Na­tive Mam­mals on the Ca­nary Is­lands. Mam­mal Re­view, 36: 49-65.

Nowak, R. 1999. Walker's mam­mals of the world. Bal­ti­more: John Hp­kins Uni­ver­sity Press.

Okia, N. 1987. Re­pro­duc­tive Cy­cles of East African Bats. Jour­nal of Mam­mal­ogy, 68: 138-141.

Roberts, L. 1975. Con­fir­ma­tion of the Echolo­ca­tion Pulse Pro­duc­tion Mech­a­nism of Rouset­tus. Jour­nal of Mam­mal­ogy, 56: 218-220.