Egyptian bat

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Egyptian bat
Rousettus egypticus.jpg

Egyptian bat ( Rousettus aegyptiacus )

Systematics
Superordinate : Laurasiatheria
Order : Bats (chiroptera)
Family : Fruit bats (Pteropodidae)
Tribe : Rosette bat (rousettini)
Genre : Cave Bat ( Rousettus )
Type : Egyptian bat
Scientific name
Rousettus aegyptiacus
( E. Geoffroy , 1810)

The Egyptian fruit bat ( Rousettus aegyptiacus ) is a fruit-eating Fledertier that the family of bats belongs. It is widespread in Africa and the Middle East as far as India.

Egyptian bats were first described in 1810 by the French naturalist and zoologist Etienne Geoffrey Saint-Hilaire. He discovered them in the pyramid of Cheops during Napoleon 's Egyptian campaign (Bergmans, 1994). According to the morphological systematics, Egyptian flying dogs belonged to the Chiroptera group, the suborder Megachiroptera, the family Pteropodidae, the subfamily Pteropodinae, the tribe Pteropodini, the genus Rousettus (Kwiecinski and Griffiths, 1999). However, recent molecular studies attribute this genus to the suborder Yinpterochiroptera and the superfamily Pteropodoidea (Ao et al., 2007).

Egyptian bats are medium-sized bats with a wingspan of up to 60 cm and a weight of 80–170 grams. The body length of the males varies between 14 and 19.2 cm, while the females are usually smaller (12.1–16.7 cm). The color of the back varies from dark brown to moderately gray. The fur on the belly is lighter in several shades (ash gray). Short fur covers the entire head up to the nose. Sexual dimorphism is not observed in color, but in males the long coat on the nape of the neck is more developed and has the appearance of a mane of rusty hue. Egyptian bats have a rather primitive and simple echolocation system. Their ears are small, black or dark brown, the tragus is not specialized like the representatives of the Yangochiroptera. The Egyptian bats have large eyes that are adapted to dusk and night vision. The color of the iris is brown.

Geographical distribution

Among the fruit bats, the Egyptian bat are the most widespread species. On the African continent they are located north of Angola and Nigeria , east of Mozambique , Kenya and Ethiopia . They occur in the Nile Valley to the coast of the Mediterranean, they are typical in the Middle East to Cyprus and in southern Turkey . In the east, their habitat includes Iran, Pakistan and India.

Conditions and habitats

Their wings are equally well pronounced in humid tropical climates as well as in arid regions between 0 and 4000 meters above sea level.

The animals stay in caves or in buildings that are inhabited by people during the day. Unlike most other carnivorous bats from the superfamily Pteropodoidea, the Egyptian bats do not settle on trees and open spaces. They live in colonies, the number of which varies from several to hundreds of individuals.

Their population is large, on average there are several hundred animals in the caves, but in some areas there are up to 3,000 individuals.

physiology

There are several subspecies that differ from one another, including shades of wool.

Egyptian bats have a two-horned uterus with a single vagina, so they have a double pregnancy. After the first egg cell has been fertilized in a horn of the uterus, a second fertilization with delayed embryo implantation takes place. If the first hatchling dies for any reason, the embryo from the other part of the uterus will actively develop. This fact has been established through observations on animals in captivity.

The body weight of the newborn is more than 20% of the weight of the mother. Compared to other mammals, this proportion is exceptionally high. The cubs of the Egyptian bat ( Rousettus aegyptiacus ) weigh 22.5 g on the second day of life and the mother weighs 127 g (17% of the mother's weight), as the zoologist Erwin Kulzer observed in 1966. The baby is born blind and helpless, but is able to reach the mother's nipple and suckle firmly. The time at which the eyes are opened varies from person to person. Some babies open their eyes on the first day, others only on the 9th day. The area of ​​the flight membrane is still small compared to adult animals, but in all other details the wing is already fully formed. Characteristic are the sizes of the first (big) finger on the wing and the legs with claws. For a newborn, this is vital when grasping. Up to two weeks, the baby hangs on the mother, clings to the wool with claws and holds the nipple tight.

nutrition

Your diet includes a variety of fruits (bananas, oranges, grapes, mangoes, apricots, peaches, apples, litchi fruits), flowers, pollen, rarely leaves.

After finding food, they go to a quiet place. The food is held with one hind paw when it is consumed. The animals lick each other diligently after each meal.

Reproduction

Egyptian bats mate year-round, but in some areas (with more temperate climates), seasonal reproduction in natural settings is observed. In captivity, the animals give birth to offspring synchronously. The frequency of such "waves" is about five months. The mating initiator is the male who grabs the female with his wings, pulls her towards him and grabs her neck with his teeth. Usually the female screams until copulation is complete.

Typically, the female gives birth to a single cub. In the Moscow Zoo there were no cases of the birth of two cubs of the winged Egyptian bat, however, the scientific literature mentions such events.

behavior

Typically the Egyptian bats leave their quarters an hour after sunset to look for food. You return around four in the morning. They sleep or doze until noon, tightly knotted together. Then they wake up and prepare for the night flight, they brush their wings and fur.

During the flight and the search for food, the animals use three sensory systems. The eyes of the Egyptian bat are just as well developed as other species of Pteropodidae, but the genus Rousettus is the only one of the Pteropodidae to have the ability to echolocalize so that they can fly in complete darkness. With the help of the tongue and the corners of the mouth, the animals generate a series of clicks that help with orientation. When searching for food, the sense of smell plays an important role. With it, the animal can not only recognize a fifty to one hundred milligram piece of banana in a twenty meter long corridor, but also assess the quality and ripeness of the fruit.

Postnatal development is similar in the genus Rousettus. Mothers carry their cubs with them all the time for the first 2-3 weeks. Then they leave the boys in the vaults of the cave only for a few minutes. With Rousettus, mother and child have almost constant contact for 30–40 days. Over time, the mother leaves her cub for longer and longer periods of time. The young animals, which are now gaining independence, begin to move in the colony after at least 25 days by actively using their wings. From 40–55 days after birth, R. leschenaulti tries to flutter short stretches clumsily in a straight line. R. Aegyptiacus's first flight at the age of 63-70 days always takes place during the day and is carried out via the mother. The female stops feeding milk to the young after 60–70 days and it switches to fruit. On the 100th day after birth, the young animals leave their mother's den. You stay close at first. They become completely independent after nine months, when they reach the height and weight of adults.

Enemies

The main enemy is man. Natural predators have not been described, but birds of prey such as hawks and cave predators such as snakes are likely. Their night life, their cave dwellings, their flight and camouflage colors help them to protect themselves from predators.

Ecosystem Role and Endangerment

Egyptian bats are pollinators for the plants they feed on.

Due to their fruit-eating diet, the Egyptian bats are often viewed as a threat to fruit crops during the growing season. Plantation owners and farmers often hunt the Egyptian bats to reduce the risk of crop damage and lost profits.

They are also used as food. As a result, their number is decreasing in some regions.

Security status

The Egyptian bat is not a protected species and belongs to the group of animals least threatened with extinction.

Web links

Commons : Egyptian Bat  - Collection of images, videos and audio files

Individual evidence

  1. ^ Wim Bergmans: Taxonomy and biogeography of African fruit bats (Mammalia, Megachiroptera). 4. The genus Rousettus Gray, 1821 . In: Beaufortia . tape 44 , no. 4 , 1994, ISSN  0067-4745 ( naturalis.nl [accessed January 8, 2018]).
  2. ^ Gary G. Kwiecinski, Thomas A. Griffiths: Rousettus egyptiacus . In: Mammalian Species . No. 611 , May 5, 1999, ISSN  0076-3519 , p. 1-9 , doi : 10.2307 / 3504411 ( oup.com [accessed January 8, 2018]).
  3. ↑ Lei Ao, Xiuguang Mao, Wenhui Nie, Xiaoming Gu, Qing Feng: Karyotypic evolution and phylogenetic relationships in the order Chiroptera as revealed by G-banding comparison and chromosome painting . In: Chromosome Research . tape 15 , no. 3 , April 1, 2007, ISSN  0967-3849 , p. 257–268 , doi : 10.1007 / s10577-007-1120-7 ( springer.com [accessed January 8, 2018]).
  4. ↑ Grzimek, B. (ed.): Grzimek's animal life encyclopedia . In: AGRIS: International Information System for the Agricultural Science and Technology . 1973 ( fao.org [accessed January 8, 2018]).
  5. ^ A b c Gary G. Kwiecinski, Thomas A. Griffiths: Rousettus egyptiacus . In: Mammalian Species . No. 611 , May 5, 1999, ISSN  0076-3519 , p. 1-9 , doi : 10.2307 / 3504411 ( oup.com [accessed January 8, 2018]).
  6. ↑ a b c d Kingdon, Jonathan .: East African mammals: an atlas of evolution in Africa . University of Chicago Press, Chicago 1984, ISBN 0-226-43719-1 .
  7. ↑ a b c d Erwin Kulzer: Physiological Ecology and Geographial Range in the Fruit-Eating cave Bat Genus Rousettus Gray, 1821 - A review, in: Bonner Zoologische Kollegen, Jg. 30 (3,4), December 1979. Retrieved on 31 May 2020 (UK English).
  8. ↑ Korine, C., Izhaki, I., Makin, D .: Population structure and emergence order in the fruit-bat (Rousettus aegyptiacus: Mammalia, Chiroptera) . In: Journal of Zoology, Lond. tape 232 , 1994 ( org.pl [accessed January 8, 2018]).
  9. ↑ B. Herzig-Straschil, GA Robinson: On the ecology of the fruit bat, rousettus aegyptiacus leachi (A. Smith, 1829) in the Tsitsikama Coastal National Park . In: Koedoe . tape 21 , no. 1 , March 9, 1978, ISSN  2071-0771 , p. 101–110 , doi : 10.4102 / koedoe.v21i1.965 ( koedoe.co.za [accessed January 8, 2018]).
  10. ↑ Craig S. Hood: Comparative morphology and evolution of the female reproductive tract in macroglossine bats (mammalia, chiroptera) . In: Journal of Morphology . tape 199 , no. 2 , February 1, 1989, ISSN  1097-4687 , p. 207–221 , doi : 10.1002 / jmor.1051990207 ( wiley.com [accessed January 8, 2018]).
  11. ↑ Е. И. Кожурина, О. Г. Ильченко: Тайны репродуктивной биологии летучих собак . In: Plecotus et al . No. 13 , 2010, ISSN  1606-9900 , p. 20–23 ( elibrary.ru [accessed January 8, 2018]).
  12. ↑ a b c Search Results - Biodiversity Heritage Library. Accessed January 8, 2018 .
  13. ↑ Erwin Kulzer: Studies on the biology of fruit bats of the genus Rousettus Gray . In: Journal for Morphology and Ecology of Animals . tape 47 , no. 4 , July 1, 1958, ISSN  0372-9389 , p. 374-402 , doi : 10.1007 / BF00407474 ( springer.com [accessed January 9, 2018]).
  14. ↑ Plecotus pars spec. (Contents). Retrieved January 9, 2018 .
  15. ^ DR Griffin, A. Novick, M. Kornfield: The sensitivity of echolocation in the fruit bat, rousettus . In: The Biological Bulletin . tape 115 , no. 1 , August 1, 1958, ISSN  0006-3185 , p. 107–113 , doi : 10.2307 / 1539097 ( uchicago.edu [accessed January 9, 2018]).
  16. ^ The evolution of echolocation in bats . In: Trends in Ecology & Evolution . tape 21 , no. 3 , March 1, 2006, ISSN  0169-5347 , p. 149–156 , doi : 10.1016 / j.tree.2006.01.001 ( sciencedirect.com [accessed January 9, 2018]).
  17. ^ A b F. P. Möhres, E. Kulzer: About the orientation of the fruit bats (Chiroptera - Pteropodidae) . In: Journal of Comparative Physiology . tape 38 , no. 1-2 , January 1, 1956, ISSN  0044-362X , p. 1–29 , doi : 10.1007 / BF00338621 ( springer.com [accessed January 9, 2018]).
  18. ↑ a b c V. Elangovan, H. Raghuram, E. Yuvana Satya Priya, G. Marimuthu: Postnatal growth, age estimation and development of foraging behavior in the fulvous fruit batRousettus leschenaulti . In: Journal of Biosciences . tape 27 , no. 7 , December 1, 2002, ISSN  0250-5991 , p. 695–702 , doi : 10.1007 / BF02708378 ( springer.com [accessed January 9, 2018]).
  19. ↑ FA Mutere: The breeding biology of the fruit bat Rousettus aegyptiacus E. Geoffroy living at o degrees 22'S. In: Acta tropica . tape 25 , no. 2 , 1968, ISSN  0001-706X ( europepmc.org [accessed January 9, 2018]).
  20. ^ A b c Marty S. Fujita, Merlin D. Tuttle: Flying Foxes (Chiroptera: Pteropodidae): Threatened Animals of Key Ecological and Economic Importance . In: Conservation Biology . tape 5 , no. 4 , December 1, 1991, ISSN  1523-1739 , pp. 455-463 , doi : 10.1111 / j.1523-1739.1991.tb00352.x ( wiley.com [accessed January 9, 2018]).