Little horse jumper
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Little horse jumper ( Allactaga elater ) in the zoological garden in Pilsen |
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| Allactaga elater | ||||||||||||
| ( Lichtenstein , 1828) |
The little horse diver ( Allactaga elater ) is a rodent from the genus of the horse diver ( Allactaga ). It occurs in arid regions over large parts of Asia from Turkey and Iran to Russia and in the north of the People's Republic of China and Mongolia .
features
The little horse jumper is the smallest species of the genus. It reaches a head and trunk length of 9.0 to 11.5 centimeters with a tail of 14.4 to 18.5 centimeters in length . The males reach a weight of 54 to 73 grams, the females weigh 44 to 59 grams a little less. The rear foot length is 46 to 55 millimeters, the ear length 29 to 39 millimeters. The animals are comparatively small, but have a very long tail, long ears and long hind feet. The fur on the back is dark to smoke gray, the sides of the body are yellowish and the neck, throat and belly are snow white. The tail has a black tail, but the tip itself is white and in most individuals the tail is divided on the back by a white line. The hind feet have five well-developed toes that are separated from each other and have comb-like structures. The front feet are significantly smaller and the claws significantly shorter than those of the Mongolian horse jumper ( Allactaga sibirica ). The long ears almost form a cylindrical tube.
| 1 | · | 0 | · | 1 | · | 3 | = 18 |
| 1 | · | 0 | · | 0 | · | 3 |
The skull has a total length of 25 to 29 millimeters. The nasal bones are about half as long as the bone seam between the frontal and parietal bones . Like all species of the genus have the animals in the upper jaw half per one to a incisor tooth formed incisor (incisor) to which a tooth gap ( diastema follows). This is followed by a premolar and three molars . In contrast, the animals do not have a premolar in the lower jaw. In total, the animals have a set of 18 teeth. The upper incisors are not clearly protruding and the diameter of the upper premolars is significantly smaller than that of the last molar.
distribution
The little horse jumper occurs in arid regions over large parts of Asia from the Caucasus , the far east of Turkey and Iran to the south of Siberia in the north of the People's Republic of China and Mongolia . He also lives in Afghanistan , Armenia , Azerbaijan , Georgia , Kazakhstan , Kyrgyzstan , Pakistan , Tajikistan , Turkmenistan and Uzbekistan . In the People's Republic of China, it is only found in the north of the Xinjiang Autonomous Region in the Djungarian Basin.
Way of life
The little horse jumper is largely nocturnal, but can also be found after sunrise and before sunset. It lives in different habitats in dry and sandy as well as rocky and loamy semi-desert areas as well as in steppe regions , but avoids the vegetation-free desert and the vegetation-rich areas. In general, the species prefers landscapes with bush vegetation, in addition it occurs in thin stocks of the salt-loving beach wormwood ( Artemisia maritima ). It also occurs in anthropogenically modified regions and on the edge of agricultural areas.
Like all species of the genus, the little horse jumper is adapted to rapid locomotion through long jumps and can reach speeds of up to 48 km / h. The species feeds mainly on underground and green parts of plants such as tubers, stems, leaves and seeds, plus insects. It lives as a loner and digs simple burrows that can reach flat under the ground or up to 60 centimeters deep with a maximum length of about 1.40 meters. The burrows are locked, there is little sputum in the entrance area, so they are difficult to find. There is a nest chamber in the center of the building. A total of four types of construction are known, which differ in their structure and which can be used in parallel. There is a summer and a winter building, as well as a building with a nest chamber for rearing young and temporary buildings. In addition to their legs and arms, the animals also use their incisors to dig in hard ground. In most of its range, the little horse jumper hibernates for four months from mid-November to mid-March.
The reproduction period extends from April to July, whereby the females can have one to three litters per year with two to eight young animals each. The first litters have an average of 4.5 young animals, the second 3.7. The males and some females reach sexual maturity after 3 to 3.5 months.
Systematics
The small horse diver is classified as an independent species within the genus of the horse diver ( Allactaga ), which consists of eleven species. The first scientific description comes from Martin Hinrich Lichtenstein from 1828, who described the species using individuals from western Kazakhstan.
Status, threat and protection
The Little Horse Jumper is classified as Least Concern by the International Union for Conservation of Nature and Natural Resources (IUCN). This is justified with the large distribution area and the assumed large global populations of the species. The populations are generally stable and the species is comparatively common in its distribution area. However, in some regions, especially north of the Caspian Sea , the population is declining. Here the declines are due to the conversion of habitats in steppe areas into agricultural areas or to the spread of desert areas ( desertification ). In Mongolia, stocks are declining due to the drying up of water sources and droughts. In Turkey, the species occurs in a small population in the semi-desert area, but the habitat is endangered due to irrigation.
Population fluctuations are typical for the species, so that the number of individuals of the animals can increase in individual years, although the populations are generally declining.
supporting documents
- ↑ a b c d e f g h i j Andrew T. Smith: Small Five-Toed Jerboa. In: Andrew T. Smith , Yan Xie: A Guide to the Mammals of China. Princeton University Press, Princeton NJ 2008, ISBN 978-0-691-09984-2 , pp. 200-201.
- ↑ Andrew T. Smith: Family Dipodidae / Subfamily Allactaginae. In: Andrew T. Smith , Yan Xie: A Guide to the Mammals of China. Princeton University Press, Princeton NJ 2008, ISBN 978-0-691-09984-2 , pp. 198-199.
- ↑ a b c d e f g h Allactaga elater in the IUCN Red List of Threatened Species 2014.3. Posted by: G. Shenbrot, K. Tsytsulina, N. Batsaikhan, D. Avirmed, D. Tinnin, G. Sukhchuluun, D. Lkhagvasuren, 2008. Retrieved August 9, 2015.
- ↑ Allactaga elater ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. . In: Don E. Wilson , DeeAnn M. Reeder (Eds.): Mammal Species of the World. A taxonomic and geographic Reference. 2 volumes. 3. Edition. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-8018-8221-4 .
literature
- Andrew T. Smith: Small Five-Toed Jerboa. In: Andrew T. Smith , Yan Xie: A Guide to the Mammals of China. Princeton University Press, Princeton NJ 2008, ISBN 978-0-691-09984-2 , pp. 200-201.
Web links
- Allactaga elater inthe IUCN Red List of Threatened Species 2014.3. Posted by: G. Shenbrot, K. Tsytsulina, N. Batsaikhan, D. Avirmed, D. Tinnin, G. Sukhchuluun, D. Lkhagvasuren, 2008. Retrieved August 9, 2015.