Cape short-tailed gerbil
| Cape short-tailed gerbil | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Cape short-tailed gerbil ( Desmodillus auricularis ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name of the genus | ||||||||||||
| Desmodillus | ||||||||||||
| Thomas & Schwann , 1904 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Desmodillus auricularis | ||||||||||||
| ( Smith , 1834) | ||||||||||||
The Cape short-tailed gerbil ( Desmodillus auricularis ) is a rodent of the long -tailed mouse ( Muridae) within the subfamily of gerbils and the only species of their genus.
features
The Cape short-tailed gerbil reaches a head-body length of 8.6 to 12.9 centimeters, a tail length of 7 to 10 centimeters and a weight between 30 and 82 grams. The females weigh on average about 20% less than the males. The rear foot measures 21 to 29 millimeters, the ear length is 10 to 14 millimeters.
The body is short and stocky, in its physique the Cape short-tailed gerbil corresponds to the other gerbils. The color of the fur on the back is variable and ranges from light brown to orange. The individual hairs are slate gray at the base, yellow-ocher in the middle and have a dark tip. The underside with the chin, throat and stomach as well as the limbs are white. The females each have two pairs of teats in the groin and in the construction region, a total of 8 teats. There is a noticeable white spot behind each ear, and there are other small spots above and below the eye. The head is large with a thickened nose, long black vibrissae and large eyes. The ears are small, oval, and flesh-colored. The front and rear legs are short and thick and have white hair on the top. The front foot has four fingers, the rear foot has five toes and hairy soles. With about 75 to 80% of the head-trunk length, the tail is of moderate length. It is well haired and in darker individuals it has a black tip, but does not wear a tassel and has no drawn out point (“pencil”).
The skull has a total length of 34.2 to 38.1 millimeters and a width of 18.7 to 22.3 millimeters. It is characterized by very strong, enlarged tympanic bladders (bullae tympanicae) that protrude beyond the occiput . In their length they correspond to about 41% of the skull length and are therefore larger in relation to this than in all other gerbils. The genome has a diploid chromosome set of 2n = 52.
Similar species, with which there is a risk of confusion, are the representatives of the Namib gerbils ( Gerbillurus ), which also live in southern Africa. Compared to these, the Cape short-tailed gerbil is slightly larger with a shorter tail, both in absolute terms and in relation to head-to-body length. The Namib gerbils also have an extended tail tip and a significantly smaller ear region with a tympanic bladder that is only about 30% of the length of the skull.
Distribution area and habitat
The Cape short-tailed gerbil is widespread in the arid and semi-arid regions of southwest Africa, especially in the Namib , Karoo and Kalahari . The distribution area extends from southwestern Angola across most of Namibia and Botswana to South Africa . The altitude distribution extends to about 1600 meters.
The Cape short-tailed gerbil can be found in the lowlands in sandy desert and semi-desert regions with sparse grass and shrubbery as well as on agricultural areas. Dense grass and bushes are avoided.
Way of life
It is mainly active at night and digs underground burrows that are more simply constructed than other gerbils, but also consist of a complex system of corridors with one to seven exits, dead ends and pantries. The burrows reach a depth of about 30 to 60 centimeters, the tunnels have a diameter of about 53 millimeters.
nutrition
The species is omnivorous , the diet mainly consists of seeds and insects . The food composition in winter consists mainly of seeds, in summer insects and green leaves predominate. In order to search for food, the animals move a maximum of about 30 meters from their burrows and they store supplies both within their burrows and in the vicinity. This behavior is also shown by individuals in human care. The water intake occurs through food, so the animals are not dependent on separate water intake. They can also store fat in the tail if enough food is available.
Social behavior and reproduction
Outside of the breeding season, the animals live solitary and alone in their burrows, even if the entrances are sometimes close together or the tunnels can be connected to one another. They are territorial and defend their territories; Animals kept together in a fenced-off area fought each other to the point of death. In captivity, the females are dominant over the males and can even kill and eat them, they only tolerate the males during the mating season.
The mating seasons are presumably distributed over the whole year, but the births take place almost exclusively during wet phases. Depending on the environmental conditions, the pregnancy lasts 21 to 35 days, then the female usually gives birth to 2 to 4 young, up to 7 have been registered. The young animals weigh around 1.8 to 4.4 grams at birth, are initially blind and open their eyes after around three weeks. After about a month they will no longer be suckled.
Predators and parasites
The main predators of the gerbils are owls, especially the barn owl ( Tyto alba ) and the spotted owl ( Bubo africanus ), and snakes like the cape cobra ( Naja nivea ). In addition, at least 24 species of fleas , mites and ticks have been identified as ectoparasites for the species, including some species that also play a role as disease vectors for humans.
Systematics
The Cape short-tailed gerbil is classified as an independent species in the ( monotypical ) genus Desmodillus, which only consists of it . The first scientific description comes from Andrew Smith from 1834, who described it as a type of real gerbil ( Gerbillus ) using individuals from the Kamiesberg region in the Namakwa district in South Africa . Oldfield Thomas and Harold Schwann established the independent genus Desmodillus in 1904 with the Cape short-tailed gerbil as a type .
No subspecies are described within the species.
Stocks, exposure and protection
The Cape short-tailed gerbil is represented in high numbers in its habitat. In the southwestern Kalahari the populations of the species amount to about 5 to 5.5% of the registered small mammals, whereby the occurrences are mainly in suitable microhabitats . Major fluctuations in the number of stocks rarely occur.
The species is classified by the International Union for Conservation of Nature and Natural Resources (IUCN) as “least concern” due to its very large distribution area and the assumed large population . It is unlikely that stocks will shrink so rapidly that they are classified in a hazard category. There are no existential risks.
literature
- Desmodillus auricularis, Cape Short-tailed Gerbil (Namaqua Gerbil). In: David CD Happold (Ed.): Mammals of Africa. Volume III: Rodents, Hares and Rabbits. Bloomsbury Publishing, London a. a. 2013; Pp. 267-268. ISBN 978-1-4081-2253-2 .
- Ronald M. Nowak: Walker's Mammals of the World. 2 volumes. 6th edition. Johns Hopkins University Press, Baltimore MD et al. 1999, ISBN 0-8018-5789-9 .
Web links
Individual evidence
- ↑ a b c d Don E. Wilson , DeeAnn M. Reeder (Ed.): Mammal Species of the World . A taxonomic and geographic Reference . 3. Edition. 2 volumes. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-8018-8221-4 (English, Desmodillus , Desmodillus auricularis ).
- ↑ a b c d e f g h i j k l m n Desmodillus auricularis, Cape Short-tailed Gerbil (Namaqua Gerbil). In: David CD Happold (Ed.): Mammals of Africa. Volume III: Rodents, Hares and Rabbits. Bloomsbury Publishing, London a. a. 2013; Pp. 267-268. ISBN 978-1-4081-2253-2 .
- ↑ Genus Desmodillus, Cape Short-tailed Gerbil. In: David CD Happold (Ed.): Mammals of Africa. Volume III: Rodents, Hares and Rabbits. Bloomsbury Publishing, London a. a. 2013; P. 266. ISBN 978-1-4081-2253-2 .
- ↑ a b c Desmodillus auricularis in the IUCN Red List of Threatened Species 2014.3. Posted by: N. Coetzee, 2008. Retrieved April 24, 2015.
- ↑ a b c d e f Ronald M. Nowak: Walker's Mammals of the World. 2 volumes. 6th edition. 1999, pp. 1451-1452.