Kusurats
| Kusurats | ||||||||||||
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Nile rats ( Arvicanthis niloticus ) |
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| Scientific name | ||||||||||||
| Arvicanthis | ||||||||||||
| Lesson , 1842 |
The Kusu rats ( Arvicanthis ) are a rodent genus from the group of old world mice (Murinae). In Africa , their home country, they are mostly called "grass rats" or "grass mice" - a term that is also used for other species of rodent.
features
Kusu rats are quite large Old World mice with a head body length between 11 and 20 centimeters and a 9 to 16 centimeter long tail. Their weight is 50 to 180 grams. They have a bristly fur, the color of which is very variable, the spectrum ranges from light gray to black-brown. Sometimes a dark eel line is faintly visible. The bottom is always slightly lighter than the top. The ears are reddish and the hairy tail, which is usually shorter than the torso, is also two-colored as the body.
distribution and habitat
The distribution area of the Kusuratten extends from the Arabian Peninsula and the Nile Valley over large parts of Africa south of the Sahara to Zambia . The African savannas are the main habitat for these animals. They are absent in dense forests, but tolerate semi-deserts . In Ethiopia they can be found in the highlands up to an altitude of 3700 meters.
Way of life
Kusu rats are sociable animals. They live in groups made up of several males and females. In some years there are real population explosions. At the beginning of the 1970s there was such a proliferation in the Serengeti National Park , which led to the fact that a person frightened these animals with every step. The carcasses of the dead kusurats lay in abundance in the lanes, and the living fed on them. In the Sahel zone there was a comparable population explosion in 1976, but it collapsed again in 1977.
Several couples can find each other in a Kusuratten group and raise young ones at the same time. Under favorable conditions, young can be littered all year round, but there is usually a break in the dry season. On average, five young are born. They are suckled for three weeks and are sexually mature after three months. The female cubs stay in their group, while the males usually leave. Although in one case a captive specimen lived to be six and a half years old, life expectancy in the wild is short: an average of ten months is estimated, and twenty months seems to be the maximum.
Kusu rats live in burrows, the entrances of which are hidden under tree roots, bushes or rocks or embedded in termite mounds . They are almost pure herbivores that feed on grasses, leaves and seeds. Insects are only eaten in exceptional cases.
Because of their abundance, kusu rats play an essential role as prey for other animals. In many regions of Africa, kusurats are likely to make up 25% of the barn owl's diet . Other enemies of the Kusu rats are mongooses , jackals , snakes and buzzards .
Kusu rats and people
In their entire area of distribution, Kusu rats are considered to be agricultural pests. In the years of their mass reproduction, they can destroy entire harvests in large regions. In addition, they are considered to be pathogens that could have contributed to the spread of the plague in ancient Egypt .
With the exception of A. blicki , who is listed as “ near threatened ” , the Kusu rats are not endangered according to the IUCN .
Systematics
Within the old world mice, the Kusu rats are the namesake of the Arvicanthis genus group, which are also the Harrington rats ( Desmomys ), the striped grass mice ( Lemniscomys ), the African furrow tooth rats ( Mylomys ), the furrow tooth brook rats ( Pelomys ) and the African welts - Includes grass mice ( Rhabdomys ).
According to genetic studies by Lecompte et al. (2008) the animals of the Arvicanthis group are part of a predominantly African radiation of Old World mice, which also includes the Aethomys group , Dasymys group , Golunda group , Hybomys group and Oenomys group and which are classified as Arvicanthini can be summarized. With the actual rats ( Rattus ), however, there is only a very distant relationship.
There is disagreement about the number of species. Wilson & Reeder (2005) distinguish the following seven types:
- Arvicanthis abyssinicus lives in the highlands of Ethiopia.
- Arvicanthis ansorgeri is widespread in western Africa, from Senegal to Niger.
- Arvicanthis blicki occurs in the eastern part of the highlands of Ethiopia.
- Arvicanthis nairobae lives in southern Kenya and northern Tanzania.
- Arvicanthis neumanni is distributed from Somalia to Tanzania.
- The Nile rat or Nile grass rat ( Arvicanthis niloticus ) has the largest distribution area, stretching from the Nile Valley and Yemen to Zambia.
- Arvicanthis rubinus lives in western Africa, the species has so far only been confirmed unequivocally from Ghana and Benin, but is likely to have a larger distribution area.
literature
- Ronald M. Nowak: Walker's Mammals of the World. 2 volumes. 6th edition. Johns Hopkins University Press, Baltimore MD u. a. 1999, ISBN 0-8018-5789-9 .
- 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 .
- Emilie Lecompte, Ken Aplin , Christiane Denys , François Catzeflis, Marion Chades, Pascale Chevret: Phylogeny and biogeography of African Murinae based on mitochondrial and nuclear gene sequences, with a new tribal classification of the subfamily. In: BMC Evolutionary Biology. Vol. 8, 199, 2008, pp. 1-21, doi: 10.1186 / 1471-2148-8-199 .
Web links
- Arvicanthis on the IUCN Red List of Threatened Species. Retrieved October 6, 2009.