Rock rat
| Rock rat | ||||||||||||
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Rock rat ( Petromus typicus ) |
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Petromuridae | ||||||||||||
| Wood , 1955 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Petromus | ||||||||||||
| A. Smith , 1831 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Petromus typicus | ||||||||||||
| A. Smith , 1831 |
The rock rat or Noki ( Petromus typicus ) is a species of rodent . It is the only member of the Petromuridae family and has no close living relatives. Despite the name, it is not closely related to the rats (genus Rattus ).
features
Rock rats reach a head body length of 14 to 22.5 centimeters, a tail length of 11.5 to 17.5 centimeters and a weight of 100 to about 300 grams. The rear foot length is 27 to 40 millimeters, the ear length 10 to 17 millimeters.
Rock rats are medium-sized to large rodents and are somewhat similar to squirrels . The fur is long and the tail is long hairy, but not bushy. Depending on the regional distribution, the back fur is blackish-brown, dark gray or pale sand-colored yellow. The color of the peritoneum corresponds to the fur on the back, but is a little paler. Your head is flattened dorsoventrally. Its coloration also corresponds to the fur on the back, only the nasal region, the lips and the area around the eyes are somewhat paler. The eyes are large, the small and oval ears are slate-gray to black in color and have sparse hairs made up of very short hair. The rock rats have short limbs and large feet. They are clearly hairy on top and bare underneath. On the front paws there are four toes and a rudimentary first toe, below they have three pads at the base of the toes and two on the rear sole. They have five toes on their hind paws, below they also have three pads at the base of the toes and only one on the sole. All toes have very well developed and sharp, short claws. The tail reaches about 85% of the head-trunk length and is therefore relatively long, it is clearly covered with long hair. At the base the color of the tail corresponds to the color of the back, the rear three quarters are darker to black. At rest, the tail is placed on the ground and not carried over the body as with croissants. The males' scrotum is normal. The females have two to three pairs of teats , two in the chest area behind the shoulders and one, which can also be missing, in the lumbar area.
distribution
Rock rats inhabit dry, rocky areas in southwestern Africa ; they live in southwestern Angola and Namibia as well as northwestern South Africa .
Way of life
The rock rats' habitat are dry areas in the hill country or mountains, which are often crisscrossed with crevices. These serve them as shelter, mainly in the morning and late afternoon they come out to look for food or bask in the sun. In doing so, they make sure to stay hidden under overhanging rocks as often as possible so as not to be seen by birds of prey , their main predators. Their physique is more adapted to a running than a jumping locomotion, but sometimes they hop between the rocks, where they stretch their bodies like the flying squirrels . Rock rats live alone or in pairs. One study found 15 specimens in a six hectare area. They often live in the same habitat as rock hyrax, and their smaller size means there is no competition for protective crevices in the rock.
The animals feed on herbivores , so they are herbivores. Their diet mainly includes grasses, seeds and berries.
The mating takes place in early summer (November to December), after a three-month gestation period, one to three young animals are born. These are hairy and relatively well developed. Females have three pairs of teats that lie on the sides of the body at shoulder blade level, so that suckling in narrow crevices is made possible. The boys start eating solid food at around two weeks and are weaned at three weeks. Nothing is known about life expectancy.
Systematics
The rock rat is classified as an independent and only species within the monotypical genus Petromus and the Petromuridae family, which also only consists of this species. They belong to the porcupine relatives (Hystricomorpha) within the rodents , their closest relatives are the cane rats . The first scientific description comes from the British zoologist Andrew Smith from 1831, who described the animals from the mountainous region on the lower reaches of the Orange from "Little Namaqualand". The first description was under the name Petromus typicus , which is still valid today , but in 1834 Smith named the genus as Petromus , whereupon some later synonyms and derivatives were described under this name.
In addition to the nominate form, numerous subspecies have been described within the species , which perhaps also indicate a species complex. However, according to the current status, these are not recognized. In order to confirm this, however, further phylogenetic studies are required, so far only several geographical variant groups have been differentiated accordingly.
Fossil ancestors of these animals have been known since the Oligocene , all finds are limited to Africa.
Status, threat and protection
The rock rat is classified by the International Union for Conservation of Nature and Natural Resources (IUCN) as not endangered (least concern). This is justified by the comparatively large distribution area and the assumed large populations as well as the occurrence in several protected areas. There are no known threats to the existence of the species, but the animals are often hunted by domestic cats in the outskirts of cities and populated areas .
supporting documents
- ↑ a b c d C.G. Coetzee: Petromus typicus - Noki (Dassie Rat) In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume III. Rodents, Hares and Rabbits. Bloomsbury, London 2013, p. 681; ISBN 978-1-4081-2253-2 .
- ↑ a b c d Petromus typicus in the IUCN Red List of Threatened Species 2016.2. Posted by: M. Griffin, N. Coetzee, 2008. Retrieved October 3, 2016.
- ↑ a b Cryptomys kafuensis . 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 .
- ^ A b R. López-Antoñanzas: Petromuridae (Noki). In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (editors): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6), Lynx Edicions, Barcelona 2016; P. 336 ff. ISBN 978-84-941892-3-4 .
literature
- R. López-Antoñanzas: Petromuridae (Noki). In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (editors): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6), Lynx Edicions, Barcelona 2016; P. 336 ff. ISBN 978-84-941892-3-4 .
- CG Coetzee: Petromus typicus - Noki (Dassie Rat) In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume III. Rodents, Hares and Rabbits. Bloomsbury, London 2013, p. 681; ISBN 978-1-4081-2253-2 .
Web links
- Petromus typicus inthe IUCN 2016 Red List of Threatened Species . Posted by: M. Griffin, N. Coetzee, 2008. Retrieved October 3, 2016.