Dassie Rat
Encyclopedia
The dassie rat, Petromus typicus, is an Africa
n rodent
found among rocky outcroppings. It is the only living member of its genus, Petromus, and family, Petromuridae. The name "dassie" means "hyrax
" in Afrikaans
, and the two animals are found in similar habitats. Petromus means "rock mouse" and dassie rats are one of many rodents that are sometimes called rock rats. The family and genus names are sometimes misspelled as Petromyidae and Petromys.
-like in appearance. Their tail
s are hairy, but not bushy whereas the soles
of their feet are distinctly bare and have pads. Their heads are noticeably flattened. The overall coloration can be a range of browns, greys, or almost black. The nose is yellowish and tends to stand out. They have no underfur. The teats are located on the sides of the torso, which allows the young to feed from the side when crammed in a narrow rock crevice.
, parts of Angola
and northwest South Africa
. They are famous for being able to squeeze into extremely narrow crevices. This is accomplished due to their flattened skulls and flexible ribs.
Dassie rats feed primarily on grass
y parts, but will sometimes eat fruit
s, seeds, and leaves
. They have high crowned and rooted cheek teeth. Females give birth to a pair of offspring just once a year; an unusually slow reproductive rate among rodents.
of Africa. Both morphological
and molecular studies suggest the closest living relatives to the dassie rats are the African cane rat
s in the family Thryonomyidae. These two families along with related fossil families such as †Phiomyidae
represented an important early radiation of rodents in Africa.
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
n rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
found among rocky outcroppings. It is the only living member of its genus, Petromus, and family, Petromuridae. The name "dassie" means "hyrax
Hyrax
A hyrax is any of four species of fairly small, thickset, herbivorous mammals in the order Hyracoidea. The rock hyrax Procavia capensis, the yellow-spotted rock hyrax Heterohyrax brucei, the western tree hyrax Dendrohyrax dorsalis, and the southern tree hyrax, Dendrohyrax arboreus live in Africa...
" in Afrikaans
Afrikaans
Afrikaans is a West Germanic language, spoken natively in South Africa and Namibia. It is a daughter language of Dutch, originating in its 17th century dialects, collectively referred to as Cape Dutch .Afrikaans is a daughter language of Dutch; see , , , , , .Afrikaans was historically called Cape...
, and the two animals are found in similar habitats. Petromus means "rock mouse" and dassie rats are one of many rodents that are sometimes called rock rats. The family and genus names are sometimes misspelled as Petromyidae and Petromys.
Characteristics
Dassie rats are squirrelSquirrel
Squirrels belong to a large family of small or medium-sized rodents called the Sciuridae. The family includes tree squirrels, ground squirrels, chipmunks, marmots , flying squirrels, and prairie dogs. Squirrels are indigenous to the Americas, Eurasia, and Africa and have been introduced to Australia...
-like in appearance. Their tail
Tail
The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
s are hairy, but not bushy whereas the soles
Sole (foot)
The sole is the bottom of the foot.In humans the sole of the foot is anatomically referred to as the plantar aspect. The equivalent surface in ungulates is the hoof.- Human sole :...
of their feet are distinctly bare and have pads. Their heads are noticeably flattened. The overall coloration can be a range of browns, greys, or almost black. The nose is yellowish and tends to stand out. They have no underfur. The teats are located on the sides of the torso, which allows the young to feed from the side when crammed in a narrow rock crevice.
Natural history
Dassie rats are restricted to rocky outcrops in NamibiaNamibia
Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...
, parts of Angola
Angola
Angola, officially the Republic of Angola , is a country in south-central Africa bordered by Namibia on the south, the Democratic Republic of the Congo on the north, and Zambia on the east; its west coast is on the Atlantic Ocean with Luanda as its capital city...
and northwest South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. They are famous for being able to squeeze into extremely narrow crevices. This is accomplished due to their flattened skulls and flexible ribs.
Dassie rats feed primarily on grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
y parts, but will sometimes eat fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
s, seeds, and leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
. They have high crowned and rooted cheek teeth. Females give birth to a pair of offspring just once a year; an unusually slow reproductive rate among rodents.
Relatives
Dassie rats are the only remaining members of a once diverse family that first appeared in the OligoceneOligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
of Africa. Both morphological
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
and molecular studies suggest the closest living relatives to the dassie rats are the African cane rat
Cane rat
The genus Thryonomys, also known as cane rats, grass cutters, or cutting grass, is a genus of rodent found throughout Africa south of the Sahara, the only members of the family Thyronomyidae. They are eaten in some African countries and are a pest species on many crops.-Characteristics:Cane rats...
s in the family Thryonomyidae. These two families along with related fossil families such as †Phiomyidae
Phiomyidae
The Phiomyidae are a family of prehistoric rodents from Africa and Eurasia. A 2011 study placed Gaudeamus in a new family, gaudeamuridae.Genera include:* Acritophiomys* Andrewsimys* Elwynomys* Gaudeamus* Phiomys...
represented an important early radiation of rodents in Africa.
Further reading
- Kingdon, J. 1997. The Kingdon Field Guide to African Mammals. Academic Press Limited, London.
- McKenna, Malcolm C., and Bell, Susan K. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp. ISBN 0-231-11013-8
- Nowak, R. M. 1999. Walker's MammalMammalMammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s of the World, Vol. 2. Johns Hopkins University Press, London.