Blind mole rat
Encyclopedia
The genus Spalax contains the blind, fossorial, or subterranean mole rats, which are one of several types of rodent
s that are called mole rats. The hystricognath
mole rats of the family Bathyergidae are completely unrelated, but some other forms are also in the family Spalacidae
. Zokor
s (subfamily Myospalacinae) and root rats and bamboo rat
s (subfamily Rhizomyinae
) are spalacids sometimes referred to as mole rats. Blind mole rats are in the family
Spalacidae
, but are unique enough to be given a separate subfamily, Spalacinae. Alternate opinions on taxonomy
consider the blind mole rats to be the only members of the family Spalacidae
and rank other spalacid subfamilies as full families. Other authors group all members of the superfamily
Muroidea
into a single family, Muridae
. The Spalacinae contains two genera
and eight species
. Some authorities treat all species as belonging to a single genus, Spalax.
Spalax mole rats are truly blind
. Their very small eyes are completely covered by a layer of skin. Unlike many other fossorial
rodent
s, Spalax mole rats do not have enlarged front claws and do not appear to use their forearms as a primary digging tool. Digging is almost exclusively conducted using their powerful front teeth
, which are separated from the rest of the mouth by a flap of skin. When a Spalax mole rat closes its mouth, its incisors are still on the outside. It has been suggested that blind mole rats may have evolved from spalacids
that used their front limbs to dig, because their olecranon process is relatively large relative to the rest of the arm. The olecranon process is a part of the ulna
bone where muscles attach, and digging animals
tend to have enlarged olecranon processes to provide a lot of surface for their large and powerful muscle
s to attach.
Because they are completely blind, blind mole rats have been important laboratory animals in tests on how eye
s and eye protein
s function.
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....
s that are called mole rats. The hystricognath
Hystricognathi
Hystricognathi is an infraorder of rodents. Hystricognaths are distinguished from other rodents by the bone structure of their skulls. The masseter medialis passes partially through the infraorbital foramen and connects to the bone on the opposite side...
mole rats of the family Bathyergidae are completely unrelated, but some other forms are also in the family Spalacidae
Spalacidae
The Spalacidae, or spalacids are a family of rodents in the large and complex superfamily Muroidea. They are native to eastern Asia, the Horn of Africa, the Middle East, and south-eastern Europe. It includes the blind mole rats, bamboo rats, root rats, and zokors...
. Zokor
Zokor
Zokors are Asiatic burrowing rodents resembling mole rats. They include two genera, Myospalax and Eospalax. Zokors are native to much of China, Kazhakstan, and Siberian Russia....
s (subfamily Myospalacinae) and root rats and bamboo rat
Bamboo rat
The bamboo rats are four species of rodents of the subfamily Rhizomyinae. They are the sole living representatives of the tribe Rhizomyini. All are found in the eastern half of Asia.The species are:...
s (subfamily Rhizomyinae
Rhizomyinae
The subfamily Rhizomyinae of rodents includes the Asian bamboo rats and certain of the African mole rats. The subfamily is grouped with the Spalacinae and the Myospalacinae into a family of fossorial muroid rodents basal to the other Muroidea....
) are spalacids sometimes referred to as mole rats. Blind mole rats are in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Spalacidae
Spalacidae
The Spalacidae, or spalacids are a family of rodents in the large and complex superfamily Muroidea. They are native to eastern Asia, the Horn of Africa, the Middle East, and south-eastern Europe. It includes the blind mole rats, bamboo rats, root rats, and zokors...
, but are unique enough to be given a separate subfamily, Spalacinae. Alternate opinions on taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
consider the blind mole rats to be the only members of the family Spalacidae
Spalacidae
The Spalacidae, or spalacids are a family of rodents in the large and complex superfamily Muroidea. They are native to eastern Asia, the Horn of Africa, the Middle East, and south-eastern Europe. It includes the blind mole rats, bamboo rats, root rats, and zokors...
and rank other spalacid subfamilies as full families. Other authors group all members of the superfamily
Taxonomic rank
In biological classification, rank is the level in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class. Each rank subsumes under it a number of less general categories...
Muroidea
Muroidea
Muroidea is a large superfamily of rodents. It includes hamsters, gerbils, true mice and rats, and many other relatives. They occupy a vast variety of habitats on every continent except Antarctica. Some authorities have placed all members of this group into a single family, Muridae, due to...
into a single family, Muridae
Muridae
Muridae is the largest family of mammals. It contains over 600 species found naturally throughout Eurasia, Africa, and Australia. They have been introduced worldwide. The group includes true mice and rats, gerbils, and relatives....
. The Spalacinae contains two genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
and eight species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
. Some authorities treat all species as belonging to a single genus, Spalax.
Spalax mole rats are truly blind
Blindness
Blindness is the condition of lacking visual perception due to physiological or neurological factors.Various scales have been developed to describe the extent of vision loss and define blindness...
. Their very small eyes are completely covered by a layer of skin. Unlike many other fossorial
Fossorial
A fossorial organism is one that is adapted to digging and life underground such as the badger, the naked mole rat, and the mole salamanders Ambystomatidae...
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....
s, Spalax mole rats do not have enlarged front claws and do not appear to use their forearms as a primary digging tool. Digging is almost exclusively conducted using their powerful front teeth
Incisor
Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...
, which are separated from the rest of the mouth by a flap of skin. When a Spalax mole rat closes its mouth, its incisors are still on the outside. It has been suggested that blind mole rats may have evolved from spalacids
Spalacidae
The Spalacidae, or spalacids are a family of rodents in the large and complex superfamily Muroidea. They are native to eastern Asia, the Horn of Africa, the Middle East, and south-eastern Europe. It includes the blind mole rats, bamboo rats, root rats, and zokors...
that used their front limbs to dig, because their olecranon process is relatively large relative to the rest of the arm. The olecranon process is a part of the ulna
Ulna
The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In anatomical position The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form...
bone where muscles attach, and digging animals
Fossorial
A fossorial organism is one that is adapted to digging and life underground such as the badger, the naked mole rat, and the mole salamanders Ambystomatidae...
tend to have enlarged olecranon processes to provide a lot of surface for their large and powerful muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
s to attach.
Because they are completely blind, blind mole rats have been important laboratory animals in tests on how eye
Eye
Eyes are organs that detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptors in conscious vision connect light to movement...
s and eye protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s function.
Classification
Subfamily Spalacinae- Genus Spalax – Blind mole rats
- Sandy Mole RatSandy Mole RatThe Sandy Mole Rat is a species of rodent in the Spalacidae family. It is endemic to Ukraine.-References:* Baillie, J. 1996. . Downloaded on 30 July 2007....
, Spalax arenarius - Mt. Carmel Blind Mole Rat, Spalax carmeli
- Middle East Blind Mole RatMiddle East Blind Mole RatThe Middle East Blind Mole Rat or Israel Mole Rat is a species of rodent in the Spalacidae family....
, Spalax ehrenbergi - Upper Galilee Mountains Blind Mole Rat, Spalax galili
- Giant Mole RatGiant Mole RatThe Giant Mole Rat or Russian Mole Rat is a species of rodent in the Spalacidae family. It is found in Kazakhstan and Russia.-References:...
, Spalax giganteus - Golan Heights Blind Mole RatGolan Heights Blind Mole RatThe Golan Heights Blind Mole Rat is a species of rodent in the Spalacidae family. The species have been found on the Golan Heights, ....
, Spalax golani - Balkan Mole RatBalkan Mole RatThe Balkan Mole Rat or Bukovin Mole Rat is a species of rodent in the Spalacidae family. It is found in Romania, the Republic of Moldova and Ukraine.-References:* Amori, G. 1996. . Downloaded on 30 July 2007....
, Spalax graecus - Judean Mountains Blind Mole Rat, Spalax judaei
- Lesser Mole RatLesser Mole RatThe Lesser Mole Rat is a species of rodent in the Spalacidae family. It is found in Bosnia and Herzegovina, Bulgaria, Greece, Hungary, Macedonia, Romania, Serbia, Montenegro, Turkey, and Ukraine...
, Spalax leucodon - Greater Mole RatGreater Mole RatThe Greater Mole Rat is a species of rodent in the Spalacidae family. It is found in Russia and Ukraine.-Description:...
, Spalax microphthalmus - Munzur Mole Rat, Spalax munzuri
- Nehring's Blind Mole RatNehring's Blind Mole RatNehring's Blind Mole Rat is a species of rodent in the family Muridae.It is found in Armenia, Georgia, and Turkey.-References:* Baillie, J. 1996. . Downloaded on 9 July 2007....
, Spalax nehringi - Kazakhstan Blind Mole Rat, Spalax uralensis
- Podolsk Mole RatPodolsk Mole RatThe Podolsk Mole Rat is a species of rodent in the Spalacidae family. It is an endemic of western and central Ukraine.-References:* Amori, G. 1996. . Downloaded on 30 July 2007....
, Spalax zemni
- Sandy Mole Rat