The blind mole-rats, also known as the fossorial or subterranean mole rats, are a

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

(Spalacinae) of

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

s in the family

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 southeastern Europe. It includes the blind mole-rats, bamboo rats, mole ...

, found in

eastern Europe Eastern Europe is a subregion of the Europe, European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural, and socio-economic connotations. The vast majority of the region is covered by Russ ...

and

western Western may refer to: Places *Western, Nebraska, a village in the US *Western, New York, a town in the US *Western Creek, Tasmania, a locality in Australia *Western Junction, Tasmania, a locality in Australia *Western world, countries that id ...

central Asia Central Asia, also known as Middle Asia, is a subregion, region of Asia that stretches from the Caspian Sea in the west to western China and Mongolia in the east, and from Afghanistan and Iran in the south to Russia in the north. It includes t ...

. The

hystricognath The Hystricognathi are an infraorder of rodents, distinguished from other rodents by the bone structure of their skulls. The masseter medialis (a jaw muscle) passes partially through a hole below each eye socket (called the infraorbital foramen) ...

mole-rats of the family Bathyergidae are completely unrelated, but some other forms are also in the family

Zokor Zokors are Asiatic burrowing rodents resembling mole-rats. They include two genera: ''Myospalax'' and ''Eospalax''. Zokors are native to much of China, Kazakhstan, and Siberia, Siberian Russia. Traditionally, zokors were thought to be closely ...

s (subfamily

Myospalacinae Zokors are Asiatic burrowing rodents resembling mole-rats. They include two genera: ''Myospalax'' and ''Eospalax''. Zokors are native to much of China, Kazakhstan, and Siberian Russia. Traditionally, zokors were thought to be closely related ...

), root rats, and bamboo rats (subfamily

Rhizomyinae The rodent subfamily Rhizomyinae 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. The ...

) are spalacids also sometimes referred to as mole rats. Blind mole-rats are in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

, but are unique enough to be given a separate

, Spalacinae. Alternate opinions on

taxonomy Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

consider the blind mole-rats to be the only members of the family

and rank other spalacid subfamilies as full families. Other authors group all members of the

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

Muroidea The Muroidea are a large superfamily of rodents, including mice, rats, voles, hamsters, lemmings, gerbils, and many other relatives. Although the Muroidea originated in Eurasia, they occupy a vast variety of habitats on every continent except A ...

into a single family,

Muridae The Muridae, or murids, are the largest family of rodents and of mammals, containing approximately 1,383 species, including many species of mice, rats, and gerbils found naturally throughout Eurasia, Africa, and Australia. The name Muridae come ...

. The Spalacinae contains two

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

and eight

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

. Some authorities treat all species as belonging to a single genus, ''

Spalax ''Spalax'' is a genus of rodent in the family Spalacidae, subfamily ''Spalacinae'' (blind mole-rats). It is one of two extant genera in the subfamily Spalacinae, alongside ''Nannospalax''.' Species in this genus are found in eastern Europe a ...

'', but more recent studies indicate a deep divergence between both lineages dating back to the

Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million ye ...

, supporting them as being distinct genera.'''' Spalacinae mole-rats are truly blind. Their very small eyes are completely covered by a layer of skin. Unlike many other

fossorial A fossorial () animal is one adapted to digging which lives primarily, but not solely, underground. Some examples are badgers, naked mole-rats, clams, meerkats, and mole salamanders, as well as many beetles, wasps, and bees. Prehistoric eviden ...

s, blind 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 Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

, which are separated from the rest of the mouth by a flap of skin. When a blind mole-rat closes its mouth, its incisors are still on the outside. Blind mole-rats may have evolved from spalacids that used their front limbs to dig, because their

olecranon process The olecranon (, ), is a large, thick, curved bony eminence of the ulna, a long bone in the forearm that projects behind the elbow. It forms the most pointed portion of the elbow and is opposite to the cubital fossa or elbow pit. The olecranon ...

es are large relative to the rest of their arms. The olecranon process is a part of the

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

bone where muscles attach, and digging animals tend to have enlarged olecranon processes to provide a large surface for their large and powerful

muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...

s to attach. Because they are completely blind, blind mole-rats have been important laboratory animals in tests on how

eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...

s and eye

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

s function. Although blind mole-rats have only atrophied subcutaneous eyes and are sightless, their

circadian rhythm A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., Endogeny (biology), endogeno ...

is kept. A few publications, such as Avivi ''et al.'', 2002, have proven that the circadian genes that control the biological clock are expressed in a similar manner as in sighted, above-ground mammals.

Classification

* Subfamily Spalacinae - blind mole-rats ** Genus ''

'' ***

Mehely's blind mole-rat Mehely's blind mole-rat (''Spalax antiquus'') is an endangered species of rodent in the family Spalacidae. It is endemic to Romania. Taxonomy Previously described in 1909 by Lajos Méhelÿ as a subspecies of the Balkan mole-rat (''S. graecus'' ...

'', S. antiquus'' ***

Sandy blind mole-rat The sandy blind mole-rat (''Spalax arenarius'') is an endangered species of rodent in the family Spalacidae. It is endemic to Ukraine. It was first identified by Evdokia Reshetnik in 1939. Distribution and habitat It is restricted to a very s ...

, ''S. arenarius'' ***

Giant blind mole-rat The giant blind mole-rat (''Spalax giganteus'') is a species of rodent in the family Spalacidae endemic to the North Caucasus region of Russia. It feeds on roots and tubers and lives underground in a burrow that it digs with its teeth. Distribu ...

, ''S. giganteus'' ***

Bukovina blind mole-rat The Bukovina blind mole-rat or (erroneously) the Balkan blind mole-rat (''Spalax graecus'') is a species of rodent in the family Spalacidae found in Romania, Moldova, and Ukraine. Taxonomy The specific epithet ''graecus'', as well as the re ...

, ''S. graecus'' ***

Oltenia blind mole-rat The Oltenia blind mole-rat (''Spalax istricus'') is a critically endangered, possibly extinct species of rodent in the family Spalacidae. It is endemic to Romania. Taxonomy Previously described in 1909 by Lajos Méhelÿ as a subspecies of the ...

, ''S. istricus'' (possibly

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

) ***

Greater blind mole-rat The greater blind mole-rat (''Spalax microphthalmus'') is a species of rodent in the family Spalacidae. It is found in Russia and Ukraine. Description The greater blind mole-rat is tailless. The eyes are covered by a membrane of skin and have at ...

, ''S. microphthalmus'' ***

Kazakhstan blind mole-rat The Kazakhstan blind mole-rat or Ural blind mole-rat (''Spalax uralensis'') is a species of rodent in the family Spalacidae. It is endemic to Kazakhstan, along the Ural River basin and the flood plains of the Uil, Temir, and Emba rivers. Wher ...

, ''S. uralensis'' ***

Podolsk blind mole-rat The Podolsk blind mole-rat or Podolian mole-rat (''Spalax zemni'') is a species of rodent in the family Spalacidae. It is endemic to western and central Ukraine. Distribution and habitat It has a wide but severely fragmented range throughout U ...

, ''S. zemni'' ** Genus ''

Nannospalax ''Nannospalax'' is a genus of rodent in the family Spalacidae, found in eastern Europe and western Asia. It is one of two genera in the blind mole-rats (subfamily Spalacinae), alongside ''Spalax''. Members of this genus are also known as small-bod ...

'' - small-bodied mole-rats *** Subgenus ''Nannospalax'' ****

Middle East blind mole-rat The Middle East blind mole-rat or Palestine mole-rat (''Nannospalax ehrenbergi'') is a species of rodent in the family Spalacidae. Taxonomy It was formerly classified in the genus ''Spalax'', but more recent phylogenetic evidence supports it a ...

or Palestine mole-rat, ''N. ehrenbergi'' *** Subgenus ''Mesospalax'' ****

Lesser blind mole-rat The lesser blind mole-rat (''Spalax leucodon'') is a species of rodent in the family Spalacidae. It is found in Albania, Bosnia and Herzegovina, Bulgaria, Greece, Hungary, Macedonia, Romania, Serbia, Montenegro, Turkey and Ukraine. Prior to 20 ...

, ''N. leucodon'' ****

Anatolian blind mole-rat The Anatolian blind mole-rat or Nehring's blind mole-rat (''Nannospalax xanthodon'') is a species of rodent in the family Spalacidae. It is found in Armenia, Georgia, and Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ...

or Nehring's blind mole-rat, ''N. xanthodon''

References

{{Taxonbar, from=Q14153702 Spalacidae