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 Genus ( plural genera ) is a taxonomic rank used in the biological classifica ...

(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 n ...

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, m ...

, found in

eastern Europe Eastern Europe is a subregion of the 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 Russia, whi ...

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 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 the fo ...

. 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 Siberian Russia. Traditionally, zokors were thought to be closely relate ...

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 relate ...

), root rats, and

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 South Asia, Southeast Asia and East Asia. The species are: *The Chinese bamboo rat, ''R ...

s (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. T ...

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

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

, 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 excep ...

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 comes ...

. 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 appropriat ...

. 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 ...

'', 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 made up of two stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million years ago) to 5.333 Ma. The ...

, 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 evid ...

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 mus ...

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

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., endogenous) and responds to ...

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. grae ...

'', S. antiquus'' *** Sandy blind mole-rat, ''S. arenarius'' *** Giant blind mole-rat, ''S. giganteus'' *** Bukovina blind mole-rat, ''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 ...

, ''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 ...

, ''S. microphthalmus'' *** Kazakhstan blind mole-rat, ''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 throughou ...

, ''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 or Palestine mole-rat, ''N. ehrenbergi'' *** Subgenus ''Mesospalax'' **** Lesser blind mole-rat, ''N. leucodon'' **** Anatolian blind mole-rat or Nehring's blind mole-rat, ''N. xanthodon''

References

{{Taxonbar, from=Q14153702 Spalacidae