| Blind mole-rat | |
|---|---|
 | |
| Middle East blind mole-rat (Nannospalax ehrenbergi) | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | Spalacidae |
| Subfamily: | Spalacinae Gray, 1821 |
| Genera | |
Theblind mole-rats, also known as thefossorial orsubterranean mole rats, are asubfamily (Spalacinae) ofrodents in the familySpalacidae, found ineastern Europe andwestern andcentral Asia. Thehystricognath mole-rats of the familyBathyergidae are completely unrelated, but some other forms are also in the familySpalacidae.Zokors (subfamilyMyospalacinae), root rats, andbamboo rats (subfamilyRhizomyinae) are spalacids also sometimes referred to as mole rats.
Blind mole-rats are in thefamilySpalacidae, but are unique enough to be given a separatesubfamily,Spalacinae. Alternate opinions ontaxonomy consider the blind mole-rats to be the only members of the familySpalacidae and rank other spalacid subfamilies as full families. Other authors group all members of thesuperfamilyMuroidea into a single family,Muridae. The Spalacinae contains twogenera and eightspecies. Some authorities treat all species as belonging to a single genus,Spalax, but more recent studies indicate a deep divergence between both lineages dating back to theLate Miocene, supporting them as being distinct genera.[1][2]
Spalacinae mole-rats are trulyblind.[3] Their very small eyes are completely covered by a layer of skin. Unlike many otherfossorialrodents, 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 powerfulfront teeth, 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 fromspalacids that used their front limbs to dig, because theirolecranon processes are large relative to the rest of their arms. The olecranon process is a part of theulna bone where muscles attach, anddigging animals tend to have enlarged olecranon processes to provide a large surface for their large and powerfulmuscles to attach.[4]
Because they are completely blind, blind mole-rats have been important laboratory animals in tests on howeyes and eyeproteins function. Although blind mole-rats have only atrophied subcutaneous eyes and are sightless, theircircadian rhythm is kept. A few publications, such as Aviviet al., 2002, have proven that the circadian genes that control the biological clock areexpressed in a similar manner as in sighted, above-ground mammals.[5]
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