Heterocephalus glaber, Ruppell, 1842

Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Heterocephalidae, Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona: Lynx Edicions, pp. 351-351 : 351

Naked Mole-rat

Heterocephalus glaber

French: Hétérocéphale / German: Nacktmull / Spanish: Rata topo lampina

Other common names: Desert Mole Rat, Sand Puppy

Taxonomy. Heterocephalus glaber Ruppell, 1842 ,

“Abyssinien und Schoa” (= Ethiopia and [central province of] Shewa).

The generic synonym, Fornarina , named by O. Thomas in 1903, was never widely used, and no subspecies are recognized. Heterocephalus glaber is known to vary geographically in genetics, morphology, and chromosomes; Ethiopian and Kenyan populations differ in cytochrome-b sequences, reaching a threshold often shown by distinct species. No integrative revision of the species has been possible because of the need for additional sampling and political strife in much ofits distribution. Monotypic.

Distribution. Djibouti, E & S Ethiopia, Somalia, and N & E Kenya.

Descriptive notes. Head-body 70-110 mm, tail 30-50 mm; weight 15-70 g (mostly 30-35 g). The Naked Mole-rat has pinkish naked skin, studded only by sensory vibrissae. Its strongly protruding incisors are unmistakable. Eyes are tiny, and ear pinnae are minute. Tail is longer than hindfoot. Limbs are short and slender, and third digit of manus is markedly longer than digit four. Cranially,jugal bone is reduced and supported anteriorly by zygomatic portion of maxillary, palate is not excessively constricted between cheekteeth and does not extend behind molars, andjaws bear only 2-3 upper and lower cheekteeth.

Habitat. Subterranean arid bushland and thicket and semi-desert biomes with low and irregular rainfall (averaging 200-400 mm annually). Naked Mole-rats occupy habitats at elevations of 300-1500 m. They are the only subterranean rodent within their distribution. Food and Feeding. The Naked Mole-rat feeds on bulbs, roots, and tubers in closed, underground burrow systems. These foods supply all of its needed water.

Breeding. The Naked Mole-rat is eusocial and lives in colonies averaging 40-80 individuals. Reproduction is typically limited to a single reproductive female (“queen”) and 1-2 breeding males; remaining colony members are reproductively suppressed by agonistic encounters with breeders. Gestation is 66-74 days, with litters of 1-28 young. Dominant females have litters every 76-84 days and,in the wild, regularly produce 4-5 litters/year and 50 or more young.

Activity patterns. Naked Mole-rats are active around the clock, and activity periods are punctuated by resting bouts, often en masse. Most active digging follows rains that reduce soil hardness and thus energetic costs involved in expanding the burrow system. Movements, Home range and Social organization. Naked Mole-rats are highly social. Within a colony, there is a size-based dominance hierarchy, with larger individuals gaining preferential access to contested resources through shoving matches. Colonies range throughout a burrow system, which may be 0-5-3 km in length. They are strictly territorial and gradually shift from maintenance activities to digging, foraging, and burrow defense over the course of theirlives.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Naked Mole-rat is widely distributed, relative common, and lacks immediate threats. Nevertheless, its inbred breeding system and infrequent dispersals raise concerns about their ability to respond to changing land-use patterns or climate.

Bibliography. Bennet & Faulkes (2000), Brett (1991b), Bugge (1974, 1985), Cox & Faulkes (2014), De Graaff (1975), Ellerman (1940), Fang Xiaodong etal. (2014), Faulkes & Bennett (2007), Faulkes, Abbott & Mellor (1990), Faulkes, Abbott, O'Brien et al. (1997), Honeycutt et al. (1991), Ingram et al. (2014), Jarvis & Sherman (2002), Judd & Sherman (1996), Kim Eun-Bae etal. (2011), Kotzé, Van der Merwe, Bennett & O’Riain (2010), Kotzé, Van der Merwe, Ndou et al. (2009), Landry (1957a, 1999), Lavocat (1974), Lavocat & Parent (1985), Luckett (1985), O'Riain & Jarvis (1997), Prochel et al. (2014), Smith et al. (2012), Thomas (1903c), Tian Xiao et al. (2013), Wood (1985), Woods (1975, 1984), Yosida & Okanoya (2009).

Figures

Naked Mole-rat

Distribution. Djibouti, E & S Ethiopia, Somalia, and N & E Kenya.