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Northern Rock Deermouse

Peromyscus nasutus

French: Péromyscus du Colorado / German: Nordliche Felsen-Hirschmaus / Spanish: Ratén ciervo de roca septentrional

Other common names: Northern Rock Mouse

Taxonomy. Vesperimus nasutus J. A. Allen, 1891, Estes Park, Larimer County, Colorado, USA.

Peromyscus nasutus is in the true: species group. Initially described as a species, it was later placed as a subspecies of P. dif ficilis. Chromosome, allozyme, and DNA studies have confirmed that P. nasutus should be recognized as a species separate from P. difficilis . Three subspecies recognized.

Subspecies and Distribution.

P. n. nasutusJ. A. Allen, 1891 — from SE Utah and NC Colorado S through E Arizona, New Mexico, and W Texas, USA, to C Coahuila, Mexico.

P.n.griseusBenson,1932—restrictedtolavafieldssurroundingthetypelocalityinCNewMexico,USA.

P.n. penicillatus Mearns, 1896 — restricted to a narrow band along the USA-Mexico border from El Paso, Texas, to Sierra del Carmen, Coahuila.

Descriptive notes. Head—body 99-107 mm, tail 121-134 mm, ear 21-26 mm, hindfoot 22-26 mm; weight 25-35 g. The Northern Rock Deermouse is medium-sized, with grayish brown dorsum and gray underfur. Venteris whitish, mixed with gray underfur; occasionally there is an orange pectoral spot. Sides are ocherous yellow. Earsare large. Hindfeet are whitish to metatarsal region. Tail is bicolored and generally longer than head-body length. The Northern Rock Deermouse closely resembles the Southern Rock Deermouse ( P. difficilis), but it is slightly smaller.

Habitat. Rocky foothill and montane habitats ranging from desert scrublands and grasslands to pine-oak forests at elevations of 2000-3117 m.

Food and Feeding. The Northern Rock Deermouse mainly eats acorns, stems, and roots.

Breeding. Breeding season of the Northern Rock Deermouse occurs in July-December. Lactating females have been caught in December, so presumably most offspring are born in autumn and early winter. Litters have 3-4 young.

Activity patterns. Northern Rock Deermice are presumably nocturnal and might be partially arboreal. They construct burrows in cracks of rocks, tree stumps, trunks, and holes of trees.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Baker (1956), Chavez, J.C. (2014d), Durish et al. (2004), Hall (1981), Hoffmeister & de la Torre (1961), Horner (1954), Musser & Carleton (2005), Osgood (1909), Zimmerman, Hart & Kilpatrick (1975), Zimmerman, Kilpatrick & Hart (1978).