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Cactus Deermouse

Peromyscus eremicus

French: Péromyscus des cactus / German: Kaktus-Hirschmaus / Spanish: Raton ciervo de cactus

Other common names: Cactus Mouse

Taxonomy. Hesperomys eremicus Baird, 1858, Old Fort Yuma; Colorado River opposite Yuma, Arizona; Imperial County; California; USA.

Recently, P. eremicus was separated into two species, assigning P. fraterculus to those on the west of the Colorado River and P. er emicus to those on the east side of the river. Allocation of subspecies is somewhat unclear. Peromyscus eremicus is in the eremicus species group. Recent evidence suggests that P. interparietalis should be recognized as a subspecies of P. eremicus . Fourteen subspecies recognized.

Subspecies and Distribution.

P.e.eremicusBaird,1858—fromSNevadaandSWUtah,USA,S&SEtoNW&NCMexico.

P.e.alcorniS.Anderson,1972—knownonlyfromthetypelocalityandsurroundingareasinNCChihuahua,Mexico.

P.e.anthony:Merriam,1887—SEArizonaandSWNewMexico,USA,andNESonoraandNEChihuahua,Mexico.

P.e.aviusOsgood,1909—knownonlyfromtypelocalityonCerralvoI,BajaCaliforniaSur,Mexico.

P.e.cedrosensisJ.A.Allen,1898—knownonlyfromthetypelocalityonCedrosI,BajaCalifornia,Mexico.

P.e.cinereusHall,1931—knownonlyfromthetypelocalityonSWSanJoséI,BajaCaliforniaSur,Mexico.

P.e.collatusBurt,1932—knownonlyfromthetypelocalityonTurnerI,Sonora,Mexico.

P.e.insulicolaOsgood,1909—knownonlyfromthetypelocalityonEspirituSantoI,BajaCaliforniaSur,Mexico.

P.e.papagensisGoldman,1917—knownonlyfromthetypelocalityandsurroundingareasinSWArizona,USA,andNWSonora,Mexico.

P.e.phaeurusOsgood,1904—ECoahuila,NEZacatecas,WNuevoLeon,andNSanLuisPotosi,Mexico.

P.e.polypoliusOsgood,1909—knownonlyfromthetypelocalityonMargaritaI,BajaCaliforniaSur,Mexico.

P.e.pullusBlossom,1933—knownonlyfromthetypelocalityinCSArizona,USA.

P.e.sinaloensisS.Anderson,1972—E&SSonora,SWChihuahua,andSinaloa,Mexico.

P. e. tiburonensis Mearns, 1897 — known only from the type locality on Tiburén I, Sonora, Mexico.

Descriptive notes. Head—body 77-100 mm, tail 92-118 mm, ear 13-18 mm, hindfoot 18-22 mm; weight 13-18 g. Females typically are larger and heavier than males. The Cactus Deermouse is small, with long and silky dorsal pelage of ocherous buff to cinnamon-buff, washed dusky; sides and head are more of a gray color. A distinct ocherous buff lateral is present. Ventral pelage is white, suffused with buff or tawny. Tail is bicolored (darker above), is longer than head-body length, and has small tuft at end. Ears are small relative to body size. The Cactus Deermouse can be distinguished from other species of Peromyscus in that soles of hindfeet are naked and baculum is relatively short, wide, and dorsally curved, with square and very small base.

Habitat. Sandy and rocky areas in arid desert scrublands, grasslands, desert plains, and desert mountain ranges from sea level to elevations of ¢.2330 m.

Food and Feeding. Diets of Cactus Deermice include mesquite ( Prosopis, Fabaceae) beans, berries ( Celtis sp., Cannabaceae), various fruits, seeds, flowers of shrubs, chollas fruits ( Opuntia spp., Cactaceae), green vegetation, and insects.

Breeding. In some regions, the Cactus Deermouse reproduces year-round, peaking in April-October, but reproduction is affected by hot and dry periods. Gestation is 21 days. Litters have 5-8 young, and females have 1-3 litters/year. Under laboratory conditions, they can reportedly have up to twelve litters per year.

Activity patterns. The Cactus Deermouse is nocturnal and adapted to arid conditions. It survives on water obtained from food items. It enters torpor when ambient temperatures exceed 30°C and resumes normal activity when temperature drops to 15°C or less.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Nevertheless, all island subspecies (avius, cedrosensis, cinereus, collatus, insulicola, polypolius, and tiburonensis) are considered endangered in Mexico.

Bibliography. Brylski (1990a), Hafner et al. (2001), Hall (1981), Hoffmeister (1986), Jameson & Peeters (1988), Luévano & Mellink (2014c), Meserve (1976), Musser & Carleton (2005), Riddle, Hafner & Alexander (2000), Veal & Caire (1979).