Xerospermophilus tereticaudus
Creators: name: Wilson, Don E.
name: Thomas E. Lacher, Jr
name: Mittermeier, Russell A.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Sciuridae
Xerospermophilus
Xerospermophilus tereticaudus

description: 222. Round-tailed Ground Squirrel <i>Xerospermophilus tereticaudus</i> <b>French:</b> Spermophile a queue ronde / <b>German:</b> Rundschwanzziesel / <b>Spanish:</b> Ardilla terrestre de cola redonda <b>Taxonomy.</b> Spermophilus tereticaudus Baird, 1858, “Fort Yuma,” Imperial County, California, USA. Four subspecies are recognized. <b>Subspecies and Distribution.</b> X.t.tereticaudusBaird,1858—SNevadaandSECalifornia(USA),andNEBajaCalifornia(Mexico). X.t.apricusHuey,1927—ValledelaTrinidad,NBajaCalifornia(Mexico). X.t.chlorusElliot,1904—CoachellaValley,SCalifornia(USA). X. t. neglectus Merriam, 1889 — S &amp; W Arizona (USA), and NW and coastal Sonora to extreme NW Sinaloa (Mexico). <b>Descriptive notes.</b> Head-body 204-278 mm, tail 60-112 mm; weight 110-170 g. Dorsal pelage of the Round-tailed Ground Squirrel is pale gray to pinkish buff to tawny, and sides, feet, and venter are white to pale buff. Cheeks are white to pale clay. Tail is short and round, similar in color to dorsum on upper surface but drab to buff to cinnamon on ventral side, with black tip. Subspecies apricus is slightly darker and browner. Subspecies chlorus has drabber and less pink dorsum. Subspecies neglectus is darker and has shorter tail. Chromosomal complement is 2n = 36 and FN = 58. <b>Habitat.</b> Sandy low flat deserts, commonly in communities dominated by mesquite (Prosopis, Fagaceae) and creosote bush (Larrea, Zygophyllaceae). It also occurs in urban areas, cemeteries, and parks. <b>Food and Feeding.</b> Diet consists of buds, flowers, leaves, fruits, and seeds of several species of forbs, shrubs,trees, and cacti. It forages on the ground and in the canopy of trees, sometimes storing food items in modest cheek pouches. <b>Breeding.</b> Reproduction of the Round-tailed Ground Squirrel is well timed to capitalize on short period of winter rains that occur in the Mohave and Sonoran deserts. Males emerge from hibernation first and, in some populations, defend territories. Breeding season begins as soon as females emerge, 2—4 weeks after males. Pregnant females can be found in March—June. Gestation lasts 26-35 days, and litters of 1-13 young (averages 4.9-6-5), weighing 2:7-4-4 g. (average 3-7 g), are born in burrows. Females rarely produce a second litter in a year, and multiple paternities within litters are very common, especially in largerlitters. Young are weaned at 5-6 weeks old and emerge from natal burrows 1-2 weeks later. Young become sexually mature at 10-11 months of age. <b>Activity patterns.</b> The Round-tailed Ground Squirrel is diurnal and mostly terrestrial, although sometimes it climbs trees to forage. It is extremely tolerant of heat, being able to forage at temperatures of ¢.45°C, using shade and burrows to thermoregulate. At high temperatures,it can still remain active even if the body temperature increases several degrees. In some locations,it stays active year-round, but throughout most of its distribution, it enters torpor in winter. Torpor lasts 4-6 months for adult females (September—-March) and 7-9 months for adult males (May—January) in some areas. Individuals sometimes overwinter together in nests, but in other seasons, communal nesting is rare. <b>Movements, Home range and Social organization.</b> Juvenile males disperse farther and more often than females, mainly in June. Home ranges of males and females are similar in size, averaging 0-3 ha. Burrows are relatively inconspicuous and lack clear evidence of excavated soil or mound around entrances, which are located at bases of shrubs and rocks or along a wash. Small burrow complexes are sometimes evident. It does not form matriarchal colonies. When alarmed, individuals run into burrows, sometimes alarming others with high-pitched whistles or series of chirps for aerial predators or using foot drumming for snakes. <b>Status and Conservation.</b> Classified as Least Concern on The IUCN Red List. Subspecies chlorus is of special concern in California, USA. The Round-tailed Ground Squirrel is primarily threatened by conversion of deserts to urban and agricultural lands, especially chlorus. Current population trend is stable. It is not hunted or trapped, but it is occasionally poisoned as a pest around human habitation and historic structures due to its burrowing habits. It is presumed to have a large overall population and high tolerance for a variety of habitats. It occurs in protected areas. <b>Bibliography.</b> Ball et al. (2005), Drabek (1973), Dunford (1977a, 1977b, 1977c¢), Ernest &amp; Mares (1987), Hayssen et al. (1993), Thorington et al. (2012), Turkowski (1969), Wooden &amp; Walsberg (2002).
description: Published as part of <i>Don E. Wilson, Thomas E. Lacher, Jr &amp; Russell A. Mittermeier, 2016, Sciuridae, pp. 648-837 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions</i> on page 809, DOI: 10.5281/zenodo.6840226