Round-tailed Ground Squirrel

activity

Activity patterns. 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.

Sciuridae

biology_ecology

Habitat. 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.

Sciuridae

biology_ecology

Movements, Home range and Social organization. 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.

Sciuridae

breeding

Breeding. 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.

Sciuridae