Urocitellus richardsonii
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
Urocitellus
Urocitellus richardsonii

description: 202. Richardson’s Ground Squirrel <i>Urocitellus richardsonii</i> <b>French:</b> Spermophile de Richardson / <b>German:</b> Richardson-Ziesel / <b>Spanish:</b> Ardilla terrestre de Richardson <b>Taxonomy.</b> Arctomys richardsonii Sabine, 1822, “Carleton-House,” Saskatchewan, Canada. This species is monotypic. <b>Distribution.</b> Northern Great Plains in S Alberta, S Saskatchewan, and S Manitoba (Canada), S to Montana, North Dakota, NE South Dakota, W Minnesota, and extreme NW Iowa (USA). <b>Descriptive notes.</b> Head-body 283-337 mm (males) and 264-318 mm (females), tail 66—88 mm ale) and 55-82 mm (females); weight 290-745 g (males) and 120-590 g (females). Dorsal pelage of Richardson’s Ground Squirrel is fuscous cinnamon to gray-buff, and head and neck are ocherous to cinnamon buff. Eyes are encircled by a white to buff ring, and snout can be light gray. Ventral pelage, as well lowersides, are clay to buff to cinnamon, and tail is grizzled charcoal to black on dorsal side and cinnamon buff to clay in ventral side. Chromosome complement of Richardson’s Ground Squirrel is 2n = 36, FN = 64. <b>Habitat.</b> Grasslands, pastures,fields, and croplands. <b>Food and Feeding.</b> Diet of Richardson’s Ground Squirrels consists mostly of leaves, flowers, and seeds of both natural occurring species and cereal plantations. When available, insects are readily consumed. Cannibalism of road-killed animals was also reported. <b>Breeding.</b> Mating occurs 3-5 days after emergence of females, and male-male competition is intense during the two or three weeks of breeding season. Many males die due to injuries and loss offat reserves. Females mate with several males, and a copulatory plug forms after each mating. After a gestation of ¢.22-23 days,a litter of 3-11 young, with an average weight of 6-8 g (4:4-9-6 g, n = 147) each,is born within a grass-lined nest chamber in burrow. Young emerge from natal burrow at c¢.28-30 days old, are weaned 1-2 weeks later, and are sexually mature at one year. Females produce only onelitter a year. <b>Activity patterns.</b> Richardson’s Ground Squirrel is diurnal and hibernates in burrows for c.6-8 months. Emergence begins in March or April, with adult males appearing first and adult females emerging about c.2-3 weeks later. Adult males hibernate in June, followed by adult females soon after, but juvenile females only hibernate in August and juvenile males remain active and reach adult size as late as October. <b>Movements, Home range and Social organization.</b> Males disperse from their natal area during their first year oflife, although females remain in or near the natal area. Related females are amicable within the kin cluster, but aggressive to unrelated individuals, chasing them away. Burrows consist of extensive networks of passages and entrances, with multiple chambers that extend to a depth of 1 m. Individuals hibernate alone, but often share the burrow system with other individuals. Males store seeds within the nest chamber to consume in preparation for next spring’s mating season. Rigors of mating season result in male life spans that rarely exceed two years, whereas females live up to six years. Alarm calls of Richardson’s Ground Squirrel are a long shrill burst that elicits vigilance for terrestrial predators and a short “chirp” that causes surrounding individuals to escape to cover in response to aerial predators. Number of callers in a population indicates severity of the potential threat, and location and order ofcalls indicate direction of avian predators. <b>Status and Conservation.</b> Classified as Least Concern on The IUCN Red List. Current population trend is stable and there are no major threats to Richardson’s Ground Squirrel. Because it consumes cereal grains,it is considered a pest and is poisoned in some agricultural areas. There are several protected areas within the distribution of Richardson’s Ground Squirrel. <b>Bibliography.</b> Hayssen et al. (1993), Michener &amp; Koeppl (1985), Michener &amp; McLean (1996), Risch et al. (2007), Swenson (1981), Thompson &amp; Hare (2010), Thorington et al. (2012).
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 800, DOI: 10.5281/zenodo.6840226