The Uinta ground squirrel (''Urocitellus armatus''), commonly called a "chisler" and ''Potgut'' in northern

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

,Noble, Katie
"Animal of the Week: What is a Potgut?"
''The Green Life'', 13 April 2011. Retrieved 24 February 2019. is a species of

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...

native to the western

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

Description

The Uinta ground squirrel is a moderately sized

ground squirrel Ground squirrels are members of the squirrel family of rodents ( Sciuridae), which generally live on or in the ground, rather than trees. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known ...

, measuring in total length. They weigh about when they emerge from hibernation, a figure that steadily increases until they are ready to hibernate again in the fall. Their fur is brown to cinnamon in color, being paler on the underside and grey on the sides of the head and neck. The tail is buff with a grey underside, as distinct from the

ochraceous Ochre ( ; , ), or ocher in American English, is a natural clay earth pigment, a mixture of ferric oxide and varying amounts of clay and sand. It ranges in colour from yellow to deep orange or brown. It is also the name of the colours produced ...

or reddish color found in closely related species such as Belding's or

Wyoming ground squirrel The Wyoming ground squirrel (''Urocitellus elegans'') is a species of rodent in the family Sciuridae. It is endemic to the Northwestern United States The Northwestern United States, also known as the American Northwest or simply the Northwe ...

s. Females have ten teats.

Distribution and habitat

First described from the

Uinta Mountains The Uinta Mountains ( ) are an east-west trending chain of mountains in northeastern Utah extending slightly into southern Wyoming in the United States. As a subrange of the Rocky Mountains, they are unusual for being the highest range in the c ...

, the squirrels are found in

Wyoming Wyoming () is a state in the Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the s ...

west of the

Green River Green River may refer to: Rivers Canada * Green River (British Columbia), a tributary of the Lillooet River *Green River, a tributary of the Saint John River, also known by its French name of Rivière Verte *Green River (Ontario), a tributary of ...

, in southwestern

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...

, eastern

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyomi ...

, and northern and central

. They inhabit open areas, such as meadows, pasture, and shrub- steppe habitats, at elevations between . There are no recognised subspecies. Spermophilus armatus

Behavior

Uinta ground squirrels are primarily herbivorous, and mostly eat grass, seeds, and the leaves of

forb A forb or phorb is an herbaceous flowering plant that is not a graminoid (grass, sedge, or rush). The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory. Typically these are dicots without woo ...

s, along with a small amount of earthworms and discarded human food. The exact composition of the diet changes throughout the year. Their most common predators are coyotes, badgers, weasels, and raptors. Although they often live in colonies, adults react aggressively towards one another outside of the breeding season, with females being more intolerant than males. Males mark their territories with scent glands in their cheeks, which they rub on the ground, but do not mark the entrances to their burrows. The squirrels greet one another by sniffing, escalating to threat postures and bristling the hair on their tails, and eventually to wrestling, boxing, and chasing if the intruder does not retreat. The squirrels make six distinct vocalisations: chirps, squeals, squawks, trills, growls, and teeth clattering. These are used primarily as a means of gaining attention, and all are used in aggressive interactions between individuals. However, chirps are also used to warn of aerial predators, and trills to warn of predators on the ground, with squirrels hearing them either adopting an alert posture or running for their burrows. Uinta ground squirrels are only active for a few months each year. Adult males wake from hibernation around mid March, but may wait a few weeks before emerging, depending upon the weather. Females emerge slightly later, followed by female and then male yearlings. Adults return to their burrows to hibernate between late July and mid August, with juveniles following about two weeks later. During their active periods the squirrels are diurnal.

Reproduction

Females enter

estrus The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after sexual maturity in females and are interrupted by anestrous ...

for a single afternoon each year, about two to four days after emerging from hibernation. They mate underground, and each male may mate with several females. Gestation lasts 23 to 26 days, and results in an average litter of five young, which are born in early May. Yearling females typically have less opportunity to mate, because they emerge from their burrows later, and give birth to smaller litters than older females when they do mate. The young are weaned at about 22 days of age, and emerge from the burrow at around the same time. Although they are still small, weighing only around , the mother almost completely abandons them after weaning, and they disperse to establish their own territories over the next two to three weeks. They can live for up to seven years in the wild.

References

External links

*LaValle, A. 2000. "Spermophilus armatus" (On-line), Animal Diversity Web. Accessed December 25, 2007 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Spermophilus_armatus.html. {{Taxonbar, from1=Q1768499, from2=Q21729942 Urocitellus Endemic fauna of the United States Fauna of the Rocky Mountains Fauna of the Western United States Mammals of the United States Mammals described in 1863