Wyoming ground squirrel
| Wyoming ground squirrel | ||||||||||||
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Wyoming ground squirrel ( Urocitellus elegans ) |
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| Urocitellus elegans | ||||||||||||
| ( Kennicott , 1863) |
The Wyoming ground squirrel ( Urocitellus elegans , Syn . : Spermophilus elegans ) is a species of squirrel from the genus Urocitellus . It occurs in three subspecies in three separate areas in the western United States from Nevada and Idaho through parts of Montana , Wyoming and Colorado to western Nebraska .
features
The Wyoming ground squirrel reaches a head-trunk length of about 20.6 to 21.6 centimeters, the tail is about 7.3 millimeters long and is thus significantly shorter than the rest of the body. The weight is around 280 to 330 grams. It is therefore a small to medium-sized species of the genus with large ears and a comparatively long tail compared to other species. The back color is gray, sand-colored and partly smoky gray with slight speckles. The sides of the head, neck and body are greyish and become more brownish towards the back. The belly is lighter pink, sand or cinnamon in color. The top of the tail is brown to sand in color.
The range of the Wyoming ground squirrel overlaps with that of several other species of the genus with which it occurs sympatric . Compared to the Columbia ground squirrel ( Urocitellus columbianus ), the Wyoming ground squirrel is slightly smaller, and it differs from the Belding ground squirrel ( Urocitellus beldingi ) by its slightly longer tail and less reddish belly color. The Uinta ground squirrel ( Urocitellus armatus ) is less sand-colored underneath and more gray. Compared to the Richardson ground squirrel (Urocitellus richardsonii), the Wyoming ground squirrel is slightly smaller and the two species are differentiated in terms of skull dimensions, compared to the Townsend ground squirrel ( Urocitellus townsendii ) it is larger and has a more cinnamon-colored belly.
distribution
The Wyoming ground squirrel occurs in three separate areas in the western United States from Nevada and Idaho through parts of Montana , Wyoming and Colorado to western Nebraska . One part is in southeast Oregon, Nevada and southern Idaho, another in eastern Idaho to southwest Montana, and the third in northeast Utah, central Colorado, a large part of southern to central Wyoming and the extreme southwest of Nebraska.
Way of life
The Wyoming ground squirrel is diurnal and lives mainly in open areas, mainly in highland meadows and mountain pastures, which are characterized by sagebrush ( Artemisia tridentata ). Urocitellus elegans elegans typically occurs at heights of 1500 meters to above the tree line. Urocitellus elegans aureus can also occur in parts of its range in deeper regions, probably due to competition and displacement by the Uinta ground squirrel .
Like all other species of the genus, the Wyoming ground squirrel is primarily herbivorous and its diet consists primarily of grasses and the leaves of various herbs, but the composition can vary and occasionally insects, especially grasshoppers, and other animal foods are ingested. The daily amount of energy per animal is estimated at around 35.5 kcal . They hibernate in hibernation , which usually lasts from late July to early April. The males begin their hibernation before the females and young animals, which also retreat to the burrows by September at the latest. In the spring, males leave the burrow about a week before the females. The phases of activity of the Wyoming ground squirrel during the summer are mainly in the morning and in the evening, they spend around 21 hours a day in their underground burrow. The animals live in colonies, which mainly consist of closely related animals with their young and in which the individual individuals each inhabit their own burrows. The males leave the colony after weaning. The territories of the males cover 0.2 to 0.4 hectares, the population numbers of the species range from an average of 0.2 individuals to 48 individuals per hectare. Especially during the mating season, these territories are defended against conspecifics. The animals communicate using different chirp sounds and calls of different lengths.
The mating season of the Wyoming ground squirrel begins a few days after the females wake up in spring. They ovulate about 5 days after awakening and are then fertile for about 24 hours; the males are able to reproduce when they wake up. The litter is born in the underground nest and consists of an average of six young animals. You leave the den for the first time after about four to five weeks.
In parts of the distribution area there is competition and displacement with other types of squirrels, especially with the Uinta ground squirrel and the gold-coated ground squirrel ( Callospermophilus lateralis ). While the latter is displaced by the Wyoming ground squirrel, the former can generally prevail and displaces the Wyoming ground squirrel. There is also regional competition for resources with the yellow-bellied marmot ( Marmota flaviventris ) and the American pika ( Ochotona princeps ). Mating and hybrids can occur with the Richardson ground squirrel . The mortality of the animals during the winter is comparatively low, the survival rate is 55 to 100 percent and differs between the males and females. Mortality is higher in young animals. In summer, the survival rate is 31 to 75 percent, here too it is lower for young animals. As predators various predators and birds of prey are documented, including the goshawk ( Accipiter gentilis ) and the Red-tailed Hawk ( Buteo jamaicensis ). Among the parasites, ectoparasites such as various fleas , mites and ticks are documented, and there are also endoparasites such as various Eimeria species. The species is also a potential carrier of plague pathogens ( Yersinia pestis ) and Colorado tick fever .
Systematics
The Wyoming ground squirrel is classified as a separate species within the genus Urocitellus , which consists of twelve species. The species has long been classified as part of the ground squirrel and within the subgenus Spermophilus . After a comprehensive molecular biological investigation, the Columbia ground squirrel was assigned to the now independent genus Urocitellus together with several other species . The first scientific description comes from the American naturalist Robert Kennicott from 1863. He created it on the basis of individuals from Fort Bridger in Uinta County , Wyoming, and described the Wyoming ground squirrel under the name Spermophilus elegans . The species and its subspecies today were partially assigned to the Richardson ground squirrel ( Urocitellus richardsonii ).
Within the species, together with the nominate form, two subspecies are distinguished:
- Urocitellus elegans elegans : nominate form, occurs in northeastern Utah, central Colorado, a large part of southern to central Wyoming and the extreme southwest of Nebraska and southeastern Idaho. It is the smallest and darkest subspecies, the hind feet are very small.
- Urocitellus elegans aureus : This subspecies lives in eastern Idaho to southwestern Montana. The belly side and the underside of the tail are ocher to sand-colored, generally it is lighter than the nominate shape.
- Urocitellus elegans nevadensis : The form occurs in southeast Oregon (possibly extinct there), Nevada and southern Idaho. There is only one known population in Idaho with a few animals in Nevada. The top is brown, more gray, the bottom is dark sand-colored.
Status, threat and protection
The Wyoming ground squirrel is classified as Least Concern (LC) by the International Union for Conservation of Nature and Natural Resources (IUCN). This is justified by the comparatively large distribution area and the assumed frequent occurrence in two of the three distribution areas. The decreases are not so clear that a classification in a different hazard category is justified. Potential threats arise primarily from changes in habitats, in particular the conversion of steppe areas into agricultural land. The animals are also susceptible to the plague, which contributes to a reduction in populations and sometimes to the wiping out of individual colonies. The ground squirrel is seen regionally as a pest and is killed with poison.
supporting documents
- ↑ a b c d e f g h i j k l m Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012, ISBN 978-1-4214-0469-1 , pp. 357-359 .
- ↑ a b c Urocitellus elegans in the IUCN Red List of Threatened Species 2016.1. Listed by: E. Yensen, NatureServe (T. Mabee, G. Hammerson), 2008. Retrieved August 30, 2016.
- ↑ Matthew D. Herron, Todd A. Castoe, Christopher L. Parkinson: Sciurid phylogeny and the paraphyly of holarctic ground squirrels (Spermophilus). Molecular Phylogenetics and Evolution 31, 2004; Pp. 1015-1030. ( Full text , PMID 15120398 )
- ↑ Kristofer M. Helgen, F. Russell Cole, Lauren E. Helgen, Don E. Wilson: Generic Revision in the holarctic ground squirrels genus Spermophilus. Journal of Mammalogy 90 (2), 2009; Pp. 270-305. doi : 10.1644 / 07-MAMM-A-309.1
- ^ Robert Kennicott: Descriptions of four new species of Spermophilus, in the collections of the Smithsonian Institution. Academy of Natural Sciences of Philadelphia Proceedings, 1863; Pp. 157-158. ( Digitized version )
- ↑ a b David A. Zegers: Spermophilus elegans. Mammalian Species 214, 1984; Pp. 1-7. ( Full text ( Memento from March 16, 2016 in the Internet Archive ))
- ↑ a b Spermophilus elegans . In: Don E. Wilson , DeeAnn M. Reeder (Eds.): Mammal Species of the World. A taxonomic and geographic Reference. 2 volumes. 3. Edition. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-8018-8221-4 .
literature
- Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012, ISBN 978-1-4214-0469-1 , pp. 357-359 .
- David A. Zegers: Spermophilus elegans. Mammalian Species 214, 1984; Pp. 1-7. ( Full text )
Web links
- Urocitellus elegans inthe IUCN Red List of Threatened Species 2016.1. Listed by: E. Yensen, NatureServe (T. Mabee, G. Hammerson), 2008. Retrieved August 30, 2016.