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Harris's antelope squirrel (Ammospermophilus harrisii ) is a species of rodent in the family Sciuridae. It is found in Arizona and New Mexico in the United States, and in Sonora in Mexico. They are adapted to hot weather conditions including a technique called "heat dumping". They have a wide-ranging diet, including both vegetation, insects, small rodents and carrion.




antelope chipmunk



Harris's antelope squirrels are rodents that are often mistaken for chipmunks. These antelope squirrels have distinctive markings on their grey fur, with brown highlights on the sides and legs and a white strip down the side of the torso and encircling their eyes. In the winter their fur grows longer and becomes softer than in the summer.


Harris's antelope squirrels are found in the Southwestern United States, specifically in Arizona and the southwest of New Mexico. The range extends outside the US into Mexico into the northwest of the state of Sonora. These animals inhabit different types of desert habitats which include deserts with cacti and desert shrubs. They also can be found in open plains with gravel and sand.


Harris's antelope squirrels are diurnal being active during the day, including midday hot hours. They do not hibernate and remain active above ground during the year. These squirrels are solitary and meet only during the breeding season. They often climb cacti to scan the territory. Harris's antelope squirrels live in burrows that are often found under various shrubs. They also locate their shelters around rock-bound hills, where they can easily take shelter when necessary. In order to protect themselves from the heat of the desert these little rodents carry their tails over their bodies providing shade. They also use a heat reduction method where individuals move into shaded positions and lie spread eagled against the ground. This method is called a "heat dumping". In order to communicat with each these animals produce trill sounds and stamp their forepaws as alarm signs.


Little is known about the mating system in Harris's antelope squirrels. Their breeding season takes place between February and March although mating can take place between December and June. The gestation period lasts 30 days, and females usually have one litter per year with an average of 6 pups. Young are born with their eyes closed and weigh around 3.6 grams. Their eyes open between 4 and 5 weeks after birth and pups are ready to leave their nest for the first time. Young are weaned at 7 weeks and grow to adult size at around 217 days after birth. Both males and females reach reproductive maturity during the first year.


According to IUCN, the Harris's antelope squirrel is locally common and widespread throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.


Eastern chipmunks and 13-lined ground squirrels are both rodents. They have brown, grayish-brown or reddish-brown fur and are generally similar in size. Chipmunks are usually about 10 inches long, while ground squirrels range from 6 inches to 12 inches.


The most telltale difference between the two is the presence of stripes on their heads, or lack thereof. While both are striped, only 13-lined ground squirrels have stripes that extend to their heads. Only the bodies of eastern chipmunks are striped.


Where you see them can also be telling of whether you are seeing a ground squirrel or a chipmunk. Ground squirrels prefer grassy areas such as yards, cemeteries, golf courses and pastures, and they generally avoid wooded areas. Chipmunks, on the other hand, prefer wooded areas and forests and are also often seen along the edges of wooded areas and in yards with plenty of trees and shrubs.


Both chipmunks and ground squirrels are active during the day, and both are busy at this time of the year as they prepare to hibernate for winter. But only the ground squirrel is a true hibernator, spending all but three to four months a year underground, according to the Missouri Department of Conservation. Chipmunks hibernate as well, but not in the truest sense. They spend most their time during winter underground sleeping in their burrows, but they wake to eat every few days.


One key difference between the two is that only chipmunks store food for winter. They'll gather nuts and seeds to store in their burrows to feast on during winter. Ground squirrels do not wake during their hibernation, so they have no need to create food stores. Instead, during the fall they double their body weight to increase their fat stores to live off during winter, the Missouri Department of Conservation reports.


While chipmunks and ground squirrels can be hard to tell apart, they are easy to distinguish from another common relative: tree squirrels. With their big, bushy tails, tree squirrels can be readily identified.


Taxonomy.--The San Joaquin antelope squirrel is one of five species of antelopesquirrels. Members of the genus Ammospermophilus are confined to desert, aridsteppe, and open shrubland communities in the southwestern United States andnorthern Mexico. Ammospermophilus nelsoni was described by Merriam (1893) as amember of the genus Spermophilus; the type specimen was from Tipton, Tulare County,California. A. nelsoni also has been placed in the genus Citellus. Taylor (1916)distinguished the northern populations as a subspecies, A. nelsoni amplus, but A.nelsoni currently is considered to be monotypic (Hall 1981, Hafner 1981).


Description.--The San Joaquin antelope squirrel (Figure 56) has a typicalground-squirrel shape: tiny, rounded ears, and streamlined, fusiform (spindle-shaped) body with relatively short legs and tail. The tail has laterallyprojecting thick fringes of hairs, and is usually held cocked or curled over theback. The upper parts are colored buffy-tan with a light stripe along the sides.The underside of the tail is light grayish or whitish. Individuals range fromabout 218 to 240 millimeters (8.5 to 9.4 inches) in length (Hall 1981), and adultsweigh from about 130 to 170 grams (4.6 to 6.0 ounces) (Williams 1980).


Identification.--The San Joaquin antelope squirrel can be distinguished from theco-occurring California ground squirrel by much smaller size; shorter, less bushytail with a flattened shape rather than the bottle-brush shape of the Californiaground squirrel; and the presence of a light-colored stripe along the sides of thebody. Many people think antelope squirrels are chipmunks, but antelope squirrelslack the light and dark stripes on the face and the light and dark stripes on theback, which are characteristic of western chipmunks (Tamias spp.).


Historical Distribution.--The historical distribution of the San Joaquin antelopesquirrel included the western and southern portions of the Tulare Basin, SanJoaquin Valley, and the contiguous areas to the west in the upper Cuyama Valley andon the Carrizo and Elkhorn Plains (Figure 57). They ranged from western MercedCounty on the northwest, southward along the western side of the San Joaquin Valleyto its southern end. They were distributed over the floor of the San JoaquinValley in Kern County and along the eastern edge of the Valley northward to nearTipton, Tulare County (Hall 1981, Williams 1980). San Joaquin antelope squirrelsrange in elevation from about 50 meters (165 feet) on the San Joaquin Valley floorto about 1,100 meters (3,600 feet) in the Temblor Mountains. Antelope squirrelsare not common above about 800 meters (2,600 feet) on the ridges and plains west ofthe San Joaquin Valley proper (Williams 1980, D.F. Williams unpubl. data). Thearea encompassed by the distribution records prior to cultivation was approximately1,398,600 hectares (3,456,000 acres). Grinnell and Dixon (1918) wrote that SanJoaquin antelope squirrels were unevenly distributed and occurred in abundance inonly a few localities; one ws in the Lokern and Elk Hills region of western KernCounty.


Current Distribution.--Extant, uncultivated habitat for San Joaquin antelopesquirrels was estimated in 1979 to be 275,200 hectares (680,000 acres) (Williams1980). This estimate encompassed the land occupied by towns, roads, canals,pipelines, strip mines, airports, oil wells, and other developments. None of thebest habitat described by Grinnell and Dixon (1918) remained. Only about 41,300hectares (102,000 acres) was rated as fair to good quality, supporting from 3 to 10antelope squirrels per hectare (1 to 4 per acre). Antelope squirrels had beennearly eliminated from the floor of the Tulare basin, and existed mainly inmarginal habitat in the mountainous areas bordering its western edge. Substantialpopulations were found only in and around Lokern and Elk Hills in western KernCounty, and on the Carrizo and Elkhorn Plains in eastern San Luis Obispo County.


Since 1979, San Joaquin antelope squirrels have disappeared from many of thesmaller islands of habitat on the Valley floor, including Pixley National WildlifeRefuge, Tulare County; Alkali Sink and Kerman Ecological Reserves, Fresno County;and several areas within the Allensworth Conceptual Area of Tulare and KernCounties (Williams 1980, Harris and Stearns 1991, D.F. Williams unpubl. observ.,Endangered Species Recovery Program unpubl. data).


Food and Foraging.--San Joaquin antelope squirrels are omnivorous. The amount andtype of food consumed are mostly dependent upon availability. The squirrels eatgreen vegetation, fungi, and insects more often than seeds, even when seeds arerelatively abundant (Hawbecker 1975, Harris 1993). Vegetation and seeds of filareeand red brome are the main food plants (Hawbecker 1953). Insects, principallygrasshoppers, are eaten regularly when available. Seeds of shrubs such as ephedraand saltbush also are staples. Seeds and insects may be necessary in the diet assources of protein. When seeds and grasshoppers are scarce, antelope squirrels eatharvester ants (Hawbecker 1975). During spring, especially during severe drought,San Joaquin antelope squirrels eat large quantities of ovaries and developing seedsof ephedra (D.F. Williams unpubl. observ.). 041b061a72


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