Much of the information available about antelope ground squirrels is about a species other than A. interpres. Davis (1960) and Best (1999) were the best sources.
Perception Channels: tactile ; chemical
In some cases different species of antelope ground squirrels are being displaced by farms and settlements, which alter their habitat, forcing them to shift their range to non-traditional areas (BISON). Global warming could also be playing a role in the shifting ranges (Cameron, 2001).
IUCN Red List of Threatened Species: least concern
In some areas A. interpres can become a nuisance by raiding crops, but is controlled by various poisoning methods (Walker, 1983; BISON).
Negative Impacts: crop pest
Ecosystem Impact: disperses seeds
A. interpres has a largely vegetarian diet consisting of fruit and seeds from various plants, as well as insects. It has been found to collect food using its cheek pouches and store it in the den and under rocks (Davis, 1960; Best, 1999). In the spring individuals eat a large number of succulents and other vegetation (Best, 1999). A study of a related species, A. leucurus found that species to be omnivorous, eating arthropods and some vertebrates, depending on the season (Bradley, 1968). Another study has shown that succulents are important in the diet of A. leucurus, in order to maintain body moisture in the arid climates inhabitated by that species (Hudson, 1962).
Common foods eaten include: yucca, juniper, salt grass, prickly pear fruits, cholla fruits, mesquite, sotol, creosote bush and insects.
Animal Foods: insects
Plant Foods: seeds, grains, and nuts; fruit
Primary Diet: herbivore (Frugivore , Granivore )
Ammospermophilius interpres occurs on the Chihuahauan plateau of the southwestern United States (Best, 1999), mainly Texas and New Mexico, and in north-central Mexico. It is distinct from A. leucurus, which lives in Oregon, California, and New Mexico (Walker, 1983; Davis, 1960; LTER; Best, 1999).
Biogeographic Regions: nearctic (Native )
A. interpres are characteristic of sparsely vegetated areas. They seems to prefer lowland areas like valleys or low hills and have been seen perched on boulders or short junipers. They are seen primarily in rocky areas and less often in flat sandy areas (Walker, 1983; Davis, 1960; Best, 1999). They dig multi-chambered dens, and they use rock crevices and abandoned dens of other animals as their dens. They normally locate these dens in a cut bank or at the base of a large object such as a bush or a rock. Often the den has more than one entrance. The nest inside the den is lined with bits of fir and feathers, dried grass, and any other soft material the squirrel finds (Davis, 1960; Best, 1999). Canyons and rocks seem to be important in determining their range (Best, 1999).
Range elevation: 540 to 1830 km.
Habitat Regions: temperate
Terrestrial Biomes: desert or dune
A. interpres average 226 mm in length with males weighing between 94 and 121 g. and females between 84 and 115 g (Davis, 1960; Best 1999). The coat is course in texture with light gray-brown to red brown coloring and a white stripe on each side extending from the shoulder to the base of the tail. The stripes are surrounded by darker portions of the main coat color. The eyes are outlined by white fur. The legs have reddish fur (Best, 1999). The tail has three black bands on the dorsal side. Near the body it is black, but the distal two thirds is grey (Best, 1999). The under parts including the tail are white in the summer and gray in the winter. A. interpres generally holds its tail over its back, exposing the contrasting white ventral fur. It has small external ears and ten mammae (Walker, 1983; Davis, 1960; LTER; Best, 1999).
Range mass: 84 to 121 g.
Average length: 226 mm.
Other Physical Features: endothermic ; bilateral symmetry
In its range A. interpres is so common that it is an important food source for many predators, including humans (Best, 1999).
Breeding generally starts in February, continuing through June (LTER). After a gestation period of about 29 days a litter of five to fourteen is born. Occasionally a female will rear two litters in a year, but little is known about the reproductive cycle of A. interpres (Walker 1983, Davis 1960; Best, 1999).
Breeding season: February - June
Range number of offspring: 5 to 14.
Average gestation period: 29 days.
Average weaning age: 1 months.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
The young remain in the mother's nest about a month until they are a quarter grown, then start venturing out and eating solid food. They do not hibernate, so they need not store extra fat during their early development (Davis 1960, LTER; Best, 1999).
Parental Investment: altricial ; female parental care
