Spermophilus lateralis fossils have been found in late Pleistocene deposits. Possibly due to more moisture in the past, the range in which the fossils of this species have been found is larger than their current range. They have been found in many caves throughout Wyoming, Colorado, Idaho, Montana, California, Nevada, and Arizona. Their presence in Ventana Cave, Pima Co., Arizona, is interesting because this site is over 260 km south and at an elevation 1,400 m lower than the nearest extant population.
(Bartels and Thompson, 1993)
Perception Channels: tactile ; chemical
These squirrels are common in the areas where they occur.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
Spermophilus lateralis can have a negative impact on the timber industry. In the fall, coniferous seeds make up a large portion of their diet, and S. lateralis can harm reforestation efforts by eating newly sprouted conifer seeds. They have little impact on agriculture because of habitat selection.
Spermophilus lateralis is a vector for zoonotic diseases, and they are the main mammalian reservoir for Colorado tick fever, a non-lethal, tick-born viral disease. They are also vectors for the plague. Although campers enjoy feeding the squirrels, care should be taken not to get bitten or inhale dried fecal matter.
(Bartels and Thompson, 1993; Encyclopedia Britanica, online, 2001)
Negative Impacts: crop pest
Golden-mantled ground squirrels have little positive economic importance to humans. They do however, provide amusement and enjoyment for many campers as they can become quite tame, living at campgrounds and taking food from eager campers hands. (Bartels and Thompson, 1993)
Spermophilus lateralis is a primary consumer, and is therefore responsible for converting plant energy into a form useable by predators in the animal kingdom. There are many different types of predators that prey upon S. lateralis (listed under Predation). Golden-mantled ground squirrels probably affect predator populations and reproduction, depending upon how heavily any predator species relies on S. lateralis as a food source.
Spermophilus lateralis may also regulate populations of birds, lizards, and other small mammals upon which it preys.
Tunneling behavior can aerate the earth.
Competition between S. lateralis and other rodents can occur over food sources, which can therefore cause a negative effect on other rodent populations.
(Bartels and Thompson, 1993)
Ecosystem Impact: disperses seeds; soil aeration
Spermophilus lateralis is omnivorous. Individuals of this species dig up and consume underground fungi, locating it by smell. The nuts of Pinus are a dietary staple. They also eat other nuts, acorns, seeds, forbs, flowers, bulbs, fruit, shrubs and leafy greens. Animal matter consumed consists of adult and larval insects, birds and eggs, including mountain bluebirds (Sialia currocoides) and Oregon juncos (Junco oreganus), young microtus, voles, entrapped yellow-pine chipmunks (Tamias amoenus), lizards (Sceloporous gracilis), and carrion, including road-killed conspecifics.
(Bartels and Thompson, 1993)
Animal Foods: birds; mammals; reptiles; eggs; carrion ; insects
Plant Foods: leaves; roots and tubers; seeds, grains, and nuts; flowers
Other Foods: fungus
Primary Diet: omnivore
Spermophilus lateralis is found in Canada and the United States. It ranges from southeast British Colombia and southwest Alberta, into the western United States as far east as western Colorado and down to northwestern New Mexico and southern California.
(Bartels and Thompson, 1993; National Wildlife Federation, 2000)
Biogeographic Regions: nearctic (Native )
Spermophilus lateralis is found from 1,220 m in the northern Sierra Nevada mountains of California, up to 3,965 m at Pike's Peak, Colorado. This species occurs in mixed coniferous forests of the Klamath, Cascade and Sierra Nevada ranges. Golden-mantled ground squirrels are found up to and above the timberline, provided that there is enough cover for them. Forest-edged meadows and rocky slopes can be occupied, as well as chaparral habitat in southern California. Spermophilus lateralis is abundant in campgrounds in where these squirrels enjoy human handouts.
(Bartels and Thompson, 1993)
Range elevation: 1,200 to 3,965 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: chaparral ; forest ; scrub forest ; mountains
Lifespan has been recorded by Bartles and Thompson (1993) as an average of 7 years in the wild, and 5 years in captivity. This seems odd, as captive animals, not facing dangers of predation and food shortage, typically live longer than their wild counterparts. The difference in wild and captive lifespans reported by Bartles and Thompson may relfect differences in populations of S. lateralis, which vary greatly in habitat, hibernation pattern, and sociality. Also, it seems likely that their reported average for wild gound squirrels does not take into account juvenile mortality, much of which must remain unknown to observers as the young are hidden away in burrows.
Average lifespan
Status: wild: 7 years.
Average lifespan
Status: captivity: 5 years.
Range lifespan
Status: wild: 7 (high) years.
Spermophilus lateralis is a strikingly colored ground squirrel. This species has a golden-red mantle that extends from the head down over their shoulders. One white stripe, bordered by two black stripes, extends horizontally down the body, similar to chipmunks. Although chipmunks have a white stripe through their eyes, Spermophilus lateralis has a whitish fur eye ring and no facial striping. The back is gray, brownish or buff, and their undersides are whitish or yellowish-gray. The tail is brownish-black above, and reddish brown on the underside. Winter pelage is grayer and the mantle is duller. The species is sexually dimorphic, with males having a brighter red mantle as well as a significantly larger brain size.
These squirrels range in weight from 120 to 394 grams, and in length from 235 to 295 mm.
(Bartels and Thompson, 1993; Iwaniuk, 2001; National Wildlife Federation, year unknown)
Range mass: 120 to 394 g.
Range length: 235 to 295 mm.
Other Physical Features: endothermic ; bilateral symmetry
Average basal metabolic rate: 0.967 W.
Golden-mantled ground squirrels are primary consumers, and are eaten by many different secondary consumers. Predators include various diurnal and nocturnal raptors, including red-tailed hawks and northern goshawks; mammals like coyotes, bobcats, skunks and various weasles; and snakes.
Predator avoidance behaviors include alarm calls accompanied by tail jerks. Spermophilus lateralis and yellow-bellied marmots respond to each others' alarm calls for predator warnings. Golden-mantled ground squirrels will ascend rocks and logs as lookout stations, occasionally sitting upright for a better view. They will also dive into the nearest cover or hole when a predator is spotted or an alarm call heard. Spermophilus lateralis keeps a series of burrow openings around their feeding areas to escape predation.
(Bartels and Thompson, 1993; Shriner, 1998)
Known Predators:
As in many ground squirrels, males are polygynous. After emergence from hibernation, they compete with each other to establish territorial boundaries. Male territories encompass the territories of several females. When females emerge from hibernation, they typically mate with the male on whose territory they are found.
Mating System: polygynous
Copulation begins after adults emerge from hibernation, from March to May. Males emerge from hibernation in breeding condition. They compete with one another during this time, establishing territories. Females follow shortly, 2 to 3 weeks after male emergence.
The gestation period is 26 to 33 days, with young being born from May to the beginning of September, depending on altitude. Most litters arrive from May to late June. Females have one to two litters per year. Litter size ranges from two to eight pups, averaging five. Litter size is larger at lower elevations.
Like many rodents, S. lateralis pups are born hairless except for tiny whiskers and hairs on their head. Their toes are fused together and their ears are closed. They are able to squeak and squirm around, but have little control over their body position. After a week, their fur has grown enough that their markings are visible. Vibrissae are also longer by this time, and they are able to right themselves. After two weeks, teeth erupt, ears open, toes separate and they utter their first adult sounds. Between days 20 to 30, upper incisors erupt, eyes open and grooming begins. They begin to eat solid food at around a month old, at which time their growth rate is rapidly accelerated. Pups leave the natal burrow when they are at least 25% of the adult body size, and are weaned sometime after they are at least 29 days old.
(Bartels and Thompson, 1993; Bihr and Smith, 1998; National Wildlife Federation, year unknown)
Breeding season: Breeding time varies with altitude, usually occurring immediately after hibernation.
Range number of offspring: 2 to 8.
Range gestation period: 26 to 33 days.
Range weaning age: 29 (low) days.
Range age at sexual or reproductive maturity (female): 12 (high) months.
Range age at sexual or reproductive maturity (male): 12 (high) months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Average birth mass: 6.26 g.
Average number of offspring: 5.12.
The mother cares for the offspring as they grow inside the natal burrow. Young are highly altricial, but develop rapidly. Nests are built of grasses, dried leaves and shredded bark in underground burrows that can extend up to 30m shallowly underground. Studies have shown that S. lateralis prefers to have burrow entrances under significantly larger than average rocks or stumps
Pups are altricial and require extensive maternal care, which declines when they are weaned between 24 to 32 days. Care for the pups is provided by the female only, and that declines 2 to 3 weeks after the pups leave the nest (when at about 25% of adult body size), after which the female becomes antagonistic towards her offspring. Females and males reach sexual maturity within the first year.
(Bartels and Thompson, 1993; Bihr and Smith, 1998; National Wildlife Federation, year unknown)
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
The golden-mantled ground squirrel (Callospermophilus lateralis) is a ground squirrel native to western North America. It is distributed in the Rocky Mountains of British Columbia and Alberta, and through much of the western United States.[1]
This ground squirrel is generally about 23 to 29 cm (9.1 to 11.4 in) in length. The weight range for adults is between 120 and 394 grams (0.26 to 0.86 lbs.)[2] It has whitish or yellow-gray underparts. The tail is brown to black with buff edges and a yellowish to reddish underside. It has pale rings around the eyes. The "mantle" across the shoulders is tawny to reddish, with males having a deeper reddish tinge. This species is distinguished from similar ground squirrels by a black-bordered white stripe down each side of the back and is distinguished from similar looking chipmunks by its lack of facial stripes.[3]
Some authors describe many subspecies of this taxon.[4]
This species occurs in forests, chaparral, meadow margins, and sagebrush, especially in areas with many rocks or forest litter that provides shelter. It is associated with many kinds of coniferous trees, aspen, and manzanita.[3]
It is omnivorous, feeding on pine nuts, acorns, herbs and shrubs, fungi, many kinds of insects, eggs, young birds, lizards, carrion, and human foods when available.[3] This species caches food near its burrow, especially during the late summer and fall.[3] The squirrel has also been known to "beg" for human food at the wildlife urban interface.[5]
This species hibernates over the winter. During the summers they gain extra weight in order to prepare for hibernation.[5] The squirrels hibernate in dens that can reach up to 100 feet in length although they are typically shallow in depth.[6] The breeding season commences when males and females emerge from hibernation in the spring. Most broods are born in July. A female has two to eight young per litter, with an average of five. There is no paternal care of the offspring. Juveniles resemble adults by 40 days of age. The life span of this ground squirrel is up to about seven years.[3]
Most adults are independent, rarely cooperating, and usually competing for resources. They may assemble at sites with abundant food but develop a group hierarchy. Adults reside alone in burrows, creating nests for hibernation or rearing of young. This species has been known to nest in structures, such as roofs.[3] This species becomes vocal when it feels threatened, making squeaking noises or growling. However, it is generally not a very vocal species.[5]
Predators of this squirrel include snakes, foxes, weasels, and bears.[1] It may carry the Rocky Mountain wood tick, a vector of Rocky Mountain spotted fever and other diseases.[1]
This is a common and widespread species that is not considered to be threatened.[1]
The golden-mantled ground squirrel (Callospermophilus lateralis) is a ground squirrel native to western North America. It is distributed in the Rocky Mountains of British Columbia and Alberta, and through much of the western United States.
