The Idaho ground squirrel is one of the largest of the ground squirrels. Its back is dark reddish-gray from a mixture of yellowish-red banded and black unbanded guard hairs. It has an eye ring of an off-white color. Young Idaho ground squirrels molt, usually from May to early June, but adults do not molt and tend to have a longer coat. There are two subspecies living in Idaho: the northern Idaho ground squirrel, as well as the southern Idaho ground squirrel.
Idaho ground squirrels occur in west-central Idaho only. Their habitat consists mainly of meadows that primarily feature grasses and broad-leaved forbs, and mostly in the vicinity of coniferous forest.
An Idaho ground squirrel is a diurnal mammal and is active above ground for around five months before it goes into its underground burrow around late July or early August, usually emerging in late March or early April. It lives at higher elevations. These animals construct three kinds of burrow: nest burrows, auxiliary burrows, and hibernation burrows. The nest burrow is where the young are raised. The auxiliary burrow has no nest and is built far away from nest burrows. The burrow used for winter hibernation consists of one tunnel leading to the single nest chamber. Openings to burrows are usually under shrubs, rocks or fallen timber, but can also be found in open meadows. The males do not live close by females or the young. The females are more social than the males, because of their interactions with their young.
Idaho ground squirrels are polygynandrous (promiscuous) which means that both males and females breed with multiple mates. Males emerge from hibernation 1 to 2 weeks before the females. Males compete with each other for access to females, heavier males being able to displace lighter ones. Once a male has found a female, he guards her until mating occurs, which is in early spring, once the females have emerged from hibernation. A female will produce one litter each year, usually in late May or early June, after a gestation period of about 50 to 52 days. There are two to seven young in a letter, the average being five. Pups disperse 2 to 3 days after emerging from the burrows where they were born. Idaho ground squirrels are sexually mature at about 2 years of age.
The main threat to Idaho ground squirrels is fragmentation and loss of meadow habitat as a result of forest regrowth. Replacement and poisoning of native grasses with tall introduced grasses also have had large negative effects on the species. Further threats include domestic livestock grazing, off-road vehicle use (which may destroy burrows), competition from Columbian ground squirrels (possibly excluding Idaho ground squirrels from the deeper soils that provide better conditions for hibernation), and recreational shooting. In addition, recreational housing developments could be a major conservation challenge in the near future.
According to the IUCN Red List resource, the total adult population size appears to be at least several thousand individuals. According to the Fish and Wildlife Service resource, the total number of the northern Idaho ground squirrel subspecies is about 450 to 500 individuals at 29 population sites: national forest lands (Council/New Meadows Ranger Districts): 14 sites; private lands: 12 sites; municipal property (town of Bear, Idaho): 1 sites; State of Idaho lands: 2 sites. Overall, Idaho ground squirrels’ numbers are decreasing today and they are classified as Endangered (EN) on the IUCN Red List.
Idaho ground squirrels may affect populations of hawks, badgers, prairie falcons, and weasels, as items of prey.