Chipmunks are small, striped rodents belonging to the squirrel family, Sciuridae, instantly recognizable by the distinct dark and light stripes that run down their backs and across their faces. Their global distribution is confined to the Northern Hemisphere, spanning North America and Asia. This geographical range is home to over 25 recognized species, each adapted to its localized environment.
Continental and Species Range
The vast majority of chipmunk species are concentrated across North America, divided into eastern and western populations. The Eastern Chipmunk (Tamias striatus) is the sole species found throughout the eastern half of the continent, extending from southeastern Canada south through the eastern United States. This adaptable species thrives in deciduous woodlands and urban parks, reaching west to the Great Plains and south into Mississippi and Oklahoma.
In contrast, the western half of North America is home to over 20 species, many grouped under the genus Neotamias. These species are fragmented in their distribution, often occupying specific, high-elevation habitats in mountainous regions across the western United States and Canada. The Least Chipmunk (Tamias minimus) is the most widespread species, occupying the Rocky Mountain region, the western Great Plains, and extending into central and western Canada.
Other western species, such as the Uinta Chipmunk (Tamias umbrinus), are found in discontinuous pockets of high-elevation coniferous forests, ranging from southern Montana and Wyoming down to Arizona and eastern California. The only species found outside of the Americas is the Siberian Chipmunk (Eutamias sibiricus), which occupies a massive tract of land in Eurasia. Its range stretches from the White Sea in northwestern Russia, eastward across Siberia, and south into northern Japan and China.
Micro-Habitats and Burrow Systems
While the continental range defines a species’ overall location, their existence is confined to a specific micro-habitat, typically centered on a burrow system in the ground. Chipmunks seek out environments that offer protective cover, such as the understory of coniferous and deciduous forests, woodland edges, and rocky areas like stone walls or cliffs. Even in urban settings, they exploit ground cover near foundations, brush piles, or beneath the roots of large trees.
The permanent home of a chipmunk is a complex underground network that can extend up to 30 feet in length and reach depths of three feet. The main entrance is a simple, round hole, usually 2 to 3 inches in diameter, which is flush with the ground and lacks a noticeable mound of excavated soil. Chipmunks avoid a dirt pile by carrying the soil out in their cheek pouches and scattering it away from the entrance.
Once inside, the burrow features a central nesting chamber, lined with soft materials like dried leaves, grass, and fur for insulation. Off the main tunnels, they excavate side pockets used for storing cached food and discarding empty seed shells. The system also incorporates narrow drainage tunnels at the lowest points to prevent water from collecting in the main chambers.
Seasonal Adaptation and Location Use
The chipmunk’s location and activity are governed by the changing seasons, particularly the need to survive the winter months. During late summer and fall, the primary focus is intense foraging and caching, which determines the location and size of its winter refuge. They use their cheek pouches to transport large quantities of seeds, nuts, and acorns back to their underground storage chambers.
When cold weather arrives, the chipmunk’s location shifts entirely underground, where it remains for the winter, relying on its cached food supply. Chipmunks are not true hibernators, but enter a state of torpor, during which their body temperature and metabolic rate drop significantly. Unlike true hibernators, they periodically wake up every few days or weeks to access and consume the food they have stored.
In the southern parts of their range, or during mild periods, chipmunks may occasionally emerge above ground on sunny winter days, but their location is predominantly the secure, food-rich burrow. When they emerge in the early spring, the increased activity marks the start of the breeding season. Mating generally occurs outside the female’s burrow, sometimes followed by a second, smaller breeding period in the summer.