Chipmunks are related to squirrels and are recognizable by their chubby cheeks. There are 25 species of chipmunk, and all but one live in North America. One of the more common chipmunks is the eastern chipmunk, which lives throughout eastern North America and prefers deciduous and mixed forests. They are most commonly seen in old-growth hardwood forests with some open space.
A chipmunk burrow is a maze of interconnected tunnels 2 inches in diameter that run from 12 to 30 feet long. A chipmunk burrow usually has one unobstructed entrance and several others that are blocked with leaves. The tunnels lead to a nest chamber measuring about 6 to 10 inches in diameter with more tunnels to food galleries nearby. Chipmunks generally reuse burrows dug by other mammals but will add to the system using its forefeet to dig and will transport the loose soil in its cheek pouches.
Interesting Chipmunk Facts
Chipmunks are omnivores and eat seeds, nuts, tubers, fruits and fungi as well as invertebrates such as insects, worms and snails. Occasionally they will kill and eat frogs and small birds, especially nestlings. They prefer red and sugar maple seeds, yellow trout lily bulbs and black cherries, but their favorite food is beechnuts. A chipmunk can fit up to 32 husked beechnuts in its cheeks at one time and may collect 5,000 to 6,000 by the end of autumn. They are diurnal creatures and leave their burrows only during daylight periods. They are less active when it is hot, windy or rainy.
They are not good climbers, which requires them to primarily forage nuts from the ground. They may however climb an adjacent tree with a rough bark to gain access to the smooth-barked beech tree to reach their favored beechnuts from the canopy. After jumping into the beech tree, they will bite off clusters of nuts and then scurry to the ground to collect them.
Chipmunks spend most of the winter in their burrows, using the food stores collected over the warmer months. If there are warm periods over the winter, they may emerge and forage for seeds above ground.
They are primarily solitary creatures with a home range of about 1/2 to 1 acre, and their territory may overlap with other chipmunks. With the exception of core areas such as dens, chipmunks are not territorial. They are vocal creatures and make trilling, chucking or chipping sounds to announce predators or make it known that they are occupying an area. Males may chase or fight each other during mating season to gain access to females.
In March or April and maybe again in July or August, a female gives birth to one or two litters of two to nine young after a gestation period of 31 days. The males are not involved in rearing their young. Newborn chipmunks are 2 1/2 inches long, weigh about 0.1 ounce and are toothless, blind and naked. They open their eyes at about 30 days and emerge from the burrow about 10 days later. Shortly after, they are weaned when their mother either moves them to another burrow or moves out herself. They go off on their own about two weeks later.
The typical chipmunk lifespan is roughly two to three years, though some may live to be eight. They are preyed upon by owls, raccoons, wild canine and feline species, and even red squirrels.
The Western Red-Tailed Chipmunk
The red-tailed chipmunk lives in western North America. More arboreal than other chipmunk species, they live in underground dens or in tree nests in rocky, brushy habitat among dense coniferous forests and at the forest’s edge or in open brushy habitats created by fire where downed wood is present. They also have been known to build dens in rock crevices and log piles.
Like the eastern chipmunk, the red-tailed chipmunk’s diet consists mostly of seeds, fruits, mushrooms, insects, and bird’s eggs and nestlings. They also spend much of the winter in their den, with occasional appearances during warm spells. Though these chipmunks have only one litter a year, in July, like the eastern chipmunk, the young stay with their mother for about a month and a half. However, the female red-tailed chipmunk sometimes will move the brood to a tree nest before the weaning period. They are fully grown at about two months and are sexually mature at one year. Red-tailed chipmunks that survive the first 16 months tend to live to eight years of age in the wild.
- Connecticut Department of Energy and Environmental Protection: Chipmunk
- College of Environmental Science and Forestry: Eastern Chipmunk
- Virtual Nature Trail at Penn State New Kensington: Eastern Chipmunk
- Oregon Wildlife Institute: Conservation Assessment for the Red-Tailed Chipmunk (Tamias Ruficaudus Simulans) in Washington