Chipmunks are small, active rodents belonging to the squirrel family, Sciuridae, and are found across North America and parts of Eurasia. These animals are easily recognized by their distinct striped pattern and diurnal activity. Chipmunks generally prefer habitats with ample ground cover, such as deciduous forests, woodlands, and brushy areas, where they can find protection among rocks, logs, and stumps. Although they are members of the squirrel family, they are predominantly ground-dwelling and are known for their extensive underground burrow systems.
Overall Size and General Build
Chipmunks are characterized by their small, slender stature. The typical body length, excluding the tail, ranges from about 4 to 7 inches (10 to 18 cm) for most species. The largest species, the Eastern chipmunk (Tamias striatus), can reach a body length of up to 7.5 inches (19 cm) and generally weighs between 1 and 5 ounces (28 to 142 grams).
Their coat ranges in color from a reddish-brown to a grayish-brown, often with a subtle yellowish or reddish patch on the rump, and a lighter, usually white, underbelly. The tail is moderately long, typically measuring 3 to 5 inches, and is hairy but not notably bushy. It is often held upright as the animal moves across the ground.
A distinguishing feature of the chipmunk’s head is the presence of large internal cheek pouches, which are extensions of the oral cavity. These expandable pouches are used exclusively for transporting foraged food items, such as seeds and nuts, back to their underground storage chambers. When empty, the pouches are mostly unnoticeable, but they can swell to nearly the size of the chipmunk’s head when fully packed.
The Defining Stripe Pattern
The conspicuous pattern of dark and light stripes covers the chipmunk’s back and face. Across the main body, the pattern typically consists of five dark stripes running lengthwise from the shoulders toward the rump. These dark stripes are usually black or dark brown and are separated by bands of lighter fur, which are often cream, white, or buff.
The longest dark stripe runs centrally down the midline of the back, flanked by two sets of alternating light and dark stripes. This distinct arrangement of linear markings provides a form of camouflage known as disruptive coloration. The bold lines help to break up the chipmunk’s body outline, making it difficult for predators to recognize the animal’s shape against the dappled light and shadow of the forest floor.
Prominent stripes are also found on the chipmunk’s face, specifically around the eyes. Each side of the face features a dark line running through the eye, often bordered by a lighter, white or buff-colored stripe both above and below it. These facial markings are a key visual trait that differentiates chipmunks from other striped ground squirrels, which typically lack stripes on the head.
Key Differences from Tree Squirrels
Chipmunks are frequently confused with tree squirrels, but several physical and behavioral traits make them easy to distinguish. The most immediate difference is size; chipmunks are significantly smaller, with the largest species weighing only a few ounces. Common tree squirrels like the Eastern Gray Squirrel can weigh over a pound and measure up to 21 inches long.
The tail provides another clear contrast, as the chipmunk’s tail is relatively short, flatter, and far less bushy than the large, prominent, and often cylindrical tails of tree squirrels. Tree squirrels use their full, bushy tails for balance and as a thermal blanket, while the chipmunk’s tail is more modest and often held straight up when it runs.
Behavior and habitat preference also serve as reliable differentiators. Chipmunks are fundamentally ground-dwelling animals that live in elaborate underground burrows. They spend the majority of their time foraging on the ground or on low structures like stumps and logs. Conversely, tree squirrels are predominantly arboreal, spending most of their time climbing and nesting high in trees, only descending to the ground to bury or forage for food.