Chipmunks and squirrels are not the same species, but they belong to the same biological family of rodents, Sciuridae. The confusion arises because a chipmunk is technically a type of squirrel, belonging to this larger family. Chipmunks are small, striped rodents that spend most of their time on the ground. In contrast, the animals most commonly called squirrels, such as the gray squirrel, are larger, bushy-tailed climbers. The differences between these two common animals are apparent in their classification, physical appearance, and daily habits.
The Taxonomic Relationship
Both chipmunks and squirrels belong to the family Sciuridae. This classification means they are related, but they are not the same species. The Sciuridae family is expansive, including tree squirrels, ground squirrels, flying squirrels, marmots, and prairie dogs.
Chipmunks are typically grouped into the genus Tamias and are considered ground squirrels. The gray squirrels commonly seen in parks belong to a different genus, such as Sciurus, which contains tree squirrels. This distinction highlights the evolutionary split between the predominantly ground-dwelling chipmunk and the tree-dwelling squirrel.
The broad term “squirrel” covers all members of the Sciuridae family, making a chipmunk a specific kind of squirrel. Their separate genera define them as distinct types of animals.
Key Physical Distinctions
Chipmunks are significantly smaller than squirrels. The Eastern chipmunk (Tamias striatus) reaches a length of only 8 to 10 inches, including the tail, and weighs only a few ounces. In contrast, common tree squirrels, like the Eastern gray squirrel, can measure up to 20 inches long and weigh over a pound.
The defining physical trait of a chipmunk is its conspicuous pattern of dark and light stripes running down its back and across its face. Chipmunks typically display five dark stripes separated by lighter stripes, extending to their head and eyes. Most tree squirrels have a uniform coat of gray, brown, or reddish fur, lacking the detailed striping characteristic of the chipmunk.
Tree squirrels possess a long, extremely bushy tail used for balance when climbing. Chipmunks have a shorter, less voluminous tail. Chipmunks also possess expandable cheek pouches used to transport large quantities of seeds and nuts, a feature generally absent in tree squirrels.
Behavioral and Habitat Differences
Chipmunks are predominantly terrestrial, living on and under the ground. They construct complex burrow systems with multiple tunnels and chambers for nesting and food storage. While they are capable climbers, they forage mainly on the ground and retreat to their underground homes when threatened.
Conversely, the familiar tree squirrel is largely arboreal, spending most of its life in trees. They build nests called dreys high in the branches or utilize tree cavities. Tree squirrels descend to the ground to forage, but they rely on the canopy for safety and nesting.
The way they manage winter also separates them. Chipmunks enter a state of torpor during colder months, waking up periodically to feed on stored food in their burrow’s larder. Tree squirrels remain active throughout the winter, relying on scattered caches of buried food to survive.