Chipmunks are small members of the Sciuridae family, weigh between 1 and 5 ounces, and are about the size of a teacup. They resemble squirrels but live in burrows rather than trees, although some may take over abandoned birds' nests.
Chipmunks are omnivores, and their diet includes fruits, nuts, seeds, insects, bulbs and the occasional baby mouse or bird, causing some bird species to avoid building their nests near chipmunks. Chipmunks' cheeks have pouches and expand up to three times the size of their heads to allow them to store food while gathering more.
Chipmunks hibernate in winter, but they wake periodically and slowly eat stored food instead of burning fat stores. During the deep sleep phase of their hibernation, their heart rate can slow to as low as four beats per minute, and their body temperature can drop to the temperature of the surrounding air, making them hard to rouse.
Chipmunks communicate with various "chip" and "chuck" sounds as well as trills. Their mating call is a shrill, birdlike sound. Male chipmunks are called bucks, female chipmunks are called does, and baby chipmunks are called pups.
Although they usually reside in wooded areas, they sometimes make their homes in residential areas. Burrows near houses may cause structural or foundational damage, and chipmunks sometimes dig up garden bulbs.