chipmunk, (genusTamias), any of 25species of small, striped,terrestrialsquirrels with large internal cheek pouches used for transportingfood. They have prominent eyes and ears, a furrytail, and delicateclaws. All are active only during the day, and all but one are North American, occurring from southernCanada to west-centralMexico. Body length among most species ranges from 8 to 16 cm (3.1 to 6.3 inches) and tail length from 6 to 14 cm (2.4 to 5.5 inches).

Chipmunks are basically pygmy squirrels adapted to exploiting the resources of rocky terrain andforest understories. They scamper along the ground but are also expert climbers. As a group they are an ecologically versatilegenus. Different species can be found fromsea level to 3,900 metres (12,800 feet) inenvironments defined by largerocks, boulders, and cliffs. They inhabit various forest types, from timberline slopes and rock-bordered alpine meadows downward throughconiferous anddeciduous forests to dryscrublands andsagebrushdeserts.

Theeastern chipmunk (Tamias striatus), common to the deciduous forests of easternNorth America, is the largest. Weighing 70–142 grams (2.5–5 ounces), it has a body 14–19 cm (5.5–7.5 inches) long and a shorter tail (8–11 cm [3.1–4.3 inches]). The fur is reddish brown and is broken by five dark brown stripes running lengthwise down the body. These alternate with two gray-brown stripes and two whitish stripes. The smallest chipmunk is theleast chipmunk (T. minimus), which weighs about half as much as the eastern chipmunk. TheHopi chipmunk (T. rufus) lives among thebuttes and canyonlands of theAmerican Southwest and is remarkablyadept at climbing sheer rock faces and overhangs. TheUinta chipmunk (T. umbrinus), which lives in montane forests of the westernUnited States, is much like a tree squirrel in its habits. In addition to denning in burrows, it regularly sleeps and nests intrees, where it sometimes raises young in tree cavities or abandonedbirdnests. The only Old World species is theSiberian chipmunk (T. sibiricus), which ranges from theWhite Sea of northwesternRussia eastward throughSiberia to northernJapan and south toChina.

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The chipmunks’ call is a shrill chirring or chipping. They relishseeds,berries, and tenderplants, but they also eatfungi,insects and otherarthropods, and sometimes carrion. They stuff seeds andnuts into their cheek pouches and carry them to a burrow to be stored for later use. As most chipmunks do not accumulate significantfat during thefall, they depend upon thiscached food during the winter. Although they experience periods oftorpor, chipmunks occasionally emerge on sunny, windlesswinter days. They were not considered to be truehibernators, but studies indicate that the eastern chipmunk’s body temperature ranges from 35 to 41 °C (95 to 105.8 °F) during activity and drops to 5–7 °C (41–44.6 °F) during torpor—a difference that characterizes true hibernators. Two to eight (rarely nine) young are born inspring orsummer after about a month’sgestation. A second litter, usually smaller, is often produced in regions with long summers.

Chipmunks are members of thesquirrel family (Sciuridae) within the orderRodentia. Although mostclassifications acknowledge a single genus of chipmunks,Tamias, some separate the species into the generaTamias,Eutamias, andNeotamias.