Tamias is Greek for "storer," a reference to the animals' habit of collecting and storing food for winter use. The genus includes twenty-five recognized species, with one species, T. sibiricus, in northeastern Asia, one, T. striatus, in eastern North America, and the rest native to western North America.
Some authors have recently suggested that Tamias should be subdivided into three genera, corresponding to currently recognized subgenera Tamias, Eutamias, and Neotamias. This usage, however, has not been widely adopted.
The common name originally may have been spelled "chitmunk" (from the Odawa word jidmoonh, meaning "red squirrel"; c.f. Ojibwe, ajidamoo). However, the earliest form cited in the Oxford English Dictionary (from 1842) is "chipmonk". Other early forms include "chipmuck" and "chipminck", and in the 1830s they were also referred to as "chip squirrels," possibly in reference to the sound they make. They are also called "striped squirrels", "chippers", "munks", "timber tigers", or "ground squirrels", though the name "ground squirrel" usually refers to members of the genus Spermophilus. Tamias and Spermophilus are only two of the 13 genera of ground-living sciurids.
Eastern chipmunks mate in early spring and again in early summer, producing litters of four or five young twice each year. Western chipmunks only breed once a year. The young emerge from the burrow after about six weeks and strike out on their own within the next two weeks. Chipmunks have an omnivorous diet consisting of grain, nuts, birds' eggs, small frogs, fungi, worms, and insects. At the beginning of autumn, many species of chipmunk begin to stockpile these goods in their burrows, for winter. Other species make multiple small caches of food. These two kinds of behavior are called larder hoarding and scatter hoarding. Larder hoarders usually live in their nests until spring. Cheek pouches allow chipmunks to carry multiple food items to their burrows for either storage or consumption.
These small mammals fulfill several important functions in forest ecosystems. Their activities harvesting and hoarding tree seeds play a crucial role in seedling establishment. They consume many different kinds of fungi, including those involved in symbiotic mycorrhizal associations with trees, and are an important vector for dispersal of the spores of subterranean sporocarps (truffles) which have co-evolved with these and other mycophagous mammals and thus lost the ability to disperse their spores through the air.
Chipmunks play an important role as prey for various predatory mammals and birds, but are also opportunistic predators themselves, particularly with regard to bird eggs and nestlings. In Oregon, Mountain Bluebirds (Siala currucoides) have been observed energetically mobbing chipmunks that they see near their nest trees.
Chipmunks construct expansive burrows which can be more than 3.5 m in length with several well-concealed entrances. The sleeping quarters are kept extremely clean as shells and feces are stored in refuse tunnels.
Tamias striatus - Eastern Chipmunk
Tamias striatus striatus
Tamias striatus doorsiensis
Tamias striatus fisheri
Tamias striatus griseus
Tamias striatus lysteri
Tamias striatus ohioensis
Tamias striatus peninsulae
Tamias striatus pipilans
Tamias striatus quebecensis
Tamias striatus rufescens
Tamias striatus venustus