South Dakota’s small handful of eastern chipmunk records sits in the state’s eastern prairie-pothole country, near Sand Lake and Waubay national wildlife refuges. This chipmunk needs mature deciduous woodland with brushy or rocky ground cover, habitat that’s naturally scarce on the glaciated prairie and mostly limited to river-bottom timber and planted shelterbelts. South Dakota sits at the far northwestern edge of the species’ range, which lines up with NatureServe’s S2 imperiled rank for the state.
Where it does find cover, an eastern chipmunk digs an elaborate burrow system with hidden entrances, stuffing its expandable cheek pouches with nuts and seeds to carry back and store. It forages by day and gives sharp, repeated alarm calls from cover whenever a hawk or fox gets too close.
Every one of South Dakota’s records falls between March and July, with none reported the rest of the year. That fits a chipmunk that spends the coldest months underground in a torpor-like sleep, waking periodically to feed from its stores rather than staying fully active through winter.
