Extreme suppression of aboveground activity by a food-storing hibernator, the eastern chipmunk (Tamias striatus)

Abstract

Eastern chipmunks ( Tamias striatus (L., 1758)) capitalize on pulsed production of storable seed from masting trees by accumulating large, long-term larder hoards in their burrow. Since this species does not accumulate fat, hoarded food is the sole source of energy used during hibernation and inactive periods. Because hoards can be very large, they offer chipmunks the possibility of forgoing aboveground foraging when seeds or nuts are not abundant on the forest floor. Here, we present evidence that at least 82 chipmunks in two different populations interrupted aboveground activity for 9–11 months when mast was not available. A large hoard of American beech ( Fagus grandifolia Ehrh.) nuts established during the preceding year appeared to allow these chipmunks to cease foraging for almost a full year when food availability was particularly low. This extended period of inactivity is among the longest reported for a hibernating mammal, and demonstrates complex interactions between past, current, and future resource availability in shaping the seasonal activity patterns of food-storing hibernators.