resources are scarce. They are agile animals, and have been recorded running at speeds of up to in natural conditions. Predators include hawks, owls, and mustelids. Least chipmunks spend the winter in burrows and also scatter-hoard food in numerous concealed pits beneath logs and similar cover. Burrows consist of a single chamber about across and tunnels in diameter, averaging in length. They have two to four entrances, often concealed by nearby rocks, and are typically about below the surface. During the summer they may construct temporary nests in trees from leaves and grass, or appropriate hollows made by woodpeckers. Least chipmunks do not hibernate, or put on excess fat in the fall. Instead, they survive the winter by entering torpor for long stretches of time, waking to eat food cached in the burrow. How much of each winter they spend below ground in this manner depends on the latitude, varying from late November to mid March in Michigan to mid October to late April in northern Manitoba. Reproduction Females enter estrus within a week of emerging from their burrow in the spring, and mating typically takes place between March and May. Gestation lasts 28 to 30 days, with a single litter of three to seven young being born each year; females who lose their first litter soon after birth may, however, sometimes be able to breed again in the same year. The young are born hairless and blind, measuring about in length, and weighing . They are able to stand and open their eyes at 27 days, and are weaned at 36 days. They are sexually mature at one year, but do not always breed until their second year. They can live for up to six years in captivity. Gallery References Neotamias Fauna of the Great Lakes region (North America) Mammals of Canada Mammals of the United States Least concern biota of North America Least concern biota of the United States Mammals described in 1839 Taxa named by John Bachman