Eastern chipmunk distribution extends throughout south-eastern Canada and into the southern United States. This small rodent is most commonly found in woodland areas (preferably deciduous) with good sheltering underbrush, rocks, and fallen logs. Its name derives from the Algonquian ‘Adjidaumo’ (pronounced a-chit’-a-mauk) in reference to its habit of descending trees head first.
Eastern Chipmunk Description
The squirrel family’s smallest member, the eastern chipmunk (Tamias striatus) has white under parts and overall russet colouring with grey, white, and black stripes on its back. Its dark eyes and rounded ears are outlined with distinctive white markings. The male and female, alike in markings and colour, measure about nine inches (22 cm) from tip of pointed nose to tip of short, flat, hairy tail.
Typically, the chipmunk sits upright while biting food that it holds in dexterous front paws. Using its sharp upper and lower incisors, the chipmunk removes seeds or nuts from pods or shells, and then stuffs them into cheek pouches which expand until they are almost the size of the animal’s head. When the pouches are full, the chipmunk deposits the contents in its burrow or a shallow hole that it covers over.
Omnivorous Woodland Rodent
The omnivorous eastern chipmunk spends most of its day gathering and storing food. Though it gathers most of its food by ground foraging, this energetic animal quite easily climbs to harvest nuts and berries from trees. While seeds and nuts are its primary foods, earthworms and insects are included in its summer diet, and only non-perishables are stored for winter.
It also enjoys small carrots from the garden, tiny flower buds such as those of Johnny-jump-ups, and appreciates a gift of fresh apple cores. By October, each eastern chipmunk has stored enough food in its burrow (approximately 8 lbs. or 3.6 kg) for winter survival.
Eastern Chipmunk Breeding
Most eastern chipmunks in Canada breed only once during the season, while in the southern U. S., they often produce two litters. Early in the spring, the male chipmunk emerges from his burrow and immediately starts foraging for food. In northern regions, mating occurs during April or May near the female’s burrow when she appears a week or so later.
After a thirty-day gestation period, the female rears the litter of about five young without the male’s help. Young eastern chipmunks are born blind and hairless. Their ears open after about 28 days, and their eyes after about 31 days. The young chipmunks start to leave the female's burrow at age five to seven weeks, and grow rapidly to adult size by late September when each has its own burrow prepared.
Tunnels and Chambers
Solitary by nature, each chipmunk constructs its own burrow tunnels with entrances well hidden under tangled shrubs, fallen logs or rock bases. Using its cheek pouches, it carries the excavated earth out of the tunnel and away from the entrance. As it continues digging the burrow during its entire life, the chipmunk could have a tunnel 40 feet (12 m) or more in length with several chambers and entrances.
The nesting chamber, usually separate from others, is insulated with shredded leaves, grasses and/or fluffy seed heads and the winter supply of seeds and nuts is stored in an accessory chamber. In one such burrow complex examined by scientists, there was no evidence of the resident chipmunk’s body waste. Small caches of uneaten seeds covered with vegetation in gardens or on the forest floor become the eastern chipmunk’s contribution to the spread of trees, plants, and shrubs.
Eastern Chipmunk Winter Survival
After about three months’ constant activity that begins in midsummer, the chipmunk has accumulated a good supply of food, and during late October (December in southern areas) retires to its burrow. Not a true hibernator, it enters brief periods of torpor, awakens, eats some food, then sleeps again, and may venture outside during a mild period in March.
Similar to birds, the eastern chipmunk delivers a variety of calls. When startled, it lets out a ‘chip’ sound before disappearing into the underbrush or other hiding place. Very often, it will call with a high-pitched, repetitive ‘chuck’ sound from a safe perch while observing and warning of a predator approaching. Its most-common vocalization is a ‘chip-chip’ that some observers mistake for a bird’s call.
During an average life span of four years the eastern chipmunk is an entertaining creature as it scurries through woodlands and enjoys special garden features.
Sources:
Mammals of the Canadian Wild by Adrian Forsyth, Camden House Publishing 1985
The Mammals of Canada, by A. W. F. Banfield, University of Toronto Press 1974
The Squirrels of Canada by S. E. Woods Jr., National Museum of Natural Sciences, Ottawa, 1980
Kathleen Airdrie - Kathleen has thirty years' freelance writing experience covering history, biographical profiles, environmental and social issues
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