WILDLIFE DIVERSITY NOTEBOOK:
Common Name: Eastern chipmunk
Latin Name: Tamias striatus (from the Latin
word striatus meaning furrow-a reference to the stripes down
Description: Chipmunks are small ground-dwelling rodents.
They have characteristic markings that make them easy to distinguish from
other members of the squirrel family. Two white stripes, one above and
one below the eye, adorn the short, round head. Five black lines stripe
the back: two on each side, separated by a white or buff band, which contains
the fifth black stripe, down the middle of the back. The ears are short,
rounded and held erect. The flattened tail is well haired, blackish above,
rust below, and fringed in white or gray. Both sexes are alike in color
and size, measuring 8-1/2 to 9-1/2 inches long and weighing 2-1/2 to 4
ounces. Their front feet are adapted for holding and eating food while
sitting upright. The front teeth are chisel-shaped, a characteristic of
Habitat: Chipmunks inhabit deciduous (hardwood) forests where there
is a thick vegetative understory and old logs or stone ledges. In
open stands with little or no cover, chipmunks are most often found
on rocky hillsides and living in crevices of stone walls. They are
frequently seen in parks and around gardens and lawns.
Natural History: Chipmunks seem more common than other members
of the rodent order because they are diurnal (active during the day).
Most activity, however, takes place during the cooler hours of the
morning and afternoon. Excessive heat and inclement weather will
hamper normal activities. These rodents are highly aggressive toward
intruders, and readily defend the immediate area around their den
entrance. Their defense is more vocal than violent. You have probably
heard the chipmunk’s loud “chuck, chuck, chuck” call.
Chipmunks rarely climb trees except to escape predators or to gather
food. They spend almost their entire lives in an area usually less
than a half-acre. Travel of 75 yards or greater from the den is considered
exceptional. The outer fringes of individual home ranges often overlap
with other chipmunks. Except during the breeding season, chipmunks
are solitary, living in separate dens.
Predators of chipmunks include hawks, minks, raccoons, weasels,
martens, foxes, bobcats, coyotes, red squirrels, cats and large snakes.
In their natural habitat, chipmunks compete with and complement
the natural community of plants and animals. They compete with gray,
red and flying squirrels, grouse, deer, turkeys, mice and other mast-eating
animals for food.
When chipmunks leave excessive amounts of food stored in the ground
there is perhaps less for other wildlife, but forest tree species
are regenerated when these stored seeds sprout.
Chipmunks are omnivorous, feeding on plant and animal material. Acorns,
beechnuts, seeds of woody plants, berries of American Yew, ragweed,
wintergreen, Canada mayflower, clover and wild buckwheat are among
the major plant foods consumed. Sometimes mushrooms, sunflower seeds,
watermelon, apples and squash are also eaten. Animal food consists
of insects, worms, salamanders, star-nosed moles, young mice, small
songbirds or their eggs and frogs.
Chipmunks have specially adapted internal cheek pouches that allow
them to carry large amounts of food at one time. These pouches are
used when caching food for winter consumption and are emptied by
squeezing them with their front feet. On occasion, they eat food
on the spot, often at a favorite stump or rock that becomes littered
with broken nut shells and fruit seeds. Much time is spent in late
summer and fall gathering and storing nuts and other seeds for the
When not occupied with food-gathering or territorial defense, chipmunks
sleep in their underground burrows. Burrow entrances are neat round
holes, usually two inches or less in diameter. They are often located
under a rotten log, stump or rock. From the entrance, the burrow
plunges straight down for a few inches and then descends more gradually
until it levels out at a depth of about three feet.
During burrow excavation, soil is carried away from the entrance
in cheek pouches used to carry food. Because of this, there is little
or no evidence of excavated material from the subterranean burrow
system. Within four or five years, an average chipmunk’s burrow
may be extended to a length of 30 feet, have several openings, and
may contain up to six chambers.
In late October or November, chipmunks retire to their dens, plugging
up the entrance hole. Although they are not true hibernators, some
may sleep for long periods of time during the cold winter months.
They store food rather than fat, and must wake up often to eat. Mild
weather during mid-winter may entice them out of their dens for short
periods of time.
Breeding: Chipmunks emerge to breed in late February
and early March. There are two breeding seasons annually. During the spring
season, the older females, yearlings and females born the previous summer
season will breed. During the summer season, late July to August, yearlings
that did not mate in spring and a few of the three-month-old females may
also breed. Older females may produce two litters per year. Most young
are sexually mature at age one. After a 31-day gestation period, usually
four or five young are born. Young chipmunks are blind and naked at birth.
They spend a month in the burrow system before leaving the den.
Range: They are common from Quebec south to Florida and west to
Louisiana and North Dakota .
Chipmunks are enjoyable to watch, but when they move into an urban
setting they may conflict with man’s interest. They dig up
garden seeds and have been accused of snitching flower bulbs. Chipmunks
get into camps and homes on occasion and can cause limited structural
damage. Burrow entrances in lawns, rock gardens, stonewalls and near
foundations may also be objectionable. In many instances, however,
any disturbance is offset by the pleasing antics of these alert animals.
Factsheet prepared by the DNR Wildlife Diversity Program staff.
Did You Know?
If a gold medal could be awarded to Best Forager,
the chipmunk would be the clear winner. The tiny gatherer can stuff
over 30 husked nuts in its cheek pouches at one time! Some burrows
have been known to be filled with 6,000 nuts that have been collected
during one season.
Chipmunks not only have a main food cache, but
also “emergency” storage areas in case the other is
robbed or damaged.