Chipmunk (Tamias striatus)
Chipmunks are members of the same family of animals as the
larger tree squirrels (the family Sciuridae). There is one species
of eastern chipmunk (Tamias striatus) and more than 20 species of
western chipmunks (Eutamias spp.) spread throughout the United
States and Canada. The eastern chipmunk is found throughout much of
the eastern United States to the Mississippi; the western species
take up where the eastern leaves off and cover the rest of the
continent. The chipmunk prefers open deciduous woodlands, forest
edges, brushy areas, bushes, stone or concrete walls, around houses
or in cemeteries. The chipmunk is a reddish brown on top, with
white belly fur. It has one white stripe, boarded by two black
stripes, starting at the side of the head and continuing to the
rump. These strips are parallel, and on both sides of the body. It
has two lighter white stripes down the back, which are much thinner
than the side stripes. The tail is brown, with varied shades of
black near the end. The chipmunks ears are small but prominent, and
face forward. The eyes are small, and set on the sides of the head.
The head tapers to a point at the mouth. The chipmunks mouth is
small, but its cheeks can expand to three times its head size. An
adult chipmunk is 8 1/2 to 11 1/2 inches in length. Its tail is
approximately 4 inches in length. The widest part of the body is
around the shoulder area, about 1 1/2 inches across. The adult
chipmunk weighs approximately 2 1/2 to 5 ounces.
There is very little difference between the male, and female, in
both colors or weight. Mating occurs in early Spring, and there is
one litter per year. An average of 3 to 5 young are born in May,
there have been reported litters as large as ten. The Chipmunk is a
social animal, in that both the male and female raise the young.
The Chipmunk is a ground dwelling mammal, digging tunnels or
burrows, about two inches in diameter. The entrance to the tunnel
system is next to a solid object, such as a tree stump, large rock,
or post. Secondary exits are often in open areas, and there are no
dirt piles around the hole. This makes it difficult for predators
to find. The chipmunk digs with its front paws, which have four
sharp claws on each. The dirt is pushed to the surface, and then
carried away in the animals cheeks. The tunnel system can be as
long as thirty feet in length, with several interconnecting
passages. Tunnels are normally two to three feet below ground, this
depth varies with weather conditions. Most burrows have several
sleeping areas, as well as food storage areas. The sleeping area,
or nest is enlarged and filled shredded leaves to make a
comfortable bed. Food is normally stored in the lowest tunnels, to
keep it cool, and fresh.
The chipmunk hibernates from late Fall to early Spring, waking to
eat every two weeks or so. They may occasionally appear on the
surface during the Winter, but will not stay long especially if
there is snow on the ground. The chipmunks diet consists of nuts,
seeds, and grains. They will climb a tree to harvest acorns,
hickory nuts, and/or Hazel nuts, but they are not as agile in the
trees as their squirrel cousins. The chipmunk prefers to forage on
the ground when ever possible. The chipmunk spends almost the
entire day foraging, and storing food. At times this is done from
Sunrise to Sunset, and it is not unusual for them to harvest a
bushel of nuts in a three day period. While the chipmunk is
herbivorous, it will eat small vertebrates, such as snails, or
slugs. It does not however search out this food. Chipmunk's in an
Urban environment, will take handouts from Humans. This can include
a wide variety of items from pastries, to pizza. They do not store
these foodstuffs, but they do seem to enjoy the novelty of Human
food.
A chipmunk in the wild can live up to seven years. Many die in
their first year, do to lack of food, or poor planning for the
Winter. Young animals may come to the surface, without thinking
about what predators may be waiting for them, and end up as dinner.
The chipmunks primary enemies are foxes, weasels, Bob Cats, badgers
and snakes. Birds such as Hawks, Eagles, and Owls, can take many on
the run over open ground. House cats, are very successful hunters
in Urban areas, and can be considered the Chipmunks worst enemies.
The Chipmunk communicates by both sounds, and gestures. Their
vocabulary is not large, with about thirty distinguishable
combinations. These can be loud, shrill "chip-chip-chip" sounds to
softer, and slower "chuck-chuck" sounds. When combined with body
gestures such as tail waving, they can effectively communicate with
others of their species.
The Chipmunk is in the Ground Squirrel Family, and probably
evolved from a common ancestor which lived in North American
sometime in the Eocene epoch, 54 to 37 million years
ago.