Eastern Chipmunk, Tamias striatus
Common Names: eastern chipmunk
Species: Tamias striatus
General Description The eastern chipmunk is reddish brown in color with five black stripes along its back. Between both of the outer pairs of black stirpes lies a white band. The underside is white and the feet are brown. The chipmunk ranges from 4-7 inches in length with a 2-4 inch tail and weighs up to 5 ounces. A distinctive trait of all chipmunks is their pouched cheeks which serve as storage while the chipmunk forages. Eastern Chipmunks have two fewer grinding teeth than most other chipmunks as well as only two teeth in the upper jaw.
Geographical Distribution and Habitat Requirements Tamias striatus are found throughout New Brunswick forests, these chipmunks do not exist north of the treeline in Canada. Eastern chipmunks mostly inhabit developed decidous forests however they also enjoy brushy coniferous forests. They like open areas with an abundance of sunlight, logs, stumps and rocks which characterize ideal locations for their burrows. The eastern chipmunk is also found throughout the eastern United States.
General Biology Eastern chipmunks are omnivourous and have a diet which consists primarely of fruits, seeds and nuts, however they have also been know to eat insects, earthworms, flowers and berries. These foraging mammals use their front paws, incisors and tongue to maniplulate their food and store it inside their cheek pouches while continuing to collect food. They are most busy during the autumn season as they are collecting food for the upcoming winter. Although the eastern chipmunk spends most of its time foraging on the ground it is also know to climb quite well.
The chipmunk is a solitary, diurnal mammal and is seen above ground after sunrise and returns to its burrow at sundown. The eastern chipmunk is not a true hibernator, but instead it enters short periods of torpor. While it is in these states of torpor it rolls up into a ball and tucks its head between its hind legs while its tail lies over its head and shoulder. The chipmunks wake up from time to time over the winter season to consume some of the food it has stored during the fall and then returns to its state of torpor. During the late winter the eastern chipmunk begins to wake quite frequently and can be seen exiting their borrows for some fresh air. These burrows can have several entrances with a combination of many tunnels and can be up to 30ft. in length. Since chipmunks are known as territorial mammals they become very defensive and will protect a fifty foot radius around their burrow entrances.
A home range of about 0.04 to 1.26 ha exists for the eastern chipmunk and depends mainly on the abundance of resources. Home ranges often vary with age and sex, therefore adults have larger ranges then the young and males larger then females Two breeding seasons exist within the eastern chipmunks’ lifestyle. One in the spring lasting from early Febuary until April, and the second occurring in the summer from June until August. It was studied that differences in female body mass were observed based upon breading season, resulting possibly from the timing of the chipmunk’s torpid periods during the winter. Adult males are very competitive as well as agressive during the mating season and often will fight over the female. Female Tamias striatus are pregnant for about 30 days, at which time they give birth to a litter of 4-7 young. Infant eastern chipmunks remain underground in the burrows for a period of 6 weeks upon which they leave the burrow and are then on their own. The Tamias striatus reaches maturity after a period of one year and has a lifespan of about 1.3 years.
Conservation The Eastern chipmunk has a fairly stable ranking in terms of conservation status. It is a common mammal and is not threatened by its environment. They are friendly animals and plentiful in parks, camping regions and tourist attrations which can be directly linked to the province’s increase in tourism. The chipmunks’ foraging characteristic makes them significant in the distribution of seeds and plants.
Interesting Facts The Eastern Chipmunk’s name, Tamais striatus, originates from Tamais meaning, the treasurer, pertaining to the foraging behaviour of the chipmunk, and striatus meaning, striped, pertaining to the stripes on the eastern chipmunk’s back. Also the term chipmunk arose from the sound “chip, chip, chip” which is quite often heard from these small animals.