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Species in this Guide: 28
Earthwatch Field Guide: Mammals of Nova Scotia
Created by: Earthwatch
Eastern Chipmunk  Tamias striatus         View on EOL
Conservation

Conservation Status

Eastern chipmunks are not in danger as their habitat remains extensive. The main threat to their survival is agriculture. Many sciurids are a nuisance to farmers who kill them to save their crops.

(Nowak, 1991)

IUCN Red List: Lower Risk - Least Concern

US Federal List: No special status

CITES: No special status

State of Michigan List: No special status

Jaime Stephens, University of Michigan   CC License: by-nc-sa

Management
Conservation Actions
The range of this species includes several protected areas.
Linzey, A.V. & Hammerson, G.   CC License: by-nc-sa

Threats
Major Threats
There are no major threats to this species.
Linzey, A.V. & Hammerson, G.   CC License: by-nc-sa

Trends
Population
This species is abundant. Depending on the season, population densities may vary from less than one to 15 per acre (Yerger 1953), and sometimes up to 30 per acre.

Population Trend
Stable
Linzey, A.V. & Hammerson, G.   CC License: by-nc-sa

Overview

General Description
Eastern chipmunks are found in forests, but also in suburban gardens and city parks, as long as there are rocks, stumps, or fallen logs to provide perching sites and cover for burrow entrances They dig complex burrows with many entrances and chambers as well as short escape tunnels, and each chipmunk defends a small area around its burrow, threatening, chasing, and even fighting with a neighbor who invades the space The chipmunks spend the winter underground, but venture to the surface occasionally on mild, sunny days They enter torpor for a few days at a time, and then arouse to feed on stored nuts and seeds Life expectancy in the wild is slightly more than a year

Sexual Dimorphism: None

Length:
Average: 255 mm
Range: 215-285 mm

Weight:
Average: 130 g
Range: 80-150 g

Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species account CC License: by

Distribution

CC License: by

Physical Description

Morphology

Perhaps the most distinctive characteristic of all chipmunks is their pouched cheeks. The pouches are located in the sides of their mouths and are used to store food. When the pouches are full they can be as large as an entire chipmunk's head.

Eastern chipmunks are larger than most chipmunks. They are reddish brown in color with 5 black stripes on their backs. These stripes are separated by brown, white, or grey fur stripes. They also have white and dark markings around their eyes. The stomach is usually a yellowish brown or white color. Their tails are reddish brown and furry, but not bushy like common squirrels. Like many rodents, Tamias striatus has 4 toes on the front feet and 5 toes on the rear feet.

(Allen, 1987; Nowak, 1991)

Other Physical Features: Endothermic; Bilateral symmetry

Sexual Dimorphism: Sexes alike
Jaime Stephens, University of Michigan   CC License: by-nc-sa

Size
Sexual Dimorphism: None

Length:
Average: 255 mm
Range: 215-285 mm

Weight:
Average: 130 g
Range: 80-150 g CC License: by

Ecology

Habitat
Habitat and Ecology
It prefers deciduous woodlands with ample cover, such as brush piles or logs, rocky forested slopes, ravines. Also found in brushlands and hedgerows. Commonly climbs trees and shrubs. Burrows often open at edge or rock, near base of tree, or under the edge of a building. Nest is generally constructed below ground in an extensive burrow system.

Breeding period is from mid-March to early April. A second breeding period occurs from mid-July to mid-August involving young of the previous year. Gestation lasts 31 days. Litter size is 4-15 (3-5 most often). One to two litters per year. Commonly lives 2-3 years, sometimes 5-6 years.

Home range is less than one hectare, typically 0.08-0.60 ha, largest in early summer and early fall; core area of home range is defended against conspecific neighbours; largest home ranges are those of breeding males; low water availability may result in increased home range size. Individuals may make long movements outside their usual range; non dispersing individuals have lifetime home range lengths of up to at least 0.5 km, and dispersal movements may extend to at least 0.9 km (Roberts 1976).

This species utilizes a wide variety of seeds, fruits, and nuts, some mushrooms and insects. Active during the day. In winter, becomes torpid, with frequent arousals.

Systems
  • Terrestrial
Linzey, A.V. & Hammerson, G.   CC License: by-nc-sa

Trophic Strategy

Tamias striatus eats a wide variety of foods including nuts, acorns, seeds, mushrooms, fruits, berries, and corn. They also eat insects, bird eggs, and sometimes small vertebrates such as young mice.

(Anthony and McSpadden, 1937; Godin, 1997 from Nowak, 1991)

Animal Foods: Birds; Mammals; Eggs; Insects

Plant Foods: Seeds, grains, and nuts; Fruit

Other Foods: Fungus
Jaime Stephens, University of Michigan   CC License: by-nc-sa

Life History and Behavior

Behavior

Eastern chipmunks are usually solitary animals that defend small territories around their burrows. There is considerable competition during the mating season for estrus females, but even if a male outcompetes his comrades the female may reject him by biting him and chasing him out of her burrow.

Although Tamias striatus are solitary animals, they have been seen gathering to "sing," or make noise in chorus. They also make a variety of other noises. The name chipmunk comes from the noise "chip, chip, chip" commonly made by these furry animals.

Many kinds of sciurids hibernate during the cold winter months. eastern chipmunks, however, do not hibernate continuously through the winter, nor do they "fatten up" before retreating to their burrows. They keep large stores of food in their burrows and build nests on top of this treasure. During the winter months they wake up periodically and snack on their stored nuts and seeds.

(Allen, 1987; Anthony and McSpadden, 1937; Nowak, 1991)

Key Behaviors: diurnal; motile; sedentary; solitary; territorial
Jaime Stephens, University of Michigan   CC License: by-nc-sa

Life Expectancy
Maximum longevity: 9.5 years (captivity) Observations: These animals have been known to live at least 2-3 years in the wild (Ronald Nowak 1999). One specimen lived 9.5 years in captivity. Another specimen of unknown sex lived over 9 years at London Zoo but could have been older because the exact date of birth is not known (Richard Weigl 2005). CC License: by

Reproduction

Tamias striatus has 2 breeding seasons. This is unusual among sciurids. One season begins in February and lasts until April, the second begins in June and ends in August. They do not form monogomous pairs. Females are in estrus for 3-10 days. The gestation period is 31 days and the usual litter size is 4 to 5, although litters as large as 9 have been found. Young eastern chipmunks do not appear above ground for 6 weeks after they are born. Both male and female eastern chipmunks reach sexual maturity at about 1 year old.

(Allen, 1987; Anthony and McSpadden, 1937; Nowak, 1991)

Key Reproductive Features: Iteroparous; Seasonal breeding; Gonochoric/gonochoristic/dioecious (sexes separate); Sexual; Fertilization; Fertilization :: Internal; Viviparous

February-April, June-August

Young are cared for in the nest by their mother until they are weaned at about 6 weeks old. Soon after that they disperse from their mother's range.

Parental Investment: Altricial; Female parental care
Jaime Stephens, University of Michigan   CC License: by-nc-sa

Show/Hide iNaturalist Observations Map for this species. Source: iNaturalist