Eastern chipmunks are extremely vocal and produce a variety of chips, trills and calls to alert others to the presence of predators or for territory defense. Territorial calls lead to aggressive behavior when another individual is present. High intense chases establish hierarchies among groups of males competing for access to females, individuals display aggressive and submissive postures during these behaviors. Sniffing hindquarters and touching noses provides chemical signals during these interactions. Alarm calls can be costly and the benefits must outweigh the costs to justify such behavior. Eastern chipmunks give three distinct calls: chipping, chucking and trilling. Chipping and chucking are repeated calls lasting up to thirty minutes. Trills are shorter in duration and are given during pursuit by a predator. The other calls are typically given when a predator is spotted.
Eastern chipmunks react to alarm calls by altering their foraging behavior and becoming more alert. After an alarm call, they expend greater energy and spend more time exposed at feeding stations because they decrease the amount of food carried to caches after hearing the call. Eastern chipmunks increase vigilance, run shorter more direct distances and delay emergence from burrows after hearing an alarm call, which suggest that the calls directly affected behavior. Trill vocalizations are complicated and more difficult to understand than the other two types of calls. Adult females are most likely to trill when close (10 m from the burrow) to relatives. Females do not disperse as far as males and have more relatives living close to their burrows. Juvenile females trill at a lower rate than adults, this may indicate their higher predation risk or smaller fitness gain. Males trill farther from the burrow, 100 m or greater. This could be because males are uncertain of kinship and trilling would put an individual at higher risk. Trilling occurs in all active seasons, not just during juvenile emergence, which discounts the hypothesis that trilling is a mechanism of parental care. The primary function of trill calls is likely to warn nearby relatives of predators. This increases an individual’s overall fitness by helping related individuals.
Communication Channels: acoustic ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
Eastern chipmunks are listed as a species of Least Concern according to the IUCN Red List.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Some Sciurids cause destruction to crops in gardens, fields and in food storage areas. Eastern chipmunks are not noted for causing this type of damage.
Negative Impacts: crop pest
Eastern chipmunks are not significantly important to the economy. Eastern chipmunks eat insects and may be helpful in controlling the population of some pest species. They are also easily tamed and can make unique pets.
Positive Impacts: pet trade ; controls pest population
Eastern chipmunks are primarily 'larder hoarders'. Seeds stored in this way cannot establish seedlings and are not beneficial to plant dispersal. However, their occasional scatter-hoarding behavior can be beneficial in seedling establishment. They also are important to spore dispersal for different kinds of fungi. Because of their abundance, chipmunks are a valuable prey item for a variety of species.
Ecosystem Impact: disperses seeds
Dietary staples include fruit, seeds and nuts. This is supplemented with insects, earthworms, slugs, bird’s eggs and mushrooms. Food is transported within cheek pouches located on either side of the mouth. Eastern chipmunks demonstrate food caching behavior throughout the year, but are particularly active in the early autumn to prepare for winter. Eastern chipmunks scatter-hoarder and will leave caches throughout their home range or in one of the rooms their burrow. They do not have the fat stores to hibernate, but instead enter periods of torpor. Chipmunks may arise frequently to feed and during mild winter weather they may forage above ground.
Animal Foods: eggs; insects; terrestrial worms
Plant Foods: seeds, grains, and nuts; fruit
Other Foods: fungus
Foraging Behavior: stores or caches food
Primary Diet: herbivore (Granivore ); omnivore
Eastern chipmunks are widely distributed throughout the eastern United States and southeastern Canada. Their range extends from Nova Scotia, east to Saskatchewan and south to Oklahoma, where they occupy the eastern part of the state. Their range includes eastern Louisiana and the Florida Panhandle. This species does not occupy the peninsula of Florida or the coastal plains region, from Florida to North Carolina. They are not native to Newfoundland, but have been introduced.
Biogeographic Regions: nearctic (Introduced , Native )
In the western portion of their range, eastern chipmunks inhabit wooded areas, river valleys and are interspersed in habitats distant from deciduous forests. This ground dwelling mammal inhabits open deciduous forests where cover is readily available in the form of stumps, logs or rocky outcrops. Their prime habitat is mature beech-maple forests, but they will occupy bushy areas and coniferous forests, however, swampy sites are avoided.
Terrestrial Biomes: forest
Other Habitat Features: urban ; suburban ; agricultural
Most eastern chipmunks survive less than two years, but there are accounts of chipmunks living up to eight years.
Range lifespan
Status: wild: 2 to 8 years.
Average lifespan
Status: wild: 8 years.
Average lifespan
Status: wild: 3.0 years.
Average lifespan
Status: captivity: 8.0 years.
Eastern chipmunks are small rodents with grayish to reddish brown fur and a distinguishing yellowish to reddish patch on their rumps. Their pelage color and pattern varies by geography. Their underparts are white. Their sides and back have five dark stripes; the longest stripe occurs along their midline. Between their dark lateral stripes, there is a narrow white band. Light and dark stripes occur on their face around their eyes. Their tail is hairy, but not bushy and is somewhat flattened. Their rounded ears measure less than 20 mm. Their forefeet have four toes and their hindfeet have five. Eastern chipmunks have large cheek pouches located on either side of their mouth. The stripe along their body distinguishes them from all other rodents except least chipmunks. However, least chipmunks' stripes extend to the base of their tail, whereas, eastern chipmunks' stripes stop before their rump patch. Eastern chipmunks are noticeably larger than least chipmunks, which helps to distinguish between the two species.
Range mass: 66 to 115 g.
Range length: 255 to 266 mm.
Other Physical Features: endothermic ; bilateral symmetry
Average basal metabolic rate: 0.813 W.
Eastern chipmunks are prey for most diurnal predators including weasels, felids and domestic dogs and cats. Large raptors including red-tailed hawks and goshawks also prey on chipmunks.
Known Predators:
Eastern chipmunks are polygamous. During a brief estrous period, females mate with multiple males. Typically females in estrous stay within their home range and males come from outside areas to mate. On average, males travel 170 meters from their burrow to mate.
Mating System: polygynous
Eastern chipmunks produce two litters per year; one in early spring and one in midsummer. Their gestation period lasts 35 days. Litters consist of 2 to 5 altricial young, which are born blind and hairless in underground nests. Litter sizes are dependent on resource availability and the age of the mother.
Breeding interval: Eastern chipmunks have 2 breeding seasons.
Breeding season: One of their breeding seasons begins in February and lasts until April and the second begins in June and ends in August.
Range number of offspring: 2 to 5.
Average gestation period: 35 days.
Average weaning age: 40 days.
Average time to independence: 2 months.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Average birth mass: 3.4 g.
Average gestation period: 31 days.
Average number of offspring: 5.
Average age at sexual or reproductive maturity (male)
Sex: male: 228 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 187 days.
At birth, young weigh just 3 grams. The neonates are weaned 40 days after birth. After weaning, females move to a new burrow, leaving their young in the natal burrow until they disperse. Young become independent two months after birth. Males disperse farther than females. Females stay close to their home burrow with their range sometimes overlapping. Most young do not breed until the spring following their birth.
Parental Investment: female parental care
The eastern chipmunk (Tamias striatus) is a chipmunk species found in eastern North America. It is the only living member of the chipmunk genus Tamias.[4][5][6][7][8]
The name "chipmunk" comes from the Ojibwe word ᐊᒋᑕᒨ ajidamoo (or possibly ajidamoonh, the same word in the Ottawa dialect of Ojibwe), which translates literally as "one who descends trees headlong."[9] First described by Mark Catesby in his 1743 The Natural History of Carolina, Florida, and the Bahama Islands, the chipmunk was eventually classified as Sciurus striatus by Linnaeus, meaning "striped squirrel" in Latin.[10][11] The scientific name was changed to Tamias striatus, meaning "striped steward," by Johann Illiger in 1811.[12]
A small species, it reaches about 30 cm (12 in) in length including the tail, and a weight of 66–150 g (2.3–5.3 oz).[13] It has reddish-brown fur on its upper body and five dark brown stripes contrasting with light brown stripes along its back, ending in a dark tail. It has lighter fur on the lower part of its body. It has a tawny stripe that runs from its whiskers to below its ears, and light stripes over its eyes. It has two fewer teeth than other chipmunks and four toes each on the front legs, but five toes on the hind legs.[14] The chipmunk's appearance "remains consistent throughout life. There is no external difference in appearance between the sexes except the obvious anatomical characteristics of the genitalia during periods of fertility. Molt occurs once or twice annually, during May or June and sometimes again in October. Both albino and melanistic specimens have been observed, but without geographical regularity."[15]
The eastern chipmunk lives in deciduous wooded areas and urban parks throughout the eastern United States and southern Canada. It prefers locations with rocky areas, brush or log piles, and shrubs to provide cover.[16]
The eastern chipmunk can climb trees well, but constructs underground nests with extensive tunnel systems, often with several entrances. To hide the construction of its burrow, the eastern chipmunk is argued by some to carry soil to a different location in its cheek pouches.[17] However, recorded observations of chipmunks carrying soil in their cheek pouches are extremely limited. John Burroughs is noted as having written that "I used to think that the chipmunk carried away the soil in his cheek pouches, and have so-stated in one of my books [Riverby, 1894], but I am now certain that he does not—only his food stores are thus carried."[18] Chipmunks also line their burrows with leaves, rocks, sticks, and other material, making the burrows even harder to see.[17] "The vocal repertoire of the chipmunk consists of five more or less stereotyped sounds: the chip, the chuck, the trills, the whistle or squeal, and chatter."[19] The chipmunks' trill has been measured to occur at the rate of 130 vibrations per minute.[14]
In a six-year study that tracked 59 resident and 49 transient chipmunks on a 1.5 acre study area in Spotsylvania County, Virginia during the late 1970s, chemistry professor Lawrence Wishner significantly contributed to contemporary published research regarding the Eastern Chipmunk's behavior by drawing on his copious, localized observational data. Wishner noted that "it cannot be overemphasized that the uniqueness of this study lies in its continuous day-to-day observation of 108 individual chipmunks for a period of six years."[20]
The chipmunk is mainly active during the day, spending most of its day foraging. It prefers bulbs, seeds, fruits, nuts, green plants, mushrooms, insects, worms, and bird eggs. It commonly transports food in pouches in its cheeks.
The eastern chipmunk defends its burrow and lives a solitary life, except during mating season. In fact, the chipmunk's solitary existence has been noted as "one of the most characteristic behavioral features of the chipmunk," whereas "social interaction of a relatively peaceful nature occurs only during the brief period of courtship and mating, and during the six to eight weeks that the young spend with the mother after birth."[21] Females usually produce one or two litters of three to five young.[14] The two breeding seasons are from February to April and from June to August. During the winter, the chipmunk may enter long periods of hibernation.[22]
Predators of the eastern chipmunk include hawks, owls, foxes, raccoons, snakes, weasels, coyotes, bobcats, lynx, domestic dogs and domestic cats. On average, eastern chipmunks live three or more years in the wild, but in captivity they may live as long as eight years.[14]
Eastern chipmunks are known to be one of many hosts for the parasitic larvae of Cuterebra botflies.[23]
Eastern chipmunk with filled cheek pouches, Cap Tourmente National Wildlife Area, Quebec, Canada
Calling (video)
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Looking to the right
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Descending headlong
Eastern chipmunk peeking out of burrow
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in Guelph, Ontario, Canada
Media related to Tamias striatus at Wikimedia Commons
The eastern chipmunk (Tamias striatus) is a chipmunk species found in eastern North America. It is the only living member of the chipmunk genus Tamias.
