Least chipmunks are the smallest of all chipmunks. Body length ranges from 185 to 222 mm (Burt, 1946). Individuals weigh between 42 and 53 g. Females are larger than males in some populations (Berstrom, 1999) There are three dark and two light stripes on the face and five dark and four light stripes along their sides. The middle stripe runs to the end of the tail (Burt, 1946). Dorsal background fur is orangish-brown, and ventral coloration is grayish-white (Kurta, 1995). The tail is bushy and long, ranging from 81 to 95 mm, and is pale brown in color (Hamilton and Whitaker, 1979). (Bergstom, 1999; Burt, 1946; Hamilton and Whitaker, 1979; Kurta, 1995)
Because they hibernate, these chipmunks are heterothermic. However, their body temperature remains relatively constant over short spans of time. There is a lower body temperature when the animal is torpid than when it is active. (Bergstom, 1999)
Other Physical Features: Endothermic; Heterothermic; Homoiothermic; Bilateral symmetry
Sexual Dimorphism: Female larger
>p Source: The Regents of the University of Michigan and its licensors CC License: by-nc-sa
Major threats to these animals include Mustela, goshawks, Cooper's hawks, snakes, Mustela vision, Vulpes vulpes, Lynx rufus, and Martes, as well as domestic dogs and cats. (Baker, 1983; Bergstom, 1999)
Source: The Regents of the University of Michigan and its licensors CC License: by-nc-sa
Highly favorable habitats may contain 30 or more per acre, though average densities typically range from 5 to 15 per acre (Jackson 1961). Home range varies from less than an acre to 4 acres (Banfield 1974).
Source: NatureServe CC License: by-nc
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Source: NatureServe CC License: by-nc
Least chipmunks eat a wide variety of foods. Their diet including nuts, berries, fruits, grasses, fungi, snails, insects, and possibly some small birds and mammals. From April through October, much of a chipmunk's time is spent foraging. Least chipmunks forage both on the ground and in trees at heights up to 9 m (Kurta, 1995). Cheek pouches allow individuals to carry multiple food items back to their burrows, where they are either eaten or stored for future use. (Baker, 1983; Bergstom, 1999; Kurta, 1995)
Animal Foods: Birds; Mammals; Carrion; Insects; Terrestrial Non-insect Arthropods; Mollusks; Terrestrial Worms
Plant Foods: Leaves; Roots and tubers; Seeds, grains, and nuts; Fruit; Flowers
Other Foods: Fungus
Foraging Behavior: Stores or caches food
Source: The Regents of the University of Michigan and its licensors CC License: by-nc-sa
Least chipmunks are adept climbers. Some individuals construct nests high above the ground. Chipmunks climb trees in order to warm themselves in the sun during periods of cool weather (Hamilton and Whitaker, 1979).
Least chipmunks are most active between April and October. Nests are built seasonally, with summer homes being constructed from leaves and bark in rotting logs and tree cavities. Winter nests are located in underground burrows that consist of dried grass, bark, fur, feathers and soft vegetation (Kurta, 1995). With the onset of cold weather, chipmunks retire to these burrows, where they enter torpor and live off stored food until spring (Kurta, 1995). Hibernation in these animals is not as deep as it is in ground squirrels, and they awake frequently to snack on stored food during the winter months (Bergstom, 1999). Least chipmunks are territorial and will defend their nests from invaders.
Least chipmunks are diurnal. In general, they are not social, except for mating and rearing young. However, when provisioned by humans, they are remarkably tollerant of conspecifics (Bergstrom, 1999). (Baker, 1983; Bergstom, 1999; Hamilton and Whitaker, 1979; Kurta, 1995)
Home ranges have been estimated at 1/4 of an acre. Some areas have up to 6 individuals per acre. (Banfield, 1974)
Key Behaviors: arboreal; terricolous; diurnal; motile; sedentary; hibernation; solitary
Source: The Regents of the University of Michigan and its licensors CC License: by-nc-sa
Comments: May be active throughout the day, but prefers the sunny midday hours. Begins semihibernation in late October. Fully active by mid-March. May be active on warm winter days.
Source: NatureServe CC License: by-nc
The mating system of these animals has not been well described. Males emerge from hibernation earlier than females, and apparently engage in some level of competition for mates. It is likely, therefore, that the species is either polygynous or polygynandrous. (Baker, 1983)
Individuals become sexually mature at 10 months of age (Kurta, 1995). Most mating occurs in April when females first emerge from hibernation. Gestation lasts approximately 30 days (Hamilton and Whitaker, 1979). Litter size varies from 2 to 6 young. There is normally a single litter during the breeding season, although females may produce a second litter if their first litter is lost (Burt, 1946). Newborns are naked and pink in color, measuring 50 mm in length and weighing an average of 2.25 g (Banfield, 1974). Eyes open at 28 days and fur is fully grown in by 40 days (Baker, 1983). Lactation lasts approximately 60 days and offspring remain with the mother for six weeks or longer (Kurta, 1995). (Baker, 1983; Banfield, 1974; Burt, 1946; Hamilton and Whitaker, 1979; Kurta, 1995)
Key Reproductive Features: Iteroparous; Seasonal breeding; Gonochoric/gonochoristic/dioecious (sexes separate); Sexual; Fertilization; Viviparous
These chipmunks usually breed once per year.>p
Breeding occurs in early April when these chipmunks awake from hibernation.>p
Parental care in least chipmunks is extensive. Young are altricial, and are not even fully furred until they reach about 40 days of age.
Females chose nursery nests while they are pregnant. These nests are located in stumps, under logs, in brush piles, or rock piles. They are generally connected to chambers filled with cached food supplies. A female positions her nursery nest so that it is protected from rainfall and runoff, to ensure the comfort and health of her offspring when they arrive. Nests are often lines with grass.
Mothers take care of their young until they are weaned, sometime after 60 days of age. They provide food, shelter, grooming, and other care for the pups.
The role of males in the care of offspring is not certain. There are some indications that males may help to defend the home range of female's whose young they have sired. They may even help to maintain the nursery nest, and bring food to the young. (Baker, 1983; Bergstom, 1999; Burt, 1946)
Parental Investment: Altricial; Pre-fertilization; Pre-fertilization :: Provisioning; Pre-fertilization :: Protecting; Pre-fertilization :: Protecting :: Female; Pre-hatching/birth; Pre-hatching/birth :: Provisioning; Pre-hatching/birth :: Provisioning :: Female; Pre-hatching/birth :: Protecting; Pre-hatching/birth :: Protecting :: Male; Pre-hatching/birth :: Protecting :: Female; Pre-weaning/fledging; Pre-weaning/fledging :: Provisioning; Pre-weaning/fledging :: Provisioning :: Female; Pre-weaning/fledging :: Protecting; Pre-weaning/fledging :: Protecting :: Male; Pre-weaning/fledging :: Protecting :: Female; Pre-independence; Pre-independence :: Provisioning; Pre-independence :: Provisioning :: Male; Pre-independence :: Provisioning :: Female; Pre-independence :: Protecting; Pre-independence :: Protecting :: Male; Pre-independence :: Protecting :: Female
Source: The Regents of the University of Michigan and its licensors CC License: by-nc-sa
Least chipmunks are predators of pest insects and may play a role in seed or pollen dispersal.
Source: The Regents of the University of Michigan and its licensors CC License: by-nc-sa
Show/Hide iNaturalist Observations Map for this species. Source: iNaturalist