Like other diurnal sciurids, vision is an important part of commmunication. Visual signals, such as body posture, convey important information to conspecifics.
In addition to visual communication, these animals use a variety of auditory signals to communicate. They use calls to advertize their ownership of a territory, to find mates, and when they feel threatened.
Tactile communication is important between mothers and their offspring, as well as between mates and rivals.
The role of olfactory cues in this species have not been described, but scents are often important in individual recognition. It is likley that there are some chemical cues used by these chipmunks in communication.
Perception Channels: visual ; tactile ; acoustic ; chemical
The primary threat to least chipmunks is habitat loss caused by the encroachment of humans. Hunting or trapping may also pose a small threat. Currently least chipmunk populations are steady.
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
Least chipmunks have no significant negative impacts on humans, though they may occasionally be a nuisance to campers (Hamilton and Whitaker, 1979).
Least chipmunks are predators of pest insects and may play a role in seed or pollen dispersal.
As animals that carry nuts and seeds from one place to another, least chipmunks are probably very important in seed dispersal. They also play and important role as a food source to their predators. They also provide habitat for a number of parasites.
Ecosystem Impact: disperses seeds; creates habitat
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.
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
Primary Diet: herbivore (Granivore )
Least chipmunks, Tamias minimus, are found throughout North America, occupying much of the Rocky Mountain region and the western Great Plains of the United States. In addition, they are found throughout central and western Canada and in parts of Wisconsin, Minnesota and Michigan.
Biogeographic Regions: nearctic (Native )
Least chipmunks are found throughout the boreal and temperate forests of North America. However, least chipmunks prefer more open areas such as forest edges and openings. They are also commonly found near rock cliffs, river bluffs, and open jack pine stands.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: taiga ; forest ; scrub forest
The lifespan of these animals has not been reported. They are reported to have shorter lives than Eastern chipmunks, which can live as long as 11 years.
Status: captivity: 10 (high) years.
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).
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.
Range mass: 42 to 53 g.
Range length: 185 to 222 mm.
Other Physical Features: endothermic ; heterothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: female larger
Average basal metabolic rate: 0.349 W.
Major threats to these animals include weasels, goshawks, Cooper's hawks, snakes, mink, red fox, bobcats, and martens, as well as domestic dogs and cats.
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.
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).
Breeding interval: These chipmunks usually breed once per year.
Breeding season: Breeding occurs in early April when these chipmunks awake from hibernation.
Range number of offspring: 2 to 6.
Average gestation period: 30 days.
Average weaning age: 60 days.
Average time to independence: 60 days.
Average age at sexual or reproductive maturity (female): 10 months.
Average age at sexual or reproductive maturity (male): 10 months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Average birth mass: 2.3 g.
Average gestation period: 30 days.
Average number of offspring: 4.9.
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.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)
It is the smallest species of chipmunk, measuring about 15.7–25 cm (6.2–9.8 in) in total length with a weight of 25–66 g (0.88–2.33 oz). The body is gray to reddish-brown on the sides, and grayish white on the underparts. The back is marked with five dark brown to black stripes separated by four white or cream-colored stripes, all of which run from the nape of the neck to the base of the tail. Two light and two dark stripes mark the face, running from the tip of the nose to the ears. The bushy tail is orange-brown in color, and measures 10–11 cm (3.9–4.3 in) long. In some areas, where range overlap with the yellow-pine chipmunk occurs, it may be difficult or impossible to distinguish the two species in the field; laboratory examination of skeletal structures may be required.
As in other chipmunks, there are four toes on each of the forefeet and five on the hindfeet. Females have eight teats. The brain to body mass ratio for least chipmunks is lower than that for other species of chipmunk living in the same area, suggesting that they prefer less complex environments.
Least chipmunks are found through most of the western United States from northern New Mexico and western North and South Dakota to eastern California, Oregon and Washington, and throughout much of southern and western Canada from Yukon and southeastern British Columbia to central Ontario, and into the Upper Peninsula of Michigan and neighboring parts of Wisconsin and Minnesota. Throughout this range, as many as 21 subspecies have been identified. Less arboreal than other chipmunks, least chipmunks are commonly found in sagebrush habitats and coniferous woodland, and along rivers, but they also occur in alpine meadows, and on the edges of the northern tundra.
Least chipmunks are diurnal and eat seeds, berries, nuts, fruits and insects. They mark areas depleted of suitable food with urine, and do not return to such patches afterwards. Home ranges vary widely, and have been reported to vary from 0.1 ha (0.25 acres) in northern Michigan to as much as 5.5 ha (14 acres) in Colorado. Because of their small size, least chipmunks are generally subordinate to yellow-pine chipmunks, which are able to drive them away from food resources where food is plentiful. However, because they need to eat less food in order to survive, least chipmunks are more numerous where resources are scarce. They are agile animals, and have been recorded running at speeds of up to 7.7 km/h (4.8 mph) in natural conditions.
Least chipmunks spend the winter in burrows and also scatter-hoard food in numerous concealed pits beneath logs and similar cover. Burrows consist of a single chamber about 15 cm (5.9 in) across and tunnels 7.5 cm (3.0 in) in diameter, averaging 1.7 m (5 ft 7 in) in length. They have two to four entrances, often concealed by nearby rocks, and are typically about 18 cm (7.1 in) below the surface. During the summer they may construct temporary nests in trees from leaves and grass, or appropriate hollows made by woodpeckers.
Least chipmunks do not hibernate, or put on excess fat in the fall. Instead, they survive the winter by entering torpor for long stretches of time, waking to eat food cached in the burrow. How much of each winter they spend below ground in this manner depends on the latitude, varying from late November to mid March in Michigan to mid October to late April in northern Manitoba.
Females enter estrus within a week of emerging from their burrow in the spring, and mating typically takes place between March and May. Gestation lasts 28 to 30 days, with a single litter of three to seven young being born each year; females who lose their first litter soon after birth may, however, sometimes be able to breed again in the same year. The young are born hairless and blind, measuring about 5 cm (2.0 in) in length, and weighing 6 g (0.21 oz). They are able to stand and open their eyes at 27 days, and are weaned at 36 days. They are sexually mature at one year, but do not always breed until their second year. They can live for up to six years in captivity.