Chipmunks are small rodents of the squirrel family with a total of 25 different species (see bottom of page), all part of the scientific family, in the family Sciuridae. There are three genera in this family: Tamias (eastern North America), Neotamias (western North America) and Eutamias (Eurasia).
Chipmunks are lively little creatures that are found mostly in North and West America with one species (Asia’s Tamias sibiricus) native to Eurasia. Chipmunks are kept as popular and entertaining pets.
Chipmunks vary in size and color depending on species. Their size ranges from 7 – 8 inches in length and 32 – 50 grams in weight in the smallest chipmunks to 11 inches in length and 125 grams in weight in larger chipmunks.
Chipmunks coats range from reddish brown to grey in color with contrasting dark or light stripes on the side of their faces and across their backs and tails. They have white fur on their underparts and their tail is brown, with varied shades of black near the tip. Chipmunks have large, glossy eyes and characteristic bushy tails measuring 2 – 5 inches which have made them a favourite character with animators.
Chipmunks have small but prominent ears which face forwards, small eyes set on the sides of their heads and a pointed muzzle. Although a chipmunks mouth is small, their cheek pouches can expand up to 3 times the size of their head. The chipmunk digs with its front paws, which have four sharp claws on each. The dirt is pushed to the surface, and then carried away in the animals cheeks.
Chipmunks are generally seen scampering through the undergrowth of a variety of environments from scrublands, alpine forests to shrubby deserts. Chipmunks construct complex burrows which can measure 3 – 4 metres in length. These burrows have several entrances, tunnels and chambers for sleeping which are kept very clean. Shells and faeces are stored in refuse tunnels. sleeping areas are enlarged and filled with shredded leaves to make a comfortable bed. Food is normally stored in the lowest tunnels, to keep it cool and fresh. Some species of chipmunk make their homes in logs, bushes are abandoned nests.
Chipmunks have a varied omnivorous diet mainly consisting of nuts, fruits, seeds, berries, grains, birds eggs, small frogs, fungi, insects and worms. Food is stuffed into their large cheek pouches and carried back to store in their dens. Lots of food is gathered and placed in their burrows at the beginning of autumn to store for the winter.
Some species of chipmunk make many caches of food. These two behaviours are referred to as ‘larder hoarding’ and ‘scatter hoarding’. Larder hoarders usually remain in their nests until spring. Chipmunks generally gather food on the ground in areas with underbrush, rocks and logs, where they can hide from predators like hawks, foxes, coyotes, weasels, and snakes. They will climb trees to collect acorns and hazel nuts, however, they are not as agile as their cousins, the squirrel.
Chipmunks fulfil several important functions in forest ecosystems. Their activities which include harvesting and hoarding tree seeds play a crucial role in seedling establishment. Chipmunks also play an important role as prey for various predatory mammals and birds, however, they are also opportunistic predators themselves, particularly with regards to bird eggs and nestlings.
Chipmunks that reside in urban areas have been known to take handouts from humans, however, human food is not stored, it is just enjoyed as a novelty.
Chipmunks are very lively and very fast. They have a bird-like chip which is used when danger is sensed or as a mating call for female chipmunks. Other communications include gestures such as waving their tails enabling them to communicate effectively with others of their species. Chipmunks are solitary animals and male and female do not pair until breeding season. Although chipmunks hibernate from late autumn until early spring, they do not store fat, instead they slowly gnaw away at their supplies throughout the winter, waking every 2 weeks or so to eat.
Chipmunk breeding season occurs in early spring and then again in early summer. Litters of 4 – 5 young are produced after a gestation period of 30 days. Western chipmunks only breed once a year. Young are born in burrows where they remain for about 6 weeks. Within 2 weeks of emerging from their burrows they become independent and begin to gather their own stores of food for the winter ahead. Chipmunks are social animals, and both the male and female raise their young. Chipmunks have a life span of 2 – 7 years in the wild.
Chipmunk Conservation Status
Although chipmunks are vulnerable to forest fragmentation, they are not currently threatened. However, the Palmers chipmunk (Tamias palmeri) is considered a vulnerable species.
Allens Chipmunk Tamias senex Alpine Chipmunk Tamias alpinus Bullers Chipmunk Tamias bulleri California Chipmunk Tamias obscurus Cliff Chipmunk Tamias dorsalis Colorado Chipmunk Tamias quadrivittatus Durango Chipmunk Tamias durangae Eastern Chipmunk Tamias striatus Grey-collared Chipmunk Tamias cinereicollis Grey-footed Chipmunk Tamias canipes Hopi Chipmunk Tamias rufus Least Chipmunk Tamias minimus Lodgepole Chipmunk Tamias speciosus Long-eared Chipmunk Tamias quadrimaculatus Merriams Chipmunk Tamias merriami Palmers Chipmunk Tamias palmeri Panamint Chipmunk Tamias panamintinus Red-tailed Chipmunk Tamias ruficaudus Siberian Chipmunk Tamias sibiricus Siskiyou Chipmunk Tamias siskiyou Sonoma Chipmunk Tamias sonomae Townsends Chipmunk Tamias townsendii Uinta Chipmunk Tamias umbrinus Yellow-cheeked Chipmunk Tamias ochrogenys Yellow-pine Chipmunk Tamias amoenus