For those of you who are old enough to remember the cartoon, Alvin and the Chipmunks, they were a trio of brothers who got into all sorts of mischief; the cartoon characters were not too far off from the real thing. Chipmunks are known for eating flower bulbs, getting into bird feeders, and making holes all over your yard, these little fellows can be real rascals.
The eastern chipmunk (Tamias striatus), is the smallest member of the squirrel family and the order Rodentia, or rodent. It is believed that the word “chipmunk” is derived from the word chetamnon, the name given to it by the Chippewa Indians. Eastern chipmunks are found in the United States east of the Great Plains, north to Maine, and south to parts of Florida. There are 25 species of chipmunks in the world; North America is home to 24 chipmunk species. Only the Siberian chipmunk lives outside North America. Of the 24 North American species, 23 live west of the Great Plains. Researchers are still puzzled as to why there is only one species in the East. The biggest species of chipmunk is the Eastern Chipmunk. Chipmunks have short, dense fur that has a reddish appearance on top. There are five black stripes on the back, one down the center, and two on each flank outlining a white stripe. There is a white eyeline above and below each eye, separated by a slash of black. It grows to 11 inches and weighs up to 4.4 ounces. Their tails can grow as long as 3 to 5 inches.
Eastern chipmunks usually mate twice a year, once in the early spring from March to early April and again from early June to mid-July. The female rebuffs the male after mating and he does not share in the rearing of the young. A litter of 2-5 tiny, 2.5 inch, hairless, and blind young are born after a 31 day gestation period. The first litter is generally born in April and May, and the second in July and August. At 6 weeks, under their mother’s watchful eye, they begin to take short trips out of the burrow. At week 7 or 8, the mother becomes more aggressive toward her offspring to prepare them for their independence. Two weeks later, the mother denies them access to the burrow; the young are forced to disperse and find or dig their own home. When the young disperse in the spring and fall, adults occupying nearby burrows give loud “chip-chip-chip” calls outside the burrow entrance, presumably to notify the young of occupied territory. Humm.. I wonder if that works for humans. Probably not!
Chipmunks prefer forested areas and can climb trees, shrubs, and…birdfeeders. Chipmunks are omnivores and they aren’t picky about what they eat. They consume various types of seeds as well as fungus, helping to spread the mycorrhizal fungi that live around tree roots and are critical to tree survival. They also eat fruit, nuts, insects, worms, bird eggs and even nestling birds and baby mice. They probably don’t actively hunt for eggs and hatchlings; just eat them when they find them. They are most active at dusk and dawn. Chipmunks spend most of their days foraging. Chipmunks help disperse the seeds of trees and other plants. A single chipmunk can gather up to 165 acorns in a day.
Chipmunks make homes for themselves by creating burrows that consist of an underground tunnel system or by making nests in logs or bushes. Their tunnel systems can be 10 to 30 feet long. Though you may see chipmunks around each other, they are not social animals. They like to keep to themselves and only interact during mating season. During the warm months, chipmunks will stuff extra food into their cheek pouches. These cheeks are massive grocery bags. They can stretch to be three times larger than the chipmunk’s head. When they have a full load, they carry the food to their home and store it.
One of the true hibernators, chipmunks hibernates throughout the winter. But they don’t sleep all the way through the season. They retreat to their burrows and awake every few days, raise their body temperatures to normal, feed on stored food rather than fat reserves, and urinate and defecate; then depending on the weather go back to sleep or leave the burrow to investigate. When chipmunks are in the deep sleep phase of hibernation, they may be very difficult to arouse. Their heart rate declines from about 350 beats per minute to perhaps 4. Body temperature may drop from 94 degrees F to whatever the temperature of the burrow—as cold as 40 degrees F.