Of the 25 chipmunk species, all but one can be found in North America. They range in size from the least chipmunk -- the smallest species at about 7 inches long -- to the eastern chipmunk, which grows up to 11 inches long. They live in a variety of habitats, from scrub deserts to forests, where they scamper through the undergrowth foraging for the nuts and berries that make up the bulk of their diet. Despite being mostly solitary creatures, they have many methods of communication.
Chips and Chucks
Chipmunks' vocal communication, exemplified by eastern chipmunks, consists primarily of repeated series of chips and chucks, which can last for up to half an hour at a clip. Most chipmunks defend the area at least a few square feet around their burrows, and chips and chucks often serve to advertise their territorial claim. These territorial calls sometimes lead to aggression if some other chipmunk steps forward to challenge the claim. These vocalizations can be quite complex. The yellow-pine chipmunk, for example, has as many as 10 distinct recognizable calls, each of which communicates different information to other chipmunks within hearing distance.
Trills are briefer vocalizations than chips or chucks, reserved for desperate alarm calls by a chipmunk being actively pursued by a predator. Other chipmunks react to these calls by exhibiting increased vigilance if they're aground or staying in their burrow until the coast is clear. Although sounding the alarm can put the chipmunk at greater risk by disclosing his location to other predators, the creatures seem to believe the potential cost is outweighed by the greater benefit of warning family members. Chipmunks tend to trill more often when traveling through territory they know is near relatives' burrows.
Chipmunks also communicate using body language when they encounter other chipmunks. Flattened ears, fluffed tails and jerky movements offer some visual clue as to the animals' more aggressive intentions. Like other animals, they chase each other and demonstrate basic mammalian postures to indicate aggression or dominance and submission. In nonaggressive encounters, such as mating, chipmunks touch noses and sniff each others' cheeks and necks. They also sniff each others' rears, obtaining chemical information through secretions from anal glands.
According to studies published in the "Journal of Mammology," chipmunks understand and heed alarm calls from woodchucks. While both woodchucks and chipmunks are rodents, they are only distantly related and are classified in different genera. In North America, woodchucks and chipmunks share habitat and a few common predators, including hawks, eagles and foxes. Chipmunks have learned the meaning of woodchucks' alarm calls and react virtually the same way as they would to the alarm of a fellow chipmunk. Woodchucks seem to understand chipmunks' alarm calls as well, although they aren't quite as responsive to them -- most likely because woodchucks are larger and less vulnerable than chipmunks.
- National Geographic: Chipmunks
- State University of New York College of Environmental Science and Forestry: Adirondack Ecological Center: Eastern Chipmunk
- University of Michigan Museum of Zoology: Animal Diversity Web: Tamias Striatus
- Wired Science: Chipmunks and Woodchucks Eavesdrop on Each Other
- University of Michigan Museum of Zoology: Animal Diversity Web: Tamias Amoenus
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