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Tamias sonomae

Sonoma Chipmunk

Order: Rodentia
Family: Sciuridae

Image of Tamias sonomae
Tamias sonomae - winter coat (upper right) and summer coloration (lower left)
Click to enlarge. (54 kb)

Conservation Status: Least Concern.

Young male Sonoma chipmunks disperse from the nest after weaning, but females remain near where they were born. From December through June, males travel extensively, seeking mates and competing with other males. Because of this, they are more exposed to predators than females. About equal numbers of male and female young emerge from the nest, but more females than males survive their first winter. Apparently a number of females do not survive their first attempt at reproduction, however, because by fall the number of yearling males and females in a population is about equal. On average, females live longer: by the time they are 3-5 years old there are more females than males. These chipmunks commonly occur in low, dry forests of ponderosa pine, and in chaparral and open areas of redwood forests.

Sexual Dimorphism:

Average: 245 mm
Range: 220-264 mm

Range: 63-77 g


Grinnell, J., 1915.  Eutamias sonomae, a new chipmunk from the inner northern coast belt of California, p. 321.  University of California Publications in Zoology, 12:321-325.


Mammal Species of the World

Mammalian Species, American Society of Mammalogists' species account

Distribution of Tamias sonomae