Identification and Distribution of Spiny Pocket Mice (Chaetodipus) in Cismontane Southern California
The San Diego Pocket Mouse (Chaetodipus fallax) and California Pocket Mouse (C. californicus) frequently are confused with each other. The shorter, more rounded ears of San Diego Pocket Mice, and to a lesser extent their smaller hind feet, are the best external means of distinguishing them from Cali- fornia Pocket Mice. The two species are largely allopatric, californicus to the north and fallax to the south, but their ranges overlap somewhat in cismontane southern California. California Pocket Mice occupy higher elevations in this area and farther south, whereas San Diego Pocket Mice are generally found at lower elevations and extend no farther north than southeastern Los Angeles County.
Erickson, Richard A. and Patten, Michael A.
"Identification and Distribution of Spiny Pocket Mice (Chaetodipus) in Cismontane Southern California,"
Bulletin of the Southern California Academy of Sciences:
Available at: https://scholar.oxy.edu/scas/vol98/iss2/3