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Range DescriptionThe species' range extends from central British Columbia, central Alberta, and southwestern Manitoba in Canada, south through all of the western United States (east to western South Dakota, western Nebraska, Colorado, extreme western Oklahoma, and New Mexico) to (disjunctly) northern Baja California. There are many isolated populations around the margins of the main range (Fitch 1983, Rossman et al. 1996, Grismer 2002, Stebbins 2003), notably in the Sierra Nevada and San Bernardino Mountains of California, and Sierra San Pedro Martir in Baja California (subspecies T. c. hueyi). Its elevational range extends from sea level to 3,995 m asl (13,100 feet) (very rarely); usually below 3,355 m asl (11,000 feet) (Hammerson 1999, Stebbins 2003).