Comments: Eats mainly small mammals; also birds, lizards, and rarely amphibians (see Ernst 1992). See Diller and Johnson (1988) for predation rate on small mammals in southwestern Idaho. In British Columbia, gravid females generally did not feed (Macartney and Gregory 1988, Macartney 1989); feeding by gravid females has been observed in some areas (e.g., Idaho, Wallace and Diller, 1990, J. Herpetol. 24:246-253). Juveniles in some regions prey mostly on lizards rather than on small mammals.