In desert regions, they occur along the Mojave and Colorado rivers and in areas where irrigation creates suitable habitat. Adults are opportunistic feeders taking both aquatic and terrestrial prey items. Tadpoles use shallow waters near shore for at least six months while completing development. Permanent water is often required for the completion of larval development.
Adults often travel considerable distances from water on rainy nights.
Dispersal of juveniles away from breeding sites may occur without rain. This species occurs near permanent or semi-permanent water in a variety of California habitats. It is absent from high mountain and arid deserts. Terrestrial individuals may be active at all times of the day. In areas with mild winters, bullfrogs are active all year, but they undergo periods of inactivity or hibernate in cold climates.