During the spring and summer activity period, adults are always found in the immediate vicinity of deep pools along stream courses. Populations are also known from a few desert palm oases. During spring and summer, individuals may be active at all hours, but concentrate most activity between late afternoon and midnight. They are inactive from late fall through winter. Frogs are essentially inactive in their winter hibernacula.
Males apparently defend small territories by vocalization or physical combat.
Breeding and egg-laying occur during a brief period from March to May depending on local conditions. Tadpoles and adults may compete for space and food with Pacific treefrogs in places where the two species coexist. Various life stages are probably eaten by garter snakes, especially Thamnophis couchi. Observations on the ecology of the canyon treefrog, Hyla californiae. Gaudin, A. J. 1979.