Eggs hatch in 18 to 30 days and the tadpoles grow and develop for 13 to 16 weeks prior to metamorphosis in mid-summer. Oregon spotted frogs mature and begin breeding at two or three years of age. Among the most significant of predators are various introduced species. Because of their life histories and habitat affinities, these introduced species pose serious threats to Oregon spotted frog populations. Oregon spotted frogs are almost entirely aquatic in habit, leaving the wetlands only occasionally and for short duration.
Wetlands associated with lakes, ponds, and slow-moving streams can provide suitable habitat.
However, these aquatic environments must include a shallow emergent wetland component to be capable of supporting an Oregon spotted frog population. Historically, this critical element was found in the floodplains of many larger water bodies. Adult female and juvenile frogs, in particular, spend summers in relatively warm water of this shallow emergent wetland environment. Historically, the shallow floodplain pools that Oregon spotted frogs inhabited were drained, diked and filled to accommodate human needs. In the Puget Sound lowlands, existing wetlands represent a small proportion of what was present in pre-settlement times.