The most common amphibians in the park are the canyon treefrog (Hyla arenicolor), red-spotted toad (Anaxyrus punctatus), and Woodhouse's Rocky Mountain toad (Anaxyrus woodhousii). These are all riparian (streamside) species which rely on the Colorado River and its perennial tributaries in the park for breeding, since their egg-masses and tadpoles are water-bound. Although these common species require water sources, they are far more tolerant of desiccation than most other amphibians. Red-spotted toads have been found as far as one-half mile from the nearest known water source.
Northern leopard frogs (Rana [Lithobates] pipiens), which are also riparian species, are native but very rare to the Colorado River corridor. Efforts to reintroduce this species, which experienced population declines following the building of Glen Canyon Dam, are currently underway.