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Amphibians of Washington


Ascaphus truei, Tailed frog

Description. This is a small frog (5 cm total length) that lives in clear, cold mountain streams. It is light to dark brown on the back and usually has slightly granular skin. Adult males are unique among frogs in having a tail-like reproductive organ; females have very small, somewhat tubular cloacal projections.

Distribution (GAP Analysis map) The tailed frog occurs in the Cascade Mountains and Coast Range from southern Canada to northern California, in the Blue Mountains of eastern Washington and Oregon, and in the Rocky Mountains of Northern Idaho and probably western Montana. 

Habitat. These frogs live in clear, cold mountain streams. During rainy seasons, they are occasionally found on land away from streams.

Cool Biology Facts. Tailed frogs are primitive frogs (unlike most other frogs, they have several small ribs) whose closest living relatives live in New Zealand. Tailed frogs are also one of only a few frogs in the world that have internal fertilization, which is accomplished with the tail-like reproductive organ of males; the "tail" is not a real tail like the tail of larvae (tadpoles) and salamanders. Male tailed frogs do not vocalize, presumably because their calls could not be heard by females over the sounds of the rushing streams in which they live. They have very reduced lungs and breathe mostly through their skin.

Conservation status. Tailed frogs live and breed in clear, cold, fast-flowing streams with rock or gravel bottoms. They can be very common in appropriate habitats. However, they are extremely sensitive to stream siltation and warming caused by excessive logging and other human activities. They are most abundant in old-growth forests, but can be common in open streams, such as those around Mt. St. Helens.

Ascaphus truei, Tailed frog (adult male)
Ascaphus truei, Tailed frog (adult male)
Photo by Brad Moon