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Amphibians of Washington

Dicamptodon tenebrosus, Coast giant salamander

Description. This is one of the largest terrestrial salamanders (up to 35 cm total length) that lives in clear, cold mountain streams and adjacent mountain forests. Larvae and adults in the aquatic form are brown, have short gills, and usually have few, if any, fields of glandular spots on the body. Terrestrial adults are usually marbled all over with brown and black.

Distribution (GAP Analysis map) The coast giant salamander occurs in the Cascade Mountains of Washington and Oregon, the Willapa Hills of southwestern Washington, and the coast ranges of Oregon and California ; it is absent from the Olympic Mountains. It occurs with Cope's giant salamander in the Cascades of southern Washington and northern Oregon, and in southwestern Washigton and northwestern Oregon.

Habitat. These salamanders live in clear, cold mountain streams and adjacent forests. They spend most days underground or under rocks in the streams, but in the evenings move about openly on the streambottom and on land during rainy weather.

Cool Biology Facts. The coast giant salamanders usually metamorphose into terrestrial adultsm, but sometimes mature and reproduce in the aquatic form. Maturing in the aquatic form is called paedomorphosis (or sometimes neoteny). In Cope's giant salamanders, this happens because most individuals lack the physiological ability to respond to the hormones that induce metamorphosis in other salamanders. However, it is still unclear why this sometimes happens in coast giant salamanders (and many ambystomatid salamanders such as northwestern salamanders).

Conservation status. These salamanders breed in clear, cold, fast-flowing streams with rock or gravel bottoms. They can be very common in appropriate stream and forest habitats, although both aquatic and terrestrial adults are usually difficult to find. However, they are sensitive to stream siltation and warming caused by excessive logging and other human activities.

Dicamptodon tenebrosus, Coast giant salamander
Dicamptodon tenebrosus, Coast giant salamander
Photo by Brad Moon