EPOW - Ecology Picture of the Week

Explanation:   Enjoying the cool clear waters of Graham Gulch -- a tributary to Freshwater Creek in coastal Humboldt County, northwestern California -- is this Pacific Giant Salamander. 

Note the feathery gills -- smaller than those found on larval Northwestern Salamanders.  The gills also signify that this specimen is neotenic, meaning that it has not yet metamorphosed into the terrestrial, adult form that lacks gills. Pacific Giant Salamanders can reach 30 cm (about 12 inches) in either neotenic or metamorphosed forms.  

In the neotenic form, Pacific Giant Salamanders usually are a dull brown or gray.  In the adult form, shown below, they become more mottled.  Both patterns likely serve as cryptic or camouflage coloration to help hide the animal.  In fact, the species name "tenebrosus" is Latin for "dark" or "gloomy," (as in "tenebrous") but this might also refer to the dark corners under logs and rocks in which they hide.  

Mottled skin pattern of metamorphosed 
adult Pacific Giant Salamander

These neotenes seem sluggish but are deceptively quick and can be very difficult to catch by hand.  

Pacific Giant Salamanders are one of 4 giant salamanders found in the coastal and inland region of the western U.S.  This species is found from British Columbia Canada down through northwestern California.