Pacifastacus leniusculus

"Crawdads — members of the superfamilies Astacoidea and Parastacoidea — are freshwater crustaceans resembling small lobsters, to which they are related. They breathe through feather-like gills and are mostly found in brooks and streams where there is fresh water running, and which have shelter against predators.

The signal crayfish, Pacifastacus leniusculus, is an American crayfish indigenous to the western United States.^[1] Members of this species are up to 15 cm in length.^[2] They are bluish-brown to reddish-brown in color with robust large smooth claws. They have a white to pale blue-green patch near the claw hinge.^[2]

Like all crayfish, they are solitary animals and are omnivorous, although their diet is mainly vegetarian they will eat anything from decaying roots and leaves to meat, including crayfish smaller than themselves."
From Wikipedia: http://en.wikipedia.org/wiki/Signal_crayfish