Signal Crayfish (Pacifastacus leniusculus)

The signal crayfish is native to North American west of Rocky Mountain, habituating on rocky substrate rivers, streams or lakes. They are bluish-brown to reddishbrown in color with robust, large, smooth claws and can grow up to 6 inches long. They have a white to pale blue-green patch near the claw, like the white flags that signalmen used for directing trains—hence the name.