Procambarus clarkii
Shore crabs quickly (within 1 or 2 trials) learn to avoid one of two dark shelters if choosing that shelter consistently results in them receiving an electric shock. The crayfish "Procambarus clarkii" and the crab "Chasmagnathus granulatus" learn to associate an electric shock with a light turning on, or with the occupancy of the light compartment of the aquarium, respectively. They quickly learn to respond to these associations by walking to a safe area in which the shock is not delivered (crayfish) or by refraining from entering the light compartment (crab).