There are several species of Crayfish in New York State.  There are those that prefer small protected streams, others that like large rivers, others that are specific to lakes and ponds, and there are marine and brackish species as well.  Crayfish are a lobster-like crustacean, they breathe water with internal gills, and for the most part are nocturnal.  The two foremost legs are adapted into large pincers that they use for battles over territory and for defense.  The legs, including the pincers, will regenerate if removed, but a crayfish without pincers has less of a chance for survival.  Females of this group carry the eggs underneath the tail until they hatch.  The young then disperse on their own.