Chela mechanical function was investigated by comparing individuals of the crayfish Orconectes propinquus (Girard) with and without the mechanical use of their chelae (dactyls held closed with rubberbands or glue) to determine if crayfish need the mechanical function of chelae to feed, to deter predators, to survive in the field, and to copulate with mates. Laboratory studies showed that crayfish did not require the use of their chelae to consume algae or snails, but fewer crayfish consumed juvenile insects when their pincers were non-functional. Male and female crayfish with functional pincers were just as susceptible to snapping turtle predators in the laboratory and just as likely to be recaptured in the field as those with non-functional pincers. Laboratory mating experiments with two males and single female showed that only males with the mechanical use of their chelae copulated. These results indicate that O. propinquus require their chelae for mating but do not require functioning chelae to feed or to survive in the field.