Do all hermit crabs have small and big claws?

Diogenidae - The left-handed hermit species are more likely to have equal sized claws but many do have a larger left claw. Having different sized & shaped claws allows hermits more feeding options - for example one claw might be used like a forceps while the other functions as a scoop. read more

The large claw is for defense, but also to cover the opening of the shell. It is also used for holding on to larger foods while the crab eats it with the small claw. It might also be to help balance the crab since most snail shells all spiral the same way. read more