Hermit crabs claw fell off

Question
my little sisters (land) hermit crabs big claw has fallen off.
will it grow back and keep on living?
Also any ideas why i would of fallen off?
Thanx Sarah

Answer
Hello, Are you sure its not just moulted exoskelaton? the crabs moult there old skin from time to time as they grow. If this isnt the case and your sure he doesnt have a smaller claw still attached(the crab appers smallers after amoult until the new skin hardens again) I assume he was in a fight with another crab in his habtat or when he was brought home and the claw was injured and died off and fell off.