arthropods
A crab is an arthropod.
Yes
Actually, you can't make your crabs have babies in captivity, they can only reproduce in the wild because they lay their eggs in the ocean.
Because since they are kind of hermits for living and often hiding in their shells, they are called hermit crabs. But, they aren't anything else like hermits besides that.
Go to http://en.wikipedia.org/. Search for hermit crab. The answer you seek is in the second sentence.Hermit crabs are not true crabs.