yes they do.
can i ask what setup you are keeping them in? They require brackish water and access to land of atleast 3 times there body size.
thanks
they will come back, but they will not grow back. the legs will appear after the next moult, though depending on the size and severity of the injury, it may take two to fully recover. as endler says, sorry that's 3ndl3r, they need dry land and brackish water. when young they love chicken and pellet food. as they maturer the diet turns to, mostly veg. they also like lots of places to hide.
that said these are LAND crabs, not even close to aquatic. they, given the chance, spend the vast majority of time in the dry. only playing crapping and, sometimes eating in the water. they are also very adept at escape, even the tiniest gap will allow them FREEDOM, this kills more crabs than fish-keepers do, which is saying something.
i have kept them in a community tank, and they did very well. but after the last one escaped i decided, if i get them again, i would keep them in a crab only lodge. this is 75%+ dry land and 30%- water. tank size is kinda a problem, if you want to cycle the tank you will have to go for a tank of 30g 36 inches capacity or more this would sustain 5-10 crabs. in this setup that would give you only 5 gallons of water if the water level is six inches. much less would be hard to keep both clean and cycled, imo. you do however get to see the crab acting naturally, something that you would never witness in a community tank.