WhyReef - Lifestyle
Like lobsters and shrimps, the red spotted coral crab is a crustacean, which means it has a hard shell, or exoskeleton, that protects it from predators. When it grows larger, it will molt, or get rid of, its old exoskeleton. It will then grow a larger exoskeleton to fit its new size.
Alastair Fothergill, (2001). Blue Planet [DVD], BBC-Discovery.