Ever wonder why you find so many dead crabs on the beach during the summer? Most of these “dead crabs” are actually crab molts. A molt is an exact copy of a crab, complete with gill coverings, without the actual animal in it! In order to grow, crabs have to shed their hard outer shell, also known as their exoskeleton. When a crab is ready to molt, it backs out of its shell through a split at the back edge of its carapace (the large flat surface on its back). This molting reveals the crab’s new soft shell, which fills with water to make the shell bigger than the old one. During the week it takes for the new shell to harden, the crab hides and doesn't eat. The crab then spends the next year growing to fill the shell.
Dungeness crab molt