At other sites, esp. around the TX City Dike, we found roseate spoon bills. The teachers are looking at a blue crab that has recently molted its outer skeleton, or exoskeleton. Crabs and lobsters are members of a group of invertebrates that shed their exoskeleton in order to grow. After they have molted, it takes a few days for the new exoskeleton to harden. Until it does harden, the crab can be food for other crabs.
Hermit crabs gather in large numbers to exchange their old shells for new ones.
Unlike most crabs, they have a soft belly that they protect by using the shell of a dead snail. Most notably, sea anemonies. These relatives of the coral adhere to rock and use thier sticky tentacles to trap food. Sargassum is a type of floating algae that is found in the middle of the Atlantic Ocean. This area is appropriately named the Sargasso Sea.