Today the educators received a very pleasant surprise while cleaning the aquarium. One of our baby horseshoe crabs molted.
The yellow shell in the picture is the molt (old shell) that the baby horseshoe crab grew out of overnight. Horseshoe crabs must molt to grow because their exoskeleton only allows their body to expand so much in their shell. Horseshoe crabs go through 16 or 17 molts during development.
The new horseshoe crab, which is about 1/3 larger will have a soft shell initially until the completely hardens. During that time the baby horseshoe crab will stay protected in the sand.