Decorator crab

Natural history

As long as the crab stays in the neighborhood, it blends in and looks at home. Large decorator crabs don’t decorate as much as smaller crabs. But plants and animals may still settle, take hold, and grow on the decorator crab’s shell without help.

Conservation

Oil spills and the runoff of pesticides, used oil, paint solvents, and other chemicals endanger the decorator crab's coastal habitat. As stewards of the ocean, we must carefully dispose of hazardous materials like these or, better yet, use environmentally-safe products.

Cool facts

• The decorator crab is an important food source for some fishes, including croakers and cabezon.
• A crab’s shell doesn’t grow, but the crab does. To solve this dilemma it must molt as it grows, shedding its old exoskeleton and forming a larger one. The old shell loosens as a new one forms beneath it. When the old shell splits, the soft-bodied animal crawls out. Before its new shell hardens, the crab absorbs water and expands to a size larger than before the molt. While the new shell is hardening, the crab hides from predators. Once they’ve reached sexual maturity, decorator crabs stop molting.
• The decorator crab recycles its living decorations during the molting process. It removes the anemones, sponges and other decorations from its old shell and uses them to adorn its new shell.