KELP FOREST HOME
This crafty crab fastens pieces of seaweed, algae, sponges and other creatures to its back. These "decorations" take hold and grow and soon the crab is perfectly hidden in its rocky home.
Why don't seaweeds and sponges just fall right off a decorator crab's back? The crab has special hooked hairs on its shell called hooked setae. Like Velcro, these hairs attach and hold on.
As a crab's old shell loosens, a new one starts to grow under it until finally the old shell splits apart, and the animal crawls out wearing a new soft shell. Soon its soft shell will harden, but before it does, the crab absorbs water and grows larger.
A decorator crab
grows as it gets older, but its shell doesn't, so once in a while the crab has to shed its old shell and grow a new one. Then it's time to redecorate! Expert recyclers, they remove the anemones, sponges and other decorations from their old shell and reuse them to decorate their new shell.