The holiday season is upon us, signaling the time for festive holiday décor. Twinkling lights line the streets and ribbons, garlands and ornaments add an extra dash of cheer to the air. If you’re feeling like your holiday décor is in a rut, try taking some tips from a decorating pro.
The fine hairs covering the shells of decorator crabs are hooked like Velcro, allowing them to cover themselves with some very unique accessories. Photo courtesy of Aquarium of the Bay
By Mallory Johnson
Published: December, 2013
The holiday season is upon us, signaling the time for festive holiday décor. Twinkling lights line the streets and ribbons, garlands and ornaments add an extra dash of cheer to the air. If you’re feeling like your holiday décor is in a rut, try taking some tips from a decorating pro.
If you’ve ever been diving or visited an aquarium and seen something resembling a walking plant, look closer—there just might be a crab under there. Decorator crabs are also known as masking crabs or moss crabs, but the latter name best describes them. The backs of their shells are covered in short hairs, called setae, giving these crabs the appearance of being covered in moss.
But the crabs don’t just leave the moss alone. The setae along the shells are functional and are actually hooked, giving the covering a Velcro-like quality. Decorator crabs use the setae to cover themselves with some very unique accessories.
These crafty crustaceans adorn their shells with various items from their surroundings, including seaweed, anemones, sponges and bryozoans by hooking them to their setae. This gives these crabs a unique form of camouflage, allowing them to blend in to various parts of their environment to avoid pesky predators. Another advantage to these decorations is that they can double as a meal. Decorator crabs tend to feast on algae, sponges and bryozoans—the same items they embellish themselves with, meaning they don’t necessarily have to go far to find their next meal.
There’s another smart lesson we can learn from decorator crabs when it comes to holiday ornaments. These clever crustaceans are not only keen decorators, they’re resourceful as well. During the molting process, these crabs will shed their old exoskeleton to make way for a new, larger one. Once they have replaced their shells, they need to redecorate to continue to hide from predators. Instead of starting from scratch, however, they take the anemones and other items off of the old shell and recycle their thrifty decorations, reusing them on the new shell.
Decorator crabs generally only accessorize their shells during their juvenile stages, while they are still small and more vulnerable to predators. As they mature, they are less threatened by other species and therefore no longer feel the need to get dressed up to go out. This doesn’t always stop others from taking on the job for them, though. With their hooked setae being so effective, other plants and animals simply get stuck on their shells.
You can learn more about decorator crabs when you visit Aquarium of the Bay, and see if you can spot these cleverly disguised crustaceans in our tanks.
Mallory Johnson is the Public Relations Coordinator for Aquarium of the Bay, a nonprofit organization dedicated to protecting, restoring and inspiring the conservation of San Francisco Bay and its watershed.
