 
Camouflage: the art of blending in
Camouflage is a popular defensive strategy in the ocean. Instead of risking life and limb defending oneself from predators, it’s much easier and safer to simply blend in and avoid altercations all together. But camouflage can also be a popular attack strategy. Sneaking up on dinner is much less complicated if the entrée has no idea it’s about to be devoured.
The art of blending in is used by many different ocean animals in many different ways. Here are some great camouflage tricks used by a few ocean masters of disguise:
Spot prawns begin their lives as small red larvae and grow to become red adults, but during their juvenile stage of life they are green. After spending six weeks as reddish larvae, spot prawns settle in coastal areas in eel grass beds and start the process of growing up. But red really stands out in a field of green, so to blend in with their environment and stay well protected during their vulnerable juvenile stage, spot prawns change to a shade of light green. Once they reach adulthood, spot prawns leave eel grass for deeper water and return to being red. Spot prawns are the largest species of shrimp on the west coast of North America and reach up to 10 inches in length. (Stop by and visit our juvenile spot prawns in the Aquatic Nursery.)
Speckled sanddabs are a type of flatfish that uses color changing cells called chromatophores to blend into sand or rock covered ocean floors. If a speckled sanddab is lying on sand, the chromatophores gradually change to a pale tan color. If a speckled sanddab is lying on darker colored pebbles, then the chromotophores gradually change to a marbled brown. Sanddabs use this color changing ability to hide from predators and to ambush prey. (To see the color changing powers of sanddabs, visit the Kelp Forest Room in our Exhibit Hall.)
Masking crabs (also called moss crabs) decorate their shells with algae, sponges, bryozoans, anemones and whatever other bits of material might be lying around to match their surroundings. Their shells have tiny hooked bristles called setae that hold decorations on like micro-Velcro pipe cleaners. When masking crabs molt, they have to redo all the decorations for the new exoskeleton, sometimes reusing choice decorating pieces from the old one. Once male masking crabs reach sexual maturity, they don’t bother decorating any more, probably because they are large enough to intimidate predators and no longer need camouflage. (Look for masking crabs in tank number 9 and 14 in the Exhibit Hall.)
Post Date: Friday, December 7, 2012
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