Covered in little hooks for which to attach camouflaging doodads, these decorator crabs are the prima donnas of the tide pools.
There are all kinds of wonderful tactics in Mother Nature's bag of camouflage tricks, from caterpillars assuming the appearance of snakes to octopus's shapeshifting split-second transformations. But really, it's possible that none are as charming as the talents of the decorator crab.
With 700 species of these marvelous crabs across the planet, California is lucky to call a dozen or so their own. Dwelling in tide pools and kelp forests, the crabs have one tragic flaw. They're delicious. But on the lucky flip side, they've learned the careful art of camouflage by way of attaching bits of finery to specialized Velcro-like hooks on their bodies.
Some just accessorize their heads, others go tip-to-claw – but regardless of elegant or all-out kooky, they do it with a precision that is truly remarkable.
“It’s not a glue or anything; they have these hooked hairs all over their shells,” said biologist Jay Stachowicz, who studies decorator crabs at the University of California, Davis. “Through microscope photography we can see that it looks just like Velcro, except probably even better, even more hooked.”
Thick and curled and arranged in rows, the frippery-ready hooks are the perfect spot to attach bits of seaweed or kelp or whatever else they might find. Bringing the bit to the hook, the crab nestles it in until it's firmly in place.
“For smaller crabs in particular, it’s important that the algae be small enough to fit within the rows of hooked hairs,” said Stachowicz. “So very small, slender seaweed or sheet-like seaweeds are often chosen because they attach well.”
Some of the more extreme decorators, however, take it a step further with the addition of live anemones. Now what a hat that would make, rather Victorian, in fact. Not only does the anemone help to hide the host, but it also becomes an ersatz weapon. How's that for snazzy, a fancy hat that stings aggressive strangers? According to KQED, for whom we can thank for the incredible Deep Look video below, over time, the anemones and seaweed can spread across the crab’s shell, fed by nutrients from the crab itself. It can get quite heavy, but nobody ever said being fancifully fashionable was easy ... but thankfully for decorator crabs, looking good is good for survival.
See the fab crabs in action below.