Wednesday, July 19, 2017


Camo Crab

I decorate myself so as to be noticed: “Cool shoes!” “Nice earrings!”  Decorator crabs do just the opposite.  Their goal is to blend in, to be unnoticed.

Sea otters love crabs for lunch.  (Actually one decorator crab is more like otter popcorn, since otters have to eat 15-20 lbs of food every day.  But tasty popcorn.)  We call them “decorator” crabs because of their talent at carefully attaching little bits of seaweed or sponge or anemone (or whatever they can find in their environment) to their back.  “Hey man, I’m just some seaweed, you don’t want to eat me.”  Unlike their cousins the pinching crabs, these fashionistas will not hurt you; hence they are popular in touch pools.

It’s fun to watch them find a piece of kelp, chew it a bit to make it rougher, and then affix it to their back, which has tiny hooked stiff bristles called setae that are like Velcro.  They work deliberately (one British scientist called them, admiringly, “industrious”) and are thrifty – when they have to shed their too small shell and grow a new exoskeleton, they will take a particularly fine piece of sponge and transfer it to their new shell, like moving a favorite pin to a new jacket. 

Describing to guests at the Aquarium why crabs do this, I say they are being good Californians, they are conserving energy.  If your method of survival is to run away, or fight, you have to consume more energy.  But if you lay low and blend in, you don’t need as much fuel.   Another life lesson we could learn from our crustacean cousins. 

We used to have a decorator crab exhibit that put them in with different colored yarn to make the point that they use whatever they can find near them for decoration.  We would change the yarn with the season (eg blue and white for Hanukkah, red and gold for the 49ers).  I think the Aquarium came to feel it was not scientific enough, but I thought it was sort of cute.

But cute is not really the point here.  It’s life and death.  “Decorator” is actually a misnomer, it’s not about looking good or even attracting a mate.  It’s surviving until tomorrow.  “Camouflage” is a better metaphor.  Sometimes I say it’s like a soldier putting plants in her helmet.  Kids actually get that image more readily than “decorating.”  

Despite all kinds of cute articles about “high fashion at low tide” and “best dressed animal in the sea,” it’s an otter-eat-crab ocean out there and crabs don’t want to be on either the menu or the runway.  Let’s call them camo-crabs.

Crab?  What crab?  All I see are, yes, beautiful sponges and anemones.  Hoping to live one more day.

Job 12:7 “But ask the animals what they think—let them teach you;
    let the birds tell you what’s going on.
Put your ear to the earth—learn the basics.
    Listen—the fish in the ocean will tell you their stories.”
Come for a service trip or pilgrimage to our Blue Theology Mission Station in Pacific Grove and many cute decorator crabs will tell you their story.

Photo by NOAA’s fabulous Steve Lonhart:

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