COLUMBUS CRABS

      The adaptations of life on Earth is, seemingly, unending.  Probably every niche on this planet is used by at least one kind of plant, fungus or animal.  That came to my mind again while watching a nature documentary on you tube T V about life in the open ocean, narrated by David Attenborough.  As part of his narration, Attenborough noted that Columbus crabs are a half-inch, pelagic species that shelter among clumps of floating plants and trees that fell into the oceans, and under floating human-made debris, including lumber, discarded fish nets, collections of plastic objects and other objects.    

     This extraordinary, little crab's name is also unusual.  It is thought that these tiny crabs were first discovered by Christopher Columbus on one of his voyages west on the Atlantic Ocean.  He might have noticed them on plants in the Sargasso Sea. 

     As an interesting pelagic species, Columbus Crabs live exclusively in the open ocean, including the North Atlantic, between 11 and 32 degrees north.  When danger lurks, they have nowhere to swim, but they do have shelters in which to hide, as listed above.  And there, in those hiding places, these bitty crabs catch and ingest krill, tiny fish and other teeny edibles suspended in open ocean waters.  

     These interesting crabs can change their shell colors to match their surroundings, allowing them to blend into their niches for their safety.  Most of them are brown or yellowish, and each one has a white bar from side to side behind the head.  

     Columbus crabs can swim with all five pairs of legs, but they lack stamina for long distance traveling.  Sea turtles journey through the oceans, and when a Columbus crab spots a turtle near its sheltering home, it swims out to that turtle and hitches a ride on it.  Males do that, especially, to roam through the ocean in search of a mate.  If a male Columbus crab lands on a sea turtle that already has a resident female Columbus crab, the turtle is like a romantic cruise ship with a female, and bits of food on the turtle's shells and skin.  And there the pair of crabs might spawn eggs, or on a clump of vegetation or debris the turtle passed by in its travels.

     Columbus crabs are interesting little crustaceans that evolved a life style in open oceans, free from competition from crab relatives on shorelines and in salt marshes.  They developed their own life style in an extraordinary habitat.        

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