Robbers of the Shore
Written by Randi Lynn Mrvos
Photos by Gerald McCormack,
Imagine
you’ve been invited to go camping on an island. Everyone has pitched their
tents. And you’ve caught fish for dinner. But your cooking pan is missing! And
your silverware, too!
Not far from your campsite lives a creature that is rumored to steal shiny objects. It’s the coconut crab, the largest land-living arthropod in the world. Sometimes the coconut crab is known as the robber crab or the palm thief.
Coconut crabs vary in color from purplish-blue to
orange-red. They are found on the islands throughout most of the Indo-Pacific
region, between
Coconut crabs are crustaceans. They are related to lobsters, shrimps, barnacles, clams, and prawns. All crustaceans have several pairs of jointed legs. Crabs have 5 pairs of legs. The front pair of legs is used for fighting and grabbing food. The other legs are for swimming and walking. Coconut crabs have sharp pointed tips on their legs. The sharp tips help them climb up trees. They also have huge, powerful claws. These come in handy for crushing coconuts open to eat the flesh. In fact their claws are so strong that they can lift rocks weighing up to 60 lbs!
Like spiders, ticks, and insects, crustaceans are arthropods. All arthropods have an exoskeleton or hard body covering. Only the small, young coconut crabs use shells to protect their soft-skinned abdomen as they develop. When they grow larger, coconut crabs grow a hard skin and then abandon their shells.
Most crabs are usually no more than 6” long. But, coconut crabs grow to be 3 ft. long! They build burrows for their homes. As coconut crabs grow, they leave their existing burrow and search for a larger place to live. The largest crabs have the nicest homes. They burrow in sandy soil, tree roots, and logs of coconut trees. The burrows are cool and moist and protect the crabs from dehydration. The smaller coconut crabs live closer to the coral edges of the island. They rely on coconut piles and thick vegetation for protection and food.
Coconut crabs are omnivores—plant and meat-eaters. Their diet consists of coconuts, fruits, rotting leaves, as well as dead or injured animals. Sometimes they eat other coconut crabs. During the day, coconut crabs hide in their burrow. But they come out at night in search of food, a better home, or perhaps, for something to steal. So keep on eye on your pots, cans, wristwatches, and silverware. If it’s shiny, a coconut crab may be tempted to claim it as his own!