With a length of about 1 m, coconut crabs are the largest terrestrial arthropods in the world. Although Japanese spider crabs are larger in size, they are aquatic.
Coconut crabs, the largest creatures of any terrestrial arthropod, can break open coconut shells and hunt rats with their strong pincers.
Researchers have not determined the exact number of coconut crab species in the world. Incomplete statistics from the International Union for Conservation of Nature cannot help them confirm that the “giant king” of terrestrial arthropods is on the brink of extinction.
Coconut crabs live on small islands in the Indian and Pacific Oceans. Their name is coconut crab, but the food of this arthropod is quite diverse, including many types of fruits and smaller crabs.
When eating coconuts, crabs use their strong pincers to peel the outer shell. Then, they repeatedly hit the coconut’s skull until it broke.
This giant crab lives in underground burrows lined with coconut shell fibers. Unlike all other types of crabs, coconut crabs live mainly on land and only return to the sea when the breeding season comes.
“Since ancient times, people have hunted coconut crabs,” said Heather Koldewey, working at the Zoological Society of London, England. Now, they have become easy prey for rats. Heather and her colleagues have begun the first survey of the number of coconut crabs. They searched for them on three islands in the Chagos archipelago, Indian Ocean.
On small islands, where vegetation is scarce, rats will hunt coconut crabs more. However, many people have witnessed the opposite scene when coconut crabs “eat” hunters.
On the Chagos Islands, the coconut crabs will be safe. “This archipelago is a strict marine reserve so coconut crabs will be safe here,” said Heather.