The rarest crab in the world is the coconut crab. Coconut crabs are a type of hermit crab, and they get their name from their ability to crack coconuts with their powerful claws. Coconut crabs are found on tropical islands in the Indian and Pacific Oceans, and they are the largest land-living arthropods in the world. They can grow up to three feet long, and they weigh up to nine pounds.
Coconut crabs are nocturnal creatures, and they spend most of their time in trees or burrows. They are excellent climbers, and they use their claws to help them climb up trees and cliffs. Coconut crabs eat fruits, nuts, seeds, leaves, birds' eggs, small reptiles, and dead animals that they find on the ground. They have been known to kill chickens and rabbits for food.
Coconut crabs mate during the wet season (usually October to December), when males compete for females by fighting each other with their large claws. The female lays her eggs in a burrow on land or in a tree hollow near the sea; she then covers them with sand or soil until they hatch about two months later. The young coconut crabs look like miniature adults; however, they lack developed claws and must molt several times before reaching full size.
Coconut crabs are hunted for food by humans as well as animals such as pigs and dogs; however, because of their slow growth rate (it takes them about five years to reach maturity)and low reproductive rate (females only produce about 50 eggs at a time), populations of coconut crabs have been declining over time due largely to overhunting pressure.. As a result ,the IUCN has listed this species as "vulnerable" on its Red List of Threatened Species