Coconut Crab Habitat

Coconut piles provide food for young crabs as well as protection. Larger coconut crabs use burrows under tree roots and logs for a home instead of carrying around a shell like other hermit crabs. Burrows help to protect these animals from dehydration because a burrow is more moist and cooler than the surrounding environment. Coconut crabs usually remain hiding in their burrow or under foliage during the day and come out at night to find food or a better home. Studies suggest that the larger crabs remain close to their burrows because they are already positioned in the best areas, where as small crabs will venture across an island in search of food or a better place to hide. As these animals grow in size, they depart from the safety of their existing burrow to find a larger place to live. Since coconut crabs are not depedent on snail shells for a home as the progress into adulthood, they are capable of growing to extremely large sizes. Coconut crabs are the largest terrestrial arthropods currently living on earth. Therefore, it is not surprising that the largest crabs, which are also the most dominant, live in the nicest burrows. Ideal burowing areas are those found in sandy soil because it is easier for a crab to dig. That is why smaller crabs often live closer to the coral edges of the island, where it is more difficult to build a nice burrow. The juvenile coconut crab diet differs from that of the adults, partly because of where they reside. The juveniles generally live under coconut piles or dense vegetation which provide the leaf and plant litter that they feed on. The adult coconut crabs are omnivores. They forage by night for fruits, rotting leaves, coconuts, and dead or injured animals, as well as other coconut crabs.

Originally, coconut crabs were found on islands throughout most of the Indo-Pacific Region. The crab's slow rate of growth as well as late sexual maturity (six to eight years of age), has made them very susceptible to over exploitation. Recently they have become more rare because are a delicacy and have been captured at a quicker pace than they can reproduce. Coconut crab populations on Palmyra are high relative to other islands that they inhabit because the human threat is nonexistent. However, predation by non-native rats pose a significant threat for these crabs on Palmyra atoll.