Image: Rebecca Dominguez
Imagine seeing a creature like the one in this photo climbing a tree or crawling on the ground in your backyard. Well, monstrous-looking or not, these colossal clawed creatures are actually crabs, and the largest living terrestrial arthropods. They reflect how terrestrial animals with large exoskeletons can actually grow. You can find them in many Indo-Pacific islands, specifically the coastal-forest regions, and they are called coconut crabs.
Could these oversized crustaceans have had a part in the death of American aviation pioneer Amelia Earhart?
Coconut crabs come forth irregularly at night to feed, loot, raid and plunder. The crab is known for its ability to crack or pound open coconuts with the strong pincers or two large chelae it possesses in order to eat the contents. It is related to the hermit crab: the two are from the same family, Coenobitidae, of the order Decapoda and the class Crustacea. However, it is the only species occupying the genus Birgus and is the largest crab on land.
Image: Mila Zinkova
How Do They Live?
Strangely, the crab is unable to live for any length of time in the sea. Though it has modified gills, the crab has adjusted extremely well to existing on land. It does return to the sea, however, as its body needs to maintain its salt balance, and the females must also go back there to relinquish their eggs. The creatures dwell in crevices within rocks, burrows made of sand, coral rock and porous limestone substrata along coastlines. The body of this slow-growing creature is split into four parts: cephalic lobe, forepart, trunk and opisthosoma. It generally emerges at night to feed. The soft white meat of the coconut forms the main part of the crab’s diet. However, it also eats simple foodstuffs such as fruit and leaves as well as more ‘extreme’ items like crustaceans’ exoskeletons that have been moulted. This may serve as a calcium source for the growth of the creature’s own shell.
Image: IMLS DCC
Amelia Earhart visiting a municipal airport in Springfield, Illinois on October 21, 1934.
They Can Smell and Are Titillated Like Humans
Smelling for these creatures is an interesting process. Since most crabs sometimes habituate the water, they possess specialized organs which are located on their antennas. These organs are called aesthetascs and function to define both the concentration and the direction of a given smell. Yet coconut crabs subsist on land, so their smelling organs look more like those that insects have, called sensilia. The necessity of locating smells in the air reflects convergence in the development of insects and coconut crabs – convergence being the occurrence of shared biological traits despite the fact that the different species’ evolutionary paths are dissimilar. The coconut crab has strong claws. A pinch or grasp of this creature’s grip will cause severe pain. In order to coax it to loosen its grip, mild titillation of the underside of its body using any kind of lightweight material causes it to diminish its hold. This trick was reported by Thomas Thomas Hale Streets and used by Micronesians of the Line Islands.
Newer discoveries hint at the coconut crab being responsible for legendary aviator Amelia Earhart vanishing. It is believed that both Amelia Earhart and her navigator landed on a distant South Pacific island. It is also believed that they died there. In 1940, researchers discovered a fraction of a skeleton on the island that matched the description of Amelia Earhart. Now, even more interesting clues are arising that seem to substantiate the idea that this is where she met her demise. The most compelling hypothesis currently under consideration is that coconut crabs overwhelmed her where she lay. Ric Gillespie, executive director of The International Group for Historic Aircraft Recovery (TIGHAR), believes a significant number of Earhart’s bones were removed by coconut crabs. Researchers carried out an experiment to validate whether the coconut crabs had a part in her demise.
Back in 2007, they used a small pig carcass to assess what the coconut crabs might have done. The bones were removed very quickly and scattered, according to Patricia Thrasher, TIGHAR’s president.
Image: Scott Mindeaux
Eat Them? Maybe
Considered a delicacy and an aphrodisiac, Southeast Asian people and Pacific Islanders enjoy consuming the coconut crab, for example as soup as seen here. People say it tastes like lobster or other crabs. The female coconut crab’s eggs are considered the most valued. This crustacean can be boiled or steamed and is found in various recipes, distinctively used in coconut milk. Plants are a part of the coconut crab’s diet.
Some of the crabs can be intrinsically poisonous due to poisonous plants being a part of their diet. Instead of killing the crabs, they can be fatal for those who consume them.