NEVER SHAKE HANDS WITH A COCONUT CRAB

 NEVER EVER SHAKE “HANDS” WITH A COCONUT CRAB

This type of crab is usually referred to as the “robber crab” or “palm thief.” It is a terrestrial species of a giant hermit crab, and is the largest known terrestrial arthropod. It weighs up to 9 pounds (4.1 kilograms). Its body length is up to 3 feet. It is found on islands all across the Indian and Pacific oceans. Unfortunately, it is a threatened (vulnerable) species, primarily because of human activities. It is not aggressive toward people, but, of course, it will defend itself, if provoked. They are also good climbers, and can climb up into palm trees.

Their carapace (“shell”) can be blue/black, gray, orangish brown, red or reddish), purple, or even yellowish. There can also be spots and streaks of variable color on the exoskeleton (carapace). 

Fig. 1: A hand-drawn/colored illustration of a coconut crab (from plate 4 in a 1849 book) (see References below). 

Figs. 2 and 3. Restriction free, internet-derived (creazilla.com) and royality-free images of two species of living coconut crabs.

Juvenile coconut crabs might typically use empty-gastropod shells for protection, but adult specimens are not “shell carriers.”Juveniles of coconut crabs, furthermore, live in the water, whereas the adults become only air breathers.  Coconut crabs are omnivores (i.e., they can eat both plants and meat). They especially like fleshy fruits, nuts, seeds, and pith of fallen trees. They are also cannibalistic.

The claws of coconut crabs claws are strong enough to be able to rip open a coconut, as well as take a human finger off. The "cracking force" of their claws can be greater than 1500 newtons (note: a grizzly bear has only 1410 newtons of force in its claws).

Coconut crabs, like all crabs, have to periodically molt (shed) their exoskeleton, in order to grow larger (and you think you have problems!). The adults usually hide (from 3 to 16 weeks) in burrows that they dig, up to l m (3.3 feet) long, while the molting process is taking place because these animals are very vulnerable during molting. Coconut crabs can live to be 60 years old!

Their eggs are placed in the sea. The larvae take 3 to 4 weeks before settling on the ocean floor. Coconut crabs are also adapt at attaching their larvae to floating logs.

Classification: 

Phylum Arthropoda

Class Malacostra

Order Decopoda

Family Coenobitidae

Genus Birgus

Type Species B. latro

The fossil record of coconut crabs is Miocene to Recent.

Coconut crabs can eat birds, and they can also eat carrion and other organic material. Hence, early postings on the internet commonly inferred that the famous aviatrix, Amelia Earthart, whose plane disappeared over the Pacific Ocean, while she was attempting to fly around the world in a small plane, might have been eaten by coconut crabs, if her plane had crashed on a tropical island. Today, some internet postings state this assertion as a fact, that indeed she was eaten by such crabs, but there is not a shred of evidence to back up this assertion! This is a prime example of how false information can spread via the internet! So, as always, be informed and do not fall victim to unproven facts.

References

1849. Dictionnaire d’Histoire Naturele. [I found this reference online at en.m.wikipedia.org].

2025. Wikipedia.