Beautiful coconut crab specimen
Like 95% of all animal species, the coconut crab (Birgus latro) belongs to the invertebrates, and together with insects, arachnids and other crustaceans, makes up the division of arthropods. So far, so good and not very unusual. However, it is also the largest land-living arthropod in the world.
Now you see it…
The coconut crab so lovingly clutching the trash can in this picture might be confused with a particularly realistic piece of art if it weren’t so bizarre.
… now you don’t – well, sorta
As is typical for many invertebrates, coconut crabs have exoskeletons, external skeletons that enclose the soft tissues and organs of the body. Given that coconut crabs can reach a weight of 14 kg (30 lbs) – roughly the weight of a four-year-old child – they represent the upper extent of how big terrestrial animals with exoskeletons can become in today’s atmosphere. And given that they can also reach lengths of up to 1.8 m (6 ft), they’re scarily big!
A brown and a blue coloured coconut crab in Bora Bora
The coconut crab is named after its ability to crack coconuts with its strong pincers to get to the coconut flesh inside. Though generally nocturnal and therefore in hiding during the day, coconut crabs are known to forage even in human habitats to look for food. As rumour has it, they also look for shiny objects, which has brought them the nickname robber crab – even their Latin name latro means robber.
Used to clinging to palm trees…
Of the coconut crab’s 10 legs, it’s the front-most pair that is the strongest, with claws used for cracking open coconuts and lifting weights of up to 29 kg (64 lb) – double its own weight!
Coconut crabs vary in size and colouring: blue coconut crab
Unlike other crabs, coconut crabs cannot swim and therefore have no need to smell underwater. Their antennae, made to trace smells over long distances, look more like the smelling organs of insects. Their excellent sense of smell works overtime whenever they detect any of their favourites – rotting meat, bananas or coconuts.
As this map shows, coconut crabs can be found in the coastal areas of most of the world’s southern oceans; red dots indicate primary and yellow dots secondary places of settlement.
Juvenile coconut crab in shell
Yet even size cannot protect an animal from extinction, and though the coconut crab can defend itself sufficiently from predators of the animal kind, it’s not so lucky with those of the human variety. Since word got out that coconut crabs are edible, and are considered a delicacy or even an aphrodisiac in some parts of the world, regional extinctions have been reported. However, conservation efforts are underway to maintain local coconut crab populations.