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The Coconut Crab - the World's Biggest Land Arthropod |
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How the Coconut Crab Lives
The Coconut crab, which scientists call Birgus
latro, is the largest land-living arthropod
in the world - in fact it's the largest of all the invertebrates that
live on land! It
has a body length of up to 40cm (15 inches) and it weighs up to 4.1kg
(9 lb) and a leg
span of more than 90 cm (1 yard). The males are generally bigger than
the
females.

The Coconut Crab is the World's Biggest Land Arthropod
They
can live more than 30 years. Their body is divided
into a front section which has 10 legs, and an abdomen. The frontmost
pair of legs has large claws which the crab uses to crack
coconuts - that's how it got its name. These claws can lift objects up
to 29 kg (64 lb). The next two pairs of legs are large, powerful
walking legs
which enable the coconut crabs to climb vertically up trees like
coconut palms. The fourth pair of legs is smaller with pincers like a
pair of tweezers
at the end. It is used by young crabs to grip
the inside of a coconut husk to carry for protection. Adult
coconut crabs use this pair for walking and climbing. The
last pair of legs is very small and it is use to clean the breathing
organs. These legs are usually held inside the cavity containing the
breathing organs.
The coconut crab is sometimes
called the Robber Crab or Palm Thief because some say the crabs like
to steal shiny items such as pots and silverware from houses
and tents. It can be found in tropical islands of
the Indian and Pacific Oceans.
Coconut Crabs are Hermit Crabs

The Coconut Crab Climbing a Coconut Tree
Coconut crabs are a kind of hermit crab - most
hermit crabs have a soft
abdomen, and use snail shells to protect themselves. However, the
Coconut Crab is so large that there are no snail shells big enough!
Only young Coconut Crabs use snail shells. As they grow older, they use
bits of coconut shell, and when fully grown, their abdoment gets harder and they don't use anything at
all. Hermit crabs are not really crabs at all, but belong to a group of
crustaceans of their very own. This group is included, with crabs and
lobsters, into a larger group of crustaceans called Decapods (which
means "10-footed"). So, as well as being the biggest land arthropod,
Hermit crabs are
- The world's biggest land crustacean,
- The world's biggest land decapod
crustacean and
- The world's biggest hermit crab!
Coconut Crab Diet
The coconut crab cannot
swim. They use a special lung to
breathe. They have an excellent sense of smell and are able to
detect smell from a distance. The smell of rotting meat, bananas, and
coconuts,
all potential dinner, catch their attention especially.
Apart from coconuts, the crabs also eat
fruit and a
range of other organic material,
including leaves, dead animals and the shells of other creatures.
Coconut Crab Life Cycle
The female coconut crab releases the eggs into
the ocean at high tide.
The
crab larvae will float in the ocean for about 28 days. After
this
larval stage they will lose their ability to breathe in water. The
young coconut crabs are quite flexible. About four to eight
years after hatching, the
coconut
crab matures and can lay eggs.
People and Coconut Crabs
Meat from coconut crabs is
considered a delicacy by Pacific islanders. It
taste
similar to lobster and crab meat. The coconut crab can be
boiled,
steamed or cooked in coconut milk. However, the meat is
sometimes
toxic, if the crab has made a habit of eating
poisonous plants. Not surprisingly, claws that can crack coconuts can
also give a painful pinch to an incautious person - and the crab may
continue to hold on tightly to its
victim. Some people say that rubbing the crab tummy
may cause it to loosen its grip - but it's certainly better not to let
the crab bite you in the first place!
Coconut Crabs are sometimes kept as pets,
for example in Japan, especially when they are not fully
grown. But you will definately need a sturdy cage
that they
cannot dismantle with their
powerful claws.
The numbers of Coconut crabs many places
has gone down, and they've even died out completely in some places.
This is because people have hunted them too much and destroyed the
places they live. Now, the Coconut Crab is
a world-wide protected species.
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