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Another marine creature that lives in the
Red Sea`s waters and can be seen by diving in the Egypt's
beaches resorts, is the crab. Crab is a decapod crustacean that
belongs to the Brachyura infraorder and has 10 legs. Crabs have
a sideway walking and their thorax hides totally their reduced
abdomen. Their tail is very short and two of their legs have
gasping and large claws (chelae or pincers). Being
invertebrates, the crabs don't have backbones, but their body is
covered with exoskeleton that is also known as the carapace.
This carapace together with the outer shell provide the crabs
with support and protect them from the eventually predators.
Under the carapace are two cavities that hold the crabs` gills
through which the crabs breathe when they are under water. The
crabs` two eyes are located at the stalks' ends, their body is
flattened and they also have two feelers also known as the
antennae. The crabs are omnivores and their diet is made from
worms, algae, mollusks, detritus, bacteria, fungi and even other
crustaceans. The diet varies from one crab species to another.
Some of them prefer a diet made from an animal and plant
mixture. Although crabs lives in the all oceans of the world,
there are terrestrial crabs, too which can breathe on land due
to their modified and large cavities that function like the
lungs. From the 5,000 crab species, 4,500 are true crabs and 500
are hermit crabs, meaning that they use other's animals old
shell to protect themselves, because they don't have such a hard
shell. The Japanese spider crab is the biggest crab; its leg
spans up to 3, 7 meters. The Coconut crab is the biggest land
crab, its leg spanning up to 75 centimeters. The pea crab has
few millimeters. |
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