Vary in size, some of them up to just a few millimeters, such as crab peas, and some size as large as the Japanese spider crab, which is about four meters long leg
Males characterized by larger female claws, and females have a wide rounded belly
He can communicate by waving or drumming
It considered an aggressive animal towards its sexes, as there is a lot of competition between males to reach females
He likes to live in rock caves and holes and cracks, some live on the seabed, some prefer to live among coral reefs, or several kilometers deep in the sea
Crab is one of the favorite meals of many people, especially the people of East Asia. It is cooked and eaten in different ways. It contains a nutritional formula that is as beneficial as other marine organisms. The most important species are edible European crabs, blue crabs, mangrove crabs, lobster crabs and mud crabs. The multiplication of these species and hunting in large quantities to sell and eat.
Many fossils have found for this animal, and some fossils indicate extinct species
It considered a carnivorous animal. It eats worms and mollusks, algae is a staple food, and it eats bacteria, fungi, crustaceans, crustaceans, plankton and some species of fish, and its diet may be mixed between vegetarians and animals
In the breeding season, crabs cut off long migratory distances towards the ocean to lay their larvae. When the larvae hatch, they migrate in the opposite direction, and during their course, many of them fall.
The female male attracted by the use of pheromone, sometimes by audio or visual means
Some species have the ability to fertilize the sperm, storing sperm for a long period and using it to fertilize the oocytes