Japanese Spider Crab

Japanese spider crab (Macrocheira kaempferi), are known to be the biggest arthropod on this earth that exists currently. These crabs have a ferocious and frightening appearance. They are also commonly known as "Japanese spider crab". About 700 types of spider crabs are found all over the world.
Japanese spider crab Physical Appearance
These Giant Japanese spider crabs can grow up to a size of 3.8 meters when measured from claw to claw. The size of their body is about (35 to 40) cm. Their body is orange and has white spots on their thin legs. These crabs are very popular because of their long legs and thus, give a frightening look among the human being. The Japanese spider crab has eight thin legs and two arms for feeding. The two thorns stick out between their eyes, which are situated on the front. They may or may not have a short tail.
Japanese spider crab Habitat
These crabs are found mainly in the off the southern coast of Japan. These are the main inhabitants of the Pacific Ocean surrounding the islands of the Japanese archipelago. They can be seen in the shallow as well as deep water measuring 50 meters and 600 meters respectively. In the older days, these crabs were thought to be the sea monsters.
Japanese spider crab Diet
The Japanese spider crabs are omnivorous and thus have varied diets. They feed mainly on small deep sea fish, plants, algae and on mollusks. These crabs have strong and large pincers, which help them to catch their prey easily.
Japanese spider crab Breeding / Reproduction
These Giant Japanese spider crabs lay their eggs at a depth of around 50 meters during the spring. Males of these species are larger than the females. They have separate sexes and the fertilization is internal. During mating, the spermatophore (a sac of sperms) is transferred in the females crab. After the fertilization, the females carry the sac of eggs in her body. The newborn species molt their skin several times until they get mature and have a permanent skin.

Japanese spider crab Species
There are four species of spider crabs, which belong to the Majidae family. The four species of the Japanese spider crab are as follows:
- Macrocheira kaempferi
These species are found in the Pacific Ocean within the region of Japan. These are the largest arthropod and can live up to 100 years. They have orange- colored body with white spots over it.
- Libinia emarginata
These crabs are found in the coastal region of North America. They are yellow or brown with white claws.
- Hyas
These species of the crabs are reddish-brown and has a pear shaped carapace. These are the inhabitants of Atlantic Ocean and North Sea.
- Maja squinado
These species of crabs are omnivorous and can live up to (5 to 8) years. Unlike other species they can mate with the female even if the female has not undergone molting. Other species wait for mating till the females exuviate.
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