Japanese Spider Crab Size report

Spider crabs are a type of sea crab; they have a hard shell and the most extended front claws in all species of crabs and are named for their resemblance to spiders' appearance. There are many raised spines on the spider crab shell and sea anemones attached to the spider crab shell. Although they have long claws, they are usually slow and easy to catch. Most spider crabs are scavengers.

The Japanese Spider Crab, known scientifically as Macrocheira kaempferi, is the largest spider crab and the largest arthropod in the world, living in the Pacific Ocean near Japan. The head is beak-shaped, and the body is generally covered with hairs and spines and attached to seaweed, sponges, or other organisms; secretions from the crab's mouth stick these substances to the body.

Japanese spider crabs live in the deep waters of the Japanese waters, where they spend their entire lives and can live up to 100 years old. In 1921, the largest Japanese spider crab was caught, weighing 41 pounds (18.6 kilograms) and having a wingspan of 19 feet (5.8 meters). This post will describe more details about the size and characteristics of this huge spider crab.

Size and Characteristics of Japanese Spider Crab

The body of Japanese spider crabs is oval or pear-shaped, with dark orange or light brown carapaces covered with spines. The crab legs are orange with white spots. Males are larger than females, and their chelipeds and claws are larger than females. The male's chelipeds are longer than his walking feet, while the female's chelipeds are much shorter than his walking feet. Males have triangular bellies; females have wider abdomens to hold their eggs.

Although they may look like giants, they are gentle creatures. They are classified as arthropods because they have no dorsal spine, no external skeleton, and multi-jointed appendages, namely their ten legs. These giant crabs are found on the Pacific coast near Japan, mostly limited to the Japanese archipelago, usually between 30 and 40 degrees north latitude. Some have also been found in the Russian Far East, the coast of Australia, and the eastern coast of Taiwan, China, where these giant crabs can expand their range more because of trawlers or extreme weather.

Japanese Spider Crab Average Size

Adult Japanese spider crabs weigh 16 to 20 kilograms, and their carapace is only about 40 centimeters long, but their claws are more than 4 meters wide when fully extended. The Japanese spider crab's carapace remains basically the same in size as adults, while its walking and cheliped legs continue to grow with age.

Living Habits

Japanese Spider crabs live in the deep sea with a water temperature of about 10 degrees Celsius all year round. Most often live on continental shelves and rock bottoms, generally at a depth of 150-300 meters. They appear only in the breeding season in shallow waters of about 50 meters. Feeds on fish; although they crawl slowly, their large, sharp pincers are quite agile. To find the target of the attack, giant claw crabs will quietly lurk on the seabed, using the eyes and the shock sensors in the body to distinguish the objects around them. Japanese spider crabs are omnivores and usually roam the seabed, picking up carcasses, decaying tissue, etc., for food.

Life Cycle

They usually live in the deep sea and only come to the shallow sea to lay their eggs in spring. Japanese spider crabs mate in early spring, from January to March. The incubation time is about 10 days, but the exact growth time is unknown. Japanese spider crabs can live up to 100 years in their natural environment.

Japanese spider crabs molt 15 to 20 times in their lifetime. The day before molting, spider crabs begin to absorb seawater in large quantities, expanding their bodies to open up their old shells so that they can escape from the cracks in the old shells. The entire molting process takes about 15 minutes.

Final Words

People prefer the nickname "killer crab" for giant claw crabs to the tongue-in-cheek scientific name. It is just a misunderstanding. Crabs do not have the superpower to kill and will not take the initiative to attack humans. Although the claws of Japanese spider crabs are intimidating, they are fragile and easily broken. According to reports, spider crabs with three broken walking legs can still survive. Occasionally, broken legs can be recovered during molting.