kids encyclopedia robot

Japanese spider crab facts for kids

Kids Encyclopedia Facts
Quick facts for kids
Japanese spider crab
Macrocheira kaempferi.jpg
Scientific classification
Kingdom:
Phylum:
Subphylum:
Class:
Order:
Infraorder:
Superfamily:
Family:
Inachidae
Genus:
Macrocheira
Species:
M. kaempferi

The Japanese spider crab (Macrocheira kaempferi) is a special type of ocean crab. It is the only member of its genus called Macrocheira. You can only find this amazing crab in the waters around Japan.

This crab is famous for having the longest legs of any arthropod (a group of animals with exoskeletons, like insects and spiders) in the world! Its legs can stretch up to 3.8 meters (12 feet) long. That's longer than a small car! It can also weigh up to 41 pounds (19 kg). People in Japan sometimes catch these crabs for food, as they are considered a special dish.

What Does the Japanese Spider Crab Look Like?

Japanese Spider Crab
Japanese Spider Crab

The Japanese spider crab has the longest leg span of any arthropod on Earth. Its legs can reach up to 3.8 meters (12 feet) across. Even though its legs are super long, its main body is only about 15 inches long.

This crab has eight long legs for walking. It also has two special arms that it uses for finding and eating food. Each of these feeding arms can be about 1.5 meters (5 feet) long! The crab is usually orange with white spots on its legs. Even though it looks a bit scary, this crab is actually known to be very gentle.

Its hard outer shell, called an exoskeleton, helps protect it from bigger ocean animals like octopuses. Japanese spider crabs also use a clever trick to hide. Their bumpy shell helps them blend in with the rocky ocean floor. To hide even better, they often put sponges and other small sea creatures on their shells. This makes them look like part of the seabed.

Where Do Japanese Spider Crabs Live?

Laika ac Japanese Spider Crab (8576014299)
Japanese Spider Crab

You can find the Japanese spider crab in the Pacific Ocean near the Japanese islands of Honshu and Kyushu. They often live in places like the Sagami, Suruga, and Tosa bays. They are also found off the coast of the Kii peninsula.

These crabs usually live in very deep parts of the ocean. They can be found at depths up to 750 meters (2,500 feet). That's deeper than many tall buildings! Once, a Japanese spider crab was found far south in Taiwan. However, this was probably a rare event. It might have been carried there by a fishing trawler or very strong ocean currents.

What Do Japanese Spider Crabs Eat?

The Japanese spider crab is an omnivore. This means it eats both plants and animals. It also acts like a clean-up crew in the ocean. It often eats dead animals that have sunk to the ocean floor.

Some spider crabs like to scrape the ocean floor to find plants and algae to eat. Others are strong enough to open the shells of mollusks, like clams, to get to the soft animals inside.

Japanese Spider Crab Life Cycle

Japanese spider crab
This crab specimen from the American Museum of Natural History measures 3.8 metres (12 ft) across its outstretched legs

Female crabs carry their fertilized eggs attached to their bodies. They hold onto these eggs until they are ready to hatch. When they hatch, the baby crabs are tiny and float in the water as plankton.

A female crab can lay a lot of eggs, sometimes up to 1.5 million eggs in one season! These eggs usually hatch in about 10 days.

Fishing and Protecting the Japanese Spider Crab

Fishermen usually catch these crabs using small nets called trawling nets. In recent years, the number of Japanese spider crabs has gone down. This is partly because of too much fishing, which is called overfishing. Because of this, fishermen now have to go into deeper waters to find them. The crabs that are usually caught have a leg span of about 1.0 to 1.2 meters (3.3 to 3.9 feet).

Many people are working hard to protect these amazing crabs. One way they are trying to help is by releasing young crabs that were raised in special facilities back into the ocean. This helps to increase the wild population.

Also, there are special laws in Japan to protect the crabs. From January to April, fishermen are not allowed to catch spider crabs. This is their typical mating season, and during this time, they move to shallower waters where they are easier to catch. This rule helps the crabs reproduce and allows young crabs to grow bigger before they can be caught.

Images for kids

See also

Kids robot.svg In Spanish: Cangrejo gigante japonés para niños

kids search engine
Japanese spider crab Facts for Kids. Kiddle Encyclopedia.