japanese spider crab


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  • Location: Monterey Bay Aquarium, California, United States
  • Source: Monterey Bay Aquarium
  • Info: Live Japanese spider crab webcam at the Monterey Bay Aquarium in California, United States. The Japanese spaider crab is the largest living crab in the world. It occurs naturally on the seafloor along Japan's Pacific coast.

More info: The Japanese spider crab lives in the Pacific waters around Japan and is found at depths ranging from 660 feet (200m) to 1,800 feet (550 m)

The carapace, which is the main body cavity, is 12 inches (30 centimeters) across. The legs of the Japanese spider crab continue to grow even once it reaches adulthood and can span up to 12 feet (3.8 meters) from claw to claw. This makes the Japanese spider crab the world’s largest living crab.

The Japanese spider crab has ten legs which comprise of eight walking legs and two legs that have claws, known as chelipeds. The chelipeds of an adult male are considerably longer than his walking legs, while an adult female has chelipeds shorter than her walking legs. Japanese spider crabs may lose one or more of their legs if torn off by a predator or trawl net. These missing legs can regrow when the crab molts.

Japanese spider crabs will migrate to shallower waters during their mating season which is normally between January and April. They can lay up to 1.5m eggs at a time but only a few survive to hatch approximately 10 days later. They go through a larval stage after hatching and in this phase they are about 0.03 inches in size and transparent and legless.

Japanese spider crabs spend most of their time walking on the sea floor looking for food. Their diet includes dead or decaying fish, invertebrates, and algae.

This species belongs to a group of crabs termed “decorator crabs” which have been observed decorating their shells with sponges, plants, and anemones. This provides camouflage and allows them to blend in to their environment allowing protection from predators.