Crabs are cute when they're little. But what if they were so big that they could trap you underneath their legs? While it may not be heavy enough to pin down an adult human, the Japanese spider crab has legs long enough to walk right over you while you're lying down.
The Japanese spider crab can measure up to 13 feet from the tip of one leg to the other leg on the opposite side.
Not only is it the largest crab in the world, but it also has the largest leg span of any arthropod on the planet.
Despite its massive length, the crab only weighs about 40 pounds. And those long legs are pretty weak. One study found that about 75 percent of Japanese spider crabs are missing at least one limb. But the crabs can still survive even if they are missing up to three. The legs will often grow back when the crab molts.
The Japanese spider crab is also the world's longest-living crab, with a lifespan of up to 100 years.
If you live in the U.S., and this crab absolutely terrifies you, don't worry.
You don't have to be concerned about running into one at the beach. These crabs are only found off the east coast of Japan. They spend their time on the seafloor scavenging for dead animals that they can eat.
Japanese spider crabs are large enough that the only animal that routinely preys on them is humans.
Fishermen are not allowed to catch the crabs in the spring, during breeding season, but at all other times they can be fished. In recent years, catches have been declining, and fishermen have been moving into deeper waters in order to find more crabs.
Population data for the species is limited, so we don't really know whether they're in serious trouble. Perhaps if we get a better sense of their numbers, more fishing restrictions could be put in place.