Japanese spider crab
A giant Pacific spider crab with a diver in the background
The Japanese spider crab can grow to be over twice the size of a human © Getty
There are around 60,000 species of crustaceans, and of these, the Japanese Spider Crab is the largest. With a whopping 3.7m (12 feet) leg span, they are considerably larger than a human. But despite their large size, they start life as microscopic planktonic larva, one of millions that the mother lays. Japanese spider crabs are mostly found off the coast of Honshū, a Japanese island.