Japanese Spider Crabs are the biggest arthropods in the world in terms of legspan. Measuring 3.8 metres (12 ft) from claw to claw, they daintily tip-toe over the opposition. At 41 pounds (19 kg) they are not the heaviest and, with an actual body just 40 cm (16 in) wide, it's truly those sprawling legs that make their mark.
As is so often the case, it's the males who have the overly unwieldy sticky-out bits. They have curiously puny claws at the end of stupidly long chelipeds, or what you might call 'arms'.
In males these chelipeds are longer than the legs. Females have them shorter than their legs, appearing less nightmarish but more sensible. Nightmares are seldom sensible.
|Image: Smithsonian Institution, National Museum of Natural History, Invertebrate Zoology|
A claw. Doesn't it look like a bird that has a lot of chewing to do?
The claws at the end are really small in comparison, but they look like some kind of bird's beak full of molars. If you remember our very own Arrow Crab, these giants are close relatives. It's just that the Japanese Spider Crab looks to me more like a futuristic bomb disposal robot. They can live for up to 100 years so they might even see that happen.
What their distribution lacks in surface area is perhaps made up for by depth; they can be found at depths between 50 metres (160 feet) all the way down to 600 m (2,000 ft).
Their diet of shellfish and carrion scavenged from the ocean floor stands them in good stead, puts a foot in the door and gives them a leg-up to survival in the gloom of the Twilight Zone.
|Image: Biopix, N. Sloth|
Pure ballet! Chest out, stomach in, ready for action.
|Image: Wendell Reed via Flickr|