Not to be confused with Crab Spiders.
Imagine giant spiders with 13-foot legspans and scorpion-like pincers on their front legs. What sounds like terrifying creatures from a monster movie are the real things-they're called spider crabs. Though they look the part of deadly attackers, spider crabs spend most of their time eating algae and trying to avoid most predators. They target harmless, slow-moving prey like marine worms.
Sidewalk Only: These crabs have long legs that give them the look of big, underwater spiders. The Japanese spider crab is the biggest crab in the world, with a leg span of up to 13 feet. The crab's leg joints are hinge so that the creature walks sideways across the ocean floor.
Spiked: A spider crab's round shell is hard, thick and covered with spikes. The spikes alone deter predators that don't want to cut up the insides of their mouths, but those that do attack have trouble cracking the crab's tough armor.
Crab Cravings[]
Spider crabs come in a variety of sizes. This crab's legspan of about four feet is only one-third the size of the largest crabs, which have 13-foot spans.
All spider crabs, big and small, have strong pincers on the ends of their front legs. Most of the time, these creatures use them to snip pieces of algae, sponges or dead fish and bring the food to their mouths like someone using two long cranes. The crabs also like to snatch slow-moving prey, such as worms, from the ocean floor. Some species even climb onto plants, latch on with their hind legs and wave their claws toward their mouth to sweep plankton into their five pairs of jaws.
Friend of Anemones: When it's time to rest, some species of spider crab seek out the protection of a snakelock anemone, which has long, stinging tentacles. The crabs are immune to the snakelock's strings, and its tentacles protect the crabs from enemies.
Crabby Lovers: Every summer, spider crabs gather by the hundreds in shallow water to breed. Males from a circle around females, and constantly try to climb over each other to get to the middle and fertilize a female's eggs.
Like a Rock[]
Spider crabs are hard to find, even though they're all over the oceans. They do a great job of camouflaging themselves by picking up pieces of underwater plants that stick to tiny spines on their legs. Plus, the crab lets algae and even small creatures grow on their shells so, when still, the crabs look like nothing more than a rock.
Trivia[]
- The spider crab is featured as prey in the multi-panel illustration on the back of the Wolf Fish card.
- The spider crab is used as part of the example creature in Build-A-Beast on Monster Mania 60.