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Crab Facts

Not a chance you already knew these.

Our love for crabs is as enduring as our love for SpongeBob memes. Here are 11 crab facts you probably didn't already know.

1. Crabs can be divided into two groups: true crabs and false crabs.

True crabs belong to a group (or, if you want to get really technical, "infraorder") of crustaceans called brachyura. You can recognize them by their classic body shape, like a flattened football with legs. False crabs include everything that isn't a brachyuran, including hermit crabs and Alaskan king crabs.

2. Horseshoe crabs aren't even crustaceans.

crab facts

They're chelicerates, more closely related to spiders and scorpions than true crabs. They also have six types of eyes and meet up for an annual orgy every spring in Delaware. (Seriously.)

3. A group of crabs is called a cast.

crab facts

And we're going to imagine that they're all aspiring to musical theater, thanks to Sebastian.

4. Crabs can cooperate to accomplish a goal.

One of the cutest examples of this is the phenomenon of hermit crabs lining up by size in a "conga line" to exchange shells. Researchers have also seen porcelain crabs, pistol shrimp and gobies live together to help each other keep watch for predators.

5. Some crabs have a special relationship with anemones.

crab facts


Boxing pom pom crabs, for example, gets their name because they hold sea anemones like boxing gloves, using them to protect their claws and pick up more food than they could alone.

6. Crabs feel and remember pain.

A 2013 study showed that crabs do not enjoy being shocked, and therefore they probably don't like being boiled alive either. Surprising?

7. Fiddler crabs can be right-handed or left-handed.

crab facts

You know the crab species with one tiny claw and one huge claw? Those are fiddler crabs. In rare cases, they can even be ambidextrous, with two huge claws.

8. There is an Isle of Crabs.

crab facts

The Australian Christmas Island is so densely populated with a species called Christmas Island red crabs, it actually has crab-specific traffic signs.

9. Some crabs climb trees.

There's the coconut crab, the largest species of crab, which can grow to over 3 feet long, eats birds and looks like a super-powerful spider. There's Kani maranjandu, which looks like an elegant yet equally blood-chilling spider. And then there's Haberma tingkok, which looks like a warty frog. Yeah, we hate this too.

10. Yes, crabs can live on land.

crab facts

But they have to keep their gills moist in order to breathe.

11. The smallest crab is the size of a pea.

It's called the pea crab, it's a parasite and you might find one the next time you eat an oyster. Yay, crabs.

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