Hermit Crabs
(Decapoda)
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Animal Type
Invertebrates
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Exhibits
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Range
Africa
Australia
Europe
North America
South America
Atlantic Ocean
Indian Ocean
Pacific Ocean
Southern Ocean
Overview
There are over 500 species of terrestrial and aquatic hermit crabs. Terrestrial species live on land and visit the water to moisten themselves or to breed. Aquatic hermit crabs live in the water and occasionally hunt on land.
The back half of hermit crabs' exoskeletons doesn't offer much protection, so these clever crustaceans wear empty snail shells. They use their strong, curved abdomens to wrap themselves into a shell and will hide inside when threatened.
Hermit crabs molt at least once a year to shed their old exoskeletons and grow a larger, new one. Smaller hermit crabs molt as often as every other month, but each crab is different. They bury themselves to keep their squishy bodies safe and will even eat their old exoskeleton for extra calcium to strengthen their new one.
Despite their name, hermit crabs are social animals. They're often in large groups and will even line up to trade shells during molting season. But things aren't always civil. Hermit crabs will fight to the death for shells because they need them to survive.
At the National Aquarium, you can visit striped hermit crabs.
Quick Facts
Learn more about hermit crabs! Did you know there's a terrestrial hermit crab species that doesn't use a shell? Coconut crabs can grow up to three feet wide and weigh almost nine pounds. While juvenile coconut crabs wear shells, adults are too big for them and instead rely on their tough exoskeletons for protection. Coconut crabs eat fruits and seeds but also seek out larger prey like birds and rats. They can also crack open coconuts with their claws, hence their name!
Hermit crabs are found all over the world, except Antarctica. Terrestrial hermit crabs live in the woodsy areas near shorelines and visit beaches to hunt, breed and find shells. Aquatic hermit crabs live in salt or brackish water, found in bays, the ocean and even tide pools. In the Chesapeake Bay, you can find long-clawed, broad-clawed and banded hermit crabs.
As opportunistic omnivores, hermit crabs eat anything they can get their claws on, like plankton, parasites, fish and even other crabs!
These crustaceans range anywhere from half an inch to 3 feet long as adults! The largest aquatic species is the giant hermit crab, which can grow up to a foot long and lives in Queen conchs' shells.
Most hermit crab species are not currently endangered, but habitat loss caused by human activities puts populations at risk.
Hermit crab predators include birds, fish, sharks, octopuses, crabs and snails. But humans pose the greatest risk due to the pet trade, overhunting of larger species and habitat destruction. The next time you visit the beach, leave the shells where you find them! Hermit crabs depend on shells for survival and will, unfortunately, use marine debris, like bottle caps or plastic bottles, when they can't find shells.
Tours & Experiences Experience the Aquarium Like Never Before
Experience a 4D movie, explore behind the scenes, meet our experts and come face to face with amazing animals.
Explore Exhibit Residents
Learn more about the animals that share an exhibit with this one.
Striped Burrfish (Chilomycterus schoepfi)
Burrfish are covered with short, heavy spines that are always erect.
Moon Jelly (Aurelia aurita)
Their bells are luminous with a blue-grey transparent disk in the center and glowing, horseshoe-shaped organs.
Atlantic Horseshoe Crab (Limulus Polyphemus)
This species has 10 eyes scattered throughout its body.