10 Fun Facts About Crabs
- Jun 18
- 2 min read
Updated: Jun 21
With their sideways scuttles, powerful claws, and tough shells, crabs are some of the most recognizable creatures in the animal kingdom. But did you know these crustaceans are also incredibly diverse, clever, and even capable of regeneration? Whether crawling along the ocean floor or hiding in tide pools, crabs have plenty of secrets waiting to be discovered.
In this post, we’re diving into 10 fun and curious facts about crabs, from their incredible range in size to their unique ways of communicating.
Fun Facts About Crabs
Crabs Have 10 Legs (Decapods)
Crabs belong to the decapod group, meaning “ten-footed”, with eight walking legs and two front claws (chelae) used for feeding and defense.
Protected by an Exoskeleton
Crabs are encased in a hard external shell called an exoskeleton, made of calcium carbonate and chitin. This armor protects them and allows muscle attachment.
They Mostly Walk Sideways
The leg joints of crabs are designed for lateral movement, making sideways walking their most efficient mode. However, some species can move forward, backward, and even swim.
Found Nearly Everywhere
Over 6,700 species exist! Crabs are found in oceans, rivers, freshwater bodies, and even on land—like the massive coconut crab.
Size Range: Tiny to Titanic
The smallest pea crabs measure only a few millimeters, while the Japanese spider crab can span up to 4 meters (13 ft) across.
Amazing Ability to Regenerate Limbs
If they lose a limb, crabs can regrow it over time through a process called autotomy, shedding it to escape predators.
Smart Communication
Crabs use claws, drumming, and chemical pheromones to communicate, especially during courtship and competition.
Omnivorous Diet
From algae and plankton to mollusks and smaller crustaceans, crabs eat a wide range of foods, even detritus, playing a major role in their ecosystems.
Molting for Growth
Crabs must shed their exoskeletons through molting to grow. After molting, they’re vulnerable until the new shell hardens.
Masters of Camouflage
Some crabs, like decorator crabs, attach shells, seaweed, and even living organisms to their bodies for camouflage and protection.
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