How many legs do crabs have what is their functions

How Many Legs Do Crabs Have?

So, how many legs do crabs have? Because along with crayfish and all other types of marine insects, crabs make up the biggest group of arthropods and are also classified as crustaceans of the infra order Brachyura.

Essentially, an infra order is a taxonomic category. The phylum Arthropoda, which has the most members on Earth and accounts for over 75% of all living creatures, includes all crustaceans as members.

Crabs are on land and in many sorts of water, including freshwater and the ocean.

Despite the diversity, crabs have particular traits and abilities that set them apart from other organisms of a similar kind.

Before a few million years ago, crabs were not in existence. They are present in nearly all aquatic habitats.

The world’s oceans, pure water, and even dry ground are home to around 6,793 different species of crab.

They also move together in the water—most of the time, when migrating or looking for food, hermit crabs form groups.

Also read: What Do Silverfish Eat And How Do They Find Foods

What Are Chelipeds?

How many legs do crabs have? What names can you give crabs’ oddly formed legs?


Fiddler crab males have large claws. These male crabs wave their feet in greeting when they come across other crabs.

Compound eyes on stalks are a feature of them. Hermit crabs can see things next to and behind them because of these eyes.

In the dim light, their eyes can quickly detect UV radiation.

The limb with the giant claw is the main cheliped. Typically, “cheliped” refers to the entire stem, not the foot.

Crabs have large claws called chelipeds that they employ for defense and catching prey. The species’ four terminal segments each include a pair of walking legs.

The first five abdominal segments each feature a swimmeret, which is a structure that moves water and aids in reproduction.

The second and third pairs of the hermit crab’s five pairs of legs are for walking. They have a robust exterior covering.

The shell, which is from a seashell, is taken around by a hermit crab. Additionally, they have very little tail that projects.

Within 24 months, a crab typically matures and reaches maturity. The inability of the shell of these crustaceans to expand as the crab grows frequently causes the surface to shed.

What Do Crab Legs Look Like?

How many legs do crabs have? Under the carapace, the thorax and head are in conjunction.

crab leg

A crab has two claws called chelae and has an exoskeleton that is robust and typically made of mineralized chitin.

These creatures have claws on the tips of their front legs. These claws function in a manner akin to pincers.

Technically speaking, pincers are a two-part instrument that works well for grasping objects.

Crabs fight with, hunt with, and shred flesh with their pincers. It can hurt if a pincer has ever bitten you.

Hermit crab legs have modifications for various uses. These species’ lengthy front legs have evolved into pincers, or chelipeds, as they are known scientifically.

The crab’s surviving legs develop into swimmerets or pleopods, tiny swimming appendages.

When walking, king crabs can effortlessly fold their last pair of legs beneath their bodies. These animals employ those legs to help sperm migrate and even to warm developing eggs.

Until the eggs are fully mature, the crab always retains sperm. After the female keeps the eggs and carries them in her abdomen until they hatch, the eggs fertilize.

Some crab species, such as the snow crab, have crisp shells on their legs. You only need your hands to crack and open them!

The left or right claws of most crab species are more significant than the other. The left-handed variety is the most common, particularly in left-clawed hermit crabs.

How Many Legs Do Crabs Have?

how many legs do crabs have

The word “crab” literally translates to “ten feet” and refers to the group of sea creatures with thick shells that make up the order Decapoda.

Except for a few specific subgroups, almost all crabs have ten legs. Horseshoe crabs, members of Chelicerata, are closely related to spiders and have eight legs.

The majority of crabs resemble crayfish and lobsters.

The fact that crabs have ten legs distinguishes them from ticks of the Acarina order, centipedes of the Chilopoda class, spiders of the Araneae order, millipedes of the Diplopoda class, and scorpions of the Dromopoda subclass.

All decapods have ten legs, five of which are bilaterally symmetrical on each side.

While swimming, some legs are modified to do tasks other than walking, such as self-defense and food acquisition.

The front pair is in the shape of powerful grasping claws, while the last four teams are for movement.

The animals with pincers move more quickly if they move sideways. Therefore although crabs can move slowly forward, they prefer to scurry sideways.

Do All Crab Species Have The Same Legs?

How many legs do crabs have? True crabs have five pairs of legs, making ten legs, along with other animals near them.

how many legs do crabs have

A depressed carapace is a characteristic of true crabs. However, some of their legs can do different tasks.

They can use those legs for swimming, food collection, self-defense, and other activities in addition to walking.

While the other four pairs are for walking, the front pair of legs are potent and contain claws that help grip when attacking.

Each crab in the Decapoda order has ten legs arranged in five pairs. It includes the suborder Brachyura, which also contains actual crabs.

The Anomura subphylum, which contains king crabs, hermit crabs, and squat lobsters, is also a part of it.

But it’s essential to remember that horseshoe crabs are more closely related to spiders than other crabs.

These aquatic creatures belong to the Xiphosura order and have 12 legs, making them sea creatures rather than crustaceans like crabs.

Crab species come in a variety of shapes and sizes, and their legs have evolved to serve a variety of purposes.

In addition to using their legs to transmit sperm, king crabs curl their legs beneath them while they walk.

The claws on the extremities of the legs of fiddler crabs come in a variety of sizes, and they utilize them to catch prey as well as to defend and fight off opponents.

Japanese spider crab. Despite having a name that contains the word “spider,” it is a crab.

Their legs are so long that, when fully extended, they may measure 12 feet (3.6 meters) from claw to claw.

The lower legs of swimming crabs, such as the flying crab, are flattened and used as paddles while swimming.

What do crabs eat?

How many legs do crabs have? Crabs consume various meals and typically use their claws to dissect their prey’s bodies.

Sea-dwelling crab species consume red and green algae, decaying debris, dead shrimp, and fish.

These marine animals typically consume flesh that is tender and delectable.

Additionally, they prey on marine snails, devour them, and remove their delicate shells.

Have crabs always had ten legs?

Crabs are among the most prevalent land-based insects.

Except for horseshoe crabs, which have just eight legs, and spiders connected with other groups (Horsfield’s Greenia), they typically have ten legs.

Decapods all have centralized neural systems and Biramous legs, two characteristics that make them viable in water but not on land, where most of them live.

Their enormous claws complement the strong exoskeleton that covers the segmented body of crabs.

Horseshoe crabs are more primitive than genuine crabs, but their morphological resemblance to other members of the order Decapoda led to the initial attribution of the name “crab” to them.

Horseshoe crabs first emerged 450 million years ago, and because of how little their anatomy has altered, they are also “living fossils.”

What Function Do the Different Leg Types in Crabs Serve?

Distinct limb kinds serve different functions in crabs.

Claws on the two front legs are utilized for fighting and grabbing prey. The crab can move around its habitat with the assistance of its other eight legs, which aids in walking.

Because it can walk and quickly grasp prey, the crab’s structure makes it more effective in its habitat. The crab’s many legs also aid in self-defense against enemies and rivals.

The crab’s walking legs and claws allow it to face an enemy or flee from danger quickly. The crab’s various leg varieties are crucial to its survival in that way.

There is still a lot to discover about the interesting critters known as crabs.

We may be aware that most crabs have ten legs, but they employ those legs for various things.

Take a closer look at a crab’s legs the next time you encounter one, and see if you can identify the differences.


Are Crabs Lobsters?

Crabs are not lobsters, though. Classification of crabs decapod crustaceans and are under the suborder Brachyura. True crabs can be recognized by their short tails and tiny, mainly under the thorax and abdomen.

Do Sea Crabs Jump?

Yes, sea crabs can jump. They can jump up to many feet in one jump and utilize their big claws to help them push themselves through the air. Although most kinds of crabs only jump when startled or threatened, several species will also leap to mate.

Also read: How Do Lobsters Communicate? +5 Incredible Facts About Lobsters


All crabs, regardless of species, have ten legs. In actuality, crabs belong to the group Decapoda, which can be interpreted as “decapod” to indicate “ten legs.”

From here, various crab species are broken down into multiple infra orders, although they all share the trait of being a decapod.

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