Crabs have hard shells and their juicy meat is a popular seafood.There are true crabs and then their relatives are lobsters. Crabs belong to the category of decapod crustaceans.The scientific name of true crabs is Brachyura which is also the name of the infraorder they belong to. Crabs can be found in both oceans and also in freshwater. Crabs live in water as well as on land. Yet, some species of crabs only live in water. The various species of crabs include hermit crabs, spider crabs, swimming crabs, fiddler crabs, red crabs, and king crabs. Squat lobsters are considered to be close relatives of hermit crabs.Crabs are believed to have been alive since the Jurassic Age. Interestingly, a group of crabs together is known as a cast. Crabs are also well known for their uniquely colored blood. These crustaceans have blue blood because of the amount of copper present in their blood. This feature of crabs makes them very different from other animals.How many claws do crabs have?Along with their shells, crabs also have claws. All crabs have two claws that are found towards the front of their bodies.The claws of crabs are useful to catch and hold things. Their claws are placed in a way that helps them to bring any prey they catch close to their mouths to eat. A crab claw cannot only catch but also chop or crush the body of the prey. This is why when you are picking up a crab, make sure that these appendages are out of the reach of your skin, or else they can pinch you hard.How many legs do crabs have?All crab species, including king crabs and hermit crabs, have five sets of paired legs. This means that a crab has 10 legs in total.However, sometimes not all the legs of these crustaceans are visible. Only eight legs, four on each side, are visible and these are known as walking legs as they help a crab to move from one place to another. The last pair of legs, in some cases, is hidden inside under the body while a crab walks on land.In some species, the last pair of legs are used to swim and paddle in the water. The very front pair of legs is what is known as crab claws.How do crabs walk? A crab uses three pairs of its legs to walk on land. However, crabs have a very different way of walking than most other species of animals.The jointed legs of crabs are designed in such a way that crabs walk sideways. Yet, while other crabs walk sideways, spider crabs can walk forwards and backwards. There are other crab species that can walk forwards and backwards too.Can crabs regrow their legs?You might wonder what happens when a crab loses one leg or more when it is so crucial for its movement? Well, they have a unique ability that can help in such situations.A crab has the ability to regenerate its limbs after a while. Similar to insects like a spider, a crab might break its leg at any weak point if it gets caught in something. The limb will grow back after some time. This is possible through the presence of regenerative genes in these organisms.Why do crabs have shells?The body of a crab is encased in a hard shell, which is accompanied by teeth or spines. Crabs are also covered with minute hairs, which are known as setae. These hairs are used to detect movement, touch, and chemicals in the surroundings of crabs. Crab shells act like protective shields that prevent attacks from predators. Like many other animals, their old shells fall off when a new soft shell develops under the previous one.During the period when the old shell is shed and the new shell is still soft and in the process of hardening, crabs are quite vulnerable. If predators try to attack a crab within this period, they would be successful. Shells of some crab species also act as camouflage to hide from predators. For instance, mud crabs have shells that are mud color. They borrow under mud to make themselves invisible to any approaching predators.Male crabs use the time when their shells are soft to fertilize eggs carried by female crabs. When mating is complete, the female carries the fertilized eggs until they are ready to hatch. The eggs are carried by a female crab under its abdominal flap. This abdominal flap also helps to differentiate between female and male crabs.The abdominal flap, which is also considered a tail, can be seen when you turn the crab over onto its back. While males have thin and narrow flaps, females have wide and more rounded flaps.Many crabs are omnivorous in nature, which means crabs eat both plants and meat. They are also scavengers, so they eat dead animals they find in their surroundings. On the other hand, crabs eat seaweed and other plants too. They can also hunt small animals to feed on.
Crabs have hard shells and their juicy meat is a popular seafood.
