Difference between crab and crab

Crab and crab are two terms used to name a type of crustacean. In this sense, for many people the main difference between these two terms lies in the habitat where these crustaceans live, since the crab is a freshwater crustacean and the crab is a saltwater crustacean.

However, there are other specific characteristics that make these crustaceans differ from each other, which we will point out below.


It can be said that the name of crab designates a decapod crustacean that has five pairs of legs and that its body is covered with a dark green exoskeleton. The decapods are an order of crustaceans within the class -malacostraca-, which has many family groups, such as crabs, spider crabs, lobsters and shrimp. These usually live in the mouths of rivers, between fresh and salt water, but for the most part they thrive in fresh water.

The scientific name of the crab is -Callinectes sapidus- and it is also known as blue crab. They feed on small crustaceans, fish, molluscs and algae. We can say that, as a differentiating physical characteristic, the males have gray-bluish legs, which is why they are called blue crab as well as blue crab.

On the other hand, the legs of the females have a reddish hue at the tips and since the crab belongs to the order of the decapods (crustaceans that have five pairs of legs) and that they are known as crabs, then it can be said that, the crab is a type of crab.


With the name of crab is designated the entire set of crustaceans of the order of the decapods, that is, crustaceans that have five pairs of legs together with lobsters, crabs, shrimps and prawns. However, colloquially it is called the group of decapods whose legs are aligned on each side in a parallel way. Likewise, as a differentiating characteristic, the front legs have evolved in such a way that they are a kind of larger pincers to the rear and side legs, which allows them to grab their prey and help cut it. This pincer also constitutes a defense mechanism against its predators and for the territorial dispute with other individuals of its species.

On the other hand, within the order of the decapods there is the superorder -Pleocyemata-, within which there are different species known as crabs, where we can find the king crab, the fiddler crab, the plush crab, the hermit crab and the stone crab. , among others.

Next, most of the crabs are saltwater crustaceans, although some species live on land near the sea, where they usually go to reproduce, and others live in the mouths of rivers, such as the crab. Since they are not very good swimmers, they move on the bottom of the sea with their large legs, mostly serrated, and they usually feed on small crustaceans, algae and fish.

As can be seen, the crab and the crabs have the common point that they are crustaceans that belong to the order of the decapods. However, the specific characteristic that differentiates the crab from the crab is referred to the habitat of each of them:

  • Crab is a freshwater decapod crustacean and crabs are saltwater decapod crustaceans.

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