Difference between Crab and Lobster

Crab and lobster both are marine invertebrates that belong to the class Crustacea under the phylum Arthropoda. Both are popular seafood. Although both are crustaceans and look alike, they do not have much in common. Let us see how a crab differs from a lobster!

Crab:

Crabs are marine invertebrates that belong to the class Crustacea under the phylum Arthropoda. There are around 6800 species of crab found in a wide range of habitats such as fresh water, marine water and terrestrial ecosystems. Accordingly, they are found all over the world but are abundant in tropical and subtropical geographical areas.

Their body is wide and is covered with large carapace, thick circular exoskeleton and eyes are located on the eyestalks. They have four pairs of legs and one pair of claws called chelae which they use to walk sideways. Their tails and antennae are very small. The female crabs have roundish abdomen, whereas the male crabs have triangular abdomen.

Crabs vary greatly in size, e.g. they can be as small as a few millimeters and can be as large as 13 feet. Their life span can be up to 13 years. They are omnivorous as they can feed on worms, algae, plankton, fungi, mollusks, small fishes etc. According to studies, they are cooperative creatures as they tend to work together to protect, feed and find shelter for their family. Furthermore, they undergo molting in which they shed their exoskeleton in order to grow.

Lobster:

Lobsters are marine invertebrates that belong to the class Crustacea under the phylum Arthropoda. There are around 85 species of lobster found all over the world particularly in oceans except for the Polar Regions. Their body is elongated, covered with an exoskeleton, and provided with muscular tail and long antennae. The eyes are present near the base of the antennae. They have 5 pairs of legs, with the first pair of legs modified into claws and larger than the rest.

Lobsters can dwell in saltwater, freshwater and land. Lobsters are physically larger than crabs as they can measure up to 20 inches long and can live up to 70 years. They walk slowly on the seafloor and swim by curling or uncurling their abdomen. They are omnivorous creatures as they can feed on worms, seaweeds, seashells, small fishes and other crustaceans. Furthermore, lobsters undergo molting to grow and also change their colour when they shed their shell.

Based on the above information, some of the key differences between crab and lobster are as follows: