Difference Between Crab and Lobster


Main Difference

The main difference between the crab and lobster is the shape of their exoskeleton. The crab has a smaller circular exoskeleton, and the lobster is larger and longer.

Crab vs. Lobster

Crab and lobster are the marine invertebrates belonging to the group of crustaceans. Crabs belong to infraorder Brachyura family. Lobsters belong to the Nephropidae or Homaridae families. There are around 6800 species of crab that inhabit terrestrial ecosystems and fresh and marine water. They can be found all over the world but especially abundant in subtropical and tropical areas. Lobsters are the less diverse group of animals that are found around the world. There are about 48 species of lobster found in the oceans (and occasionally brackish water) except in the polar regions. Lobster spend life on the sandy, rocky or muddy seafloor, usually on the edge of the continental shelf or near the coast. Crabs can be so small (smaller than an inch in diameter) or so large (leg span of 13 feet). Lobsters are larger than crabs. They are 10 to 20 inches long, but some species can reach 3.25 feet in length and 44 pounds of weight. The crab has a smaller circular exoskeleton. The lobster is larger and longer with a long tail which consists of most of its meat. Crabs also have a distinctive walk, and they tend to walk sideways. Lobsters move forwards and backward and also have larger claws as compared to crabs. Crabs have a thick exoskeleton, round (females) or triangular-shaped (males) abdomen, four pairs of legs and one pair of claws called chelae. Their eyes are located on the long eyestalks. Lobsters have an elongated body covered with a light-weight exoskeleton. They have five pairs of legs.


Comparison Chart

Decapod crustaceans that belong to the infraorder BrachyuraMarine invertebrate that belongs to the Homaridae or Nephropidae families
Smaller with smaller tongs and fewer legsLarger with larger tongs and more legs
SidewaysForwards and backward
6,793 speciesMore than 500 species
Life span
8 to 13 yearsAround 70 years

What is Crab?

Crab is the decapod crustaceans that belong to the infraorder Brachyura. Crabs are covered with a thick exoskeleton. It has a single pair of claws. Crabs are found all over the world. They are a prime form of seafood in most cultures. Crabs live in fresh water and on land, mainly in tropical regions. Crabs form about 93 families under the Brachyura and consists of about 6,793 different species. Its body is wide, and eyestalks hold eyes. Its tail and antennae are small and are almost unnoticeable. Crab has a pair of chelae or claws, and uneven legs which it uses to walk sideways. Male crabs mainly have larger chelae and a narrow pleon, or abdomen. Female crabs have smaller claws and around the abdomen to store their eggs. Crab provides delicious, juicy meat and is typically abundant in warm areas. Crabs can be so small as a few millimeters and so large as 13 feet. Their life span is up to thirteen years. Crab is the omnivorous crustaceans. The food of crab is algae, plankton, small fish, worms, fungi, mollusks, and even other crustaceans. The main feature of crabs is a large carapace that covers them. Their tail is hidden ventrally underneath the body. According to research, the crabs are cooperative creatures that work together to protect, feed, and find shelter for their families. However, they are also hostile towards each other. Male crabs fight other males to find their mating partner and hiding holes. Crabs can survive 8 to 13 years.


What is Lobster?

Lobster is a marine invertebrate that belongs to the Homaridae or Nephropidae families. It is a large crustacean with muscular tails, elongated bodies, and long antennae. Lobsters have five pairs of their walking legs, with the first pair larger than the rest. They are up to twenty inches long. Lobsters are omnivorous creatures that primarily eat worms, seashells, fish, seaweeds, and other crustaceans. They like to live alone in rocky, muddy crevices on the sea floor or in burrows. Lobsters have a long, muscular tail with fan-shaped tip and very long antennas that function as sensory organs in the murky waters. Lobsters are invertebrates with a hard protective exoskeleton made of chitin. Since they are arthropods, lobsters molt their exoskeleton to grow, shed their shell, and also change their color. They walk slowly using their legs, but they can swim backward quickly. Lobsters can survive for around 70 years. They have ten walking legs. The front three pairs have claws and the first of which is the largest. Lobsters have antennas on the top of their head that they use as sensors in the water and to communicate. Research suggests that lobsters may not slow down, weaken, or lose fertility with age, and instead, older lobsters may be more fertile than younger lobsters. They have an efficient sensory system with antennae and antennules. Lobster are mainly omnivorous in feeding habits and eat both phytoplankton and zooplankton. Lobster is famous for their delicious meat and is considered a delicacy in some countries. It is a highly priced food both as raw meat and as cooked food.

Key Difference

  1. Crabs belong to infraorder Brachyura family whereas lobsters belong to the Nephropidae or Homaridae families.
  2. Crabs are less expensive as food. Conversely, lobsters are highly expensive and more delicious in taste.
  3. Crabs live in seawater, freshwater, and semi-aquatic conditions n the flip side lobsters are found in the ocean.
  4. The exoskeleton of crab is smaller and circular exoskeleton while the lobster has a larger and longer exoskeleton.
  5. Crabs usually walk sideways, on the other hand; lobsters move forwards and backward.
  6. Crabs can live up to thirteen years, and lobsters have a longer life span of about seventy years.


Crabs and lobsters are the marine invertebrates belonging to the group of crustaceans. Both are different in their size, shape, structure, and organs. Both are eaten as food around the world but have a distinct taste from each other.

Aimie Carlson

Aimie Carlson is an English language enthusiast who loves writing and has a master degree in English literature. Follow her on Twitter at @AimieCarlson