Lobster vs Crayfish: How to Tell Them Apart

The most obvious difference between lobsters and crayfish is size. Lobsters are among the largest freshwater and marine crustaceans on Earth. A typical adult lobster weighs 1 to 5 pounds and measures 12 to 24 inches long from head to tail. Large lobsters can grow even bigger, reaching 3 feet in length and weighing 15 pounds or more. Crayfish are tiny compared to lobsters. An average crayfish measures only 2 to 6 inches long from head to tail. A crayfish typically weighs less than an ounce to just a few ounces. This enormous size difference is the fastest way to tell them apart. If you catch a small crustacean that looks like a tiny lobster in a freshwater stream or pond, it is definitely a crayfish. If you see a large crustacean in saltwater, it is almost certainly a lobster. The size difference reflects their different lifestyles and environments. Learn more at /wildlife.

Lobsters and crayfish live in completely different environments. Lobsters are marine animals that spend their entire lives in the ocean. American lobsters live in the Atlantic Ocean along the eastern coast of North America. They prefer cold saltwater depths, usually staying on or near the ocean floor. Lobsters are found from the shallow coastal waters to depths of hundreds of feet. They cannot survive in freshwater and will die if placed in lakes or rivers. Crayfish, by contrast, are freshwater animals found across North America. Different crayfish species live in different freshwater environments. Some crayfish prefer rocky streams with fast-moving water. Others live in swamps, marshes, or slow rivers. Many crayfish species live in ponds and lakes. A few species are found in cave systems with underground water. Crayfish are completely adapted to freshwater life and cannot survive in saltwater. If you are looking at an animal in the ocean, you are seeing a lobster. Visit /wildlife to learn more about freshwater and marine habitats.

Lobsters and crayfish have very similar body shapes because they are distant cousins in the crustacean family. Both have a head region with eyes on stalks, a thorax section, and a segmented tail. Both have ten legs, with the front two modified into claws. Despite these similarities, several differences stand out. Lobster claws are much larger and stronger than crayfish claws. A lobster's front two claws, called chelipeds, are massive and powerful. These claws can snap with tremendous force and inflict serious injury. Crayfish claws are proportionally much smaller and weaker. A crayfish claw is delicate and used mainly for handling food, not for fighting or crushing prey. The lobster's entire body is also heavier and more strong. Lobster shells are thicker and harder. Crayfish have thinner, more delicate shells. The lobster's tail is thick and muscular, containing substantial edible meat. A crayfish tail is thinner and contains much less meat. You can see these differences if you examine the animals closely at /wildlife.

Lobsters and crayfish are both omnivores that eat dead animals and plant material on the bottom of their habitats. They are scavengers that use their claws and legs to manipulate food and move it toward their mouths. Lobsters are ambush hunters that will also actively hunt live prey. A lobster will grab small fish, other crustaceans, or mollusks. Lobsters use their large claws to crush hard-shelled prey. They can crush the shells of sea urchins, clams, and mussels. Crayfish also eat other small animals and plants. They will eat small fish eggs, insects, and dead fish. Crayfish use their smaller claws to tear apart food items. A crayfish cannot crush hard shells like a lobster can. Both animals are most active at night, when they emerge to hunt and scavenge. During the day, both tend to hide under rocks or in crevices to avoid predators. Their similar hunting strategies reflect their common ancestry, even though they live in different water types. Find /wildlife for more details.

Lobsters and crayfish come in different colors depending on species and environment. Most American lobsters are dark brown or greenish-brown. Some lobsters display reddish or yellowish tones. When lobsters are cooked, their shells turn bright red due to a chemical change in pigments. Lobster shells are thick and somewhat rough-textured. Crayfish display much more color variation. Many crayfish species are brown or tan, which helps them blend into muddy streambeds. Other crayfish species are distinctly red or reddish-brown. Some North American crayfish species are blue or blue-gray in color. A few rare species are bright orange or even white. Crayfish shells are smoother and more delicate-looking than lobster shells. Young lobsters are sometimes confused with large crayfish, but the size difference usually makes them easy to separate. A baby lobster is still larger than most adult crayfish. Lobsters and crayfish also have different eye arrangements. Both have eyes on stalks, but a lobster's eye stalks are larger and more prominent than a crayfish's eye stalks. Learn more at /wildlife.

Many people confuse lobsters and crayfish or think they are closely related. While both are crustaceans, they are not directly related like siblings. They belong to different families within the crustacean group. Lobsters belong to the family Nephropidae, the true lobsters. Crayfish belong to the family Astacidae or Cambaridae, depending on species. One confusion is that crayfish are sometimes called crawfish or crawdads, making people think they are different animals. Crawfish and crawdad are simply regional names for crayfish, not different species. Another myth is that crayfish are baby lobsters. This is false. A baby lobster is called a lobsterling and is much larger than an adult crayfish. Crayfish and lobsters hatch from eggs but follow completely different growth paths. A third confusion involves cooking. Some people think crayfish and lobster meat taste the same. Lobster meat is typically sweeter and more tender. Crayfish meat is slightly different in flavor and texture. Both are edible and considered delicacies in many places. However, they are definitely not the same animal.