Lobster

Lobsters are a family of crustaceans that live in waters along most of the world’s coastlines. There are 30 known species of clawed lobsters and 45 species of spiny (or rock) lobsters. 

The largest lobster species is the American lobster, which can be found from the coasts of North Carolina to Newfoundland. Because American lobsters grow continuously throughout their lives, they can reach sizes larger than any other living crustacean.

Lobsters are arthropods, like insects and spiders, and share features such as an exoskeleton and jointed legs, but they are more closely related to other crustaceans. They’re omnivores, eating both fish and algae. Lobsters have poor eyesight, so they depend on their ability to taste and smell while moving across the bottom of the ocean.

5 Incredible Facts

• With a brain in their throat and teeth in their stomach, lobsters have some of the most unusual anatomy across the animal kingdom. Their eyes detect shadows and light, but not colors or images. Their stomach contains their “teeth,” a gastric mill that crushes up food. A lobster’s brain is located in its throat and is about the size of a grasshopper’s. Their heart and central nervous system lie in their abdomen. In addition, lobsters “taste” with their feet and “hear” using a series of sensory hairs on their legs!
• A lobster’s underbelly is as strong as car tires. The underbelly membrane of lobsters (which protects against rocks on the seafloor) is about as strong as industrial rubber.
• The largest lobster ever recorded might have been 100 years old. The largest lobster ever recorded was caught off Nova Scotia in 1977 and weighed 44 pounds 6 ounces, according to the Guinness Book of World Records. While age estimates of lobsters are inaccurate, it is believed this lobster may have been 100 years old.
• Lobsters used to be considered “cockroaches of the sea.” In the early 1800s, lobsters were so plentiful in New England that they occasionally would wash ashore in piles two feet high. While lobsters are now seen as “gourmet” food, they were so plentiful in early America that Massachusetts servants demanded no more than three dinners per week.
• The key to eternal life? Unlike most animals, which stop growing once they reach adulthood, lobsters continue to grow throughout their lives. Does this mean lobsters could hold the key to “immortal life?”

Classification and Scientific Name

In regards to the type of lobster most Americans know, its common name is the American or Maine lobster. Its scientific name is Homarus americanus. Other commonly used names include the Atlantic lobster as well as the true lobster.

Scientists think that decapods, like the mole crab (Emerita), evolved 450 million years ago, lobster-like crustaceans about 360 million years ago, and the ancestor of what we know today as the lobster showed up about 12 million years ago. Lobsters and crabs, then, share an evolutionary history.

The taxonomy of the lobster shows that it belongs to the Nephropidae family and is in the class Malacostraca, order Decapoda. The Greek word deka, meaning ten, and pous, meaning feet.

Other crustaceans, like spiny lobsters (Palinuridae) and slipper lobsters, may be called “lobster,” but they are not closely related and have no large claws like the very large front claws of the Maine lobster. The same is true for the squat lobster.

The relatives that are most similar are the reef lobsters and three families of freshwater crayfish. The term “lobster” is used for several groups of crustaceans, but only members of the family Nephropidae, such as the American or Maine lobster, are considered “true lobsters.”

Among edible lobsters, the Norway lobster (Nephrops norvegicus) is commercially popular in Europe, but it grows to only about 10 inches long. The average American lobster is twice that size.

Appearance and Behavior

When you think of a lobster, you may picture a red lobster sitting on someone’s dinner plate. However, they don’t turn red until after they’re cooked. The American or Maine lobster is greenish brown in color. Lobsters can be found in different colors, but these variations are extremely rare. The Maine Fishermen’s Alliance estimates that:

• Every one in two million lobsters is blue
• Looking for a yellow lobster? They’re seen once every 30 million lobsters.
• White lobsters are even rarer. The chance of seeing a white lobster is about one in 100 million.

The brownish color of most lobsters allows them to blend in with the sand and rocks on the bottom of the ocean. This can keep them hidden from predators. If a lobster spots a predator, it will scoot backward using its tail fin to move into a rock crevice. The fastest speed on record for a lobster moving backward is 11 mph. 

A lobster’s body has two main parts covered in a hard shell. It can grow to be a little more than three feet long, but the average is 8-24 inches. Lobsters vary in weight from 1 pound to 15 pounds. Of course, some lobsters weigh more than 15 pounds.

The American lobster has two claws, antennae, and two tiny black eyes. Its eyes don’t play a big part in its nocturnal hunting activities. The small sensory hairs on its ten legs and feet help a lobster to identify its prey. Also, a lobster uses its antennae to smell prey even if it’s far away.

Lobsters are solitary and shy animals most of the time. However, they become aggressive when defending their territory against other lobsters. One lobster may push another with its claws in an effort to move it out of the territory.

Habitat

American lobsters live in the northern Atlantic Ocean. They prefer cold water habitats and live on the floor of the ocean, hiding between rocks and digging in the sand. Different lobster subspecies, such as the Spiny lobster, live in warm, tropical waters like the Gulf of Mexico, the Caribbean Sea, and off the coast of Florida in the Atlantic Ocean.

The tiny eyes of a lobster have thousands of lenses. Their eyes are sensitive to bright light, so it’s a good thing they live at the bottom of the ocean. Although they can’t see clearly, lobsters can see shadows and dim images, which helps them avoid predators moving into the area. 

These crustaceans use both of their claws to dig into the sand near a rock to make themselves a home. This home can serve as protection against predators.

Scientists have found that American lobsters migrate away from the shoreline in the winter and spring. They want to live in the warmer, deep water during the cold weather months. As the weather warms up in the summer and stays warm into early fall, they move back toward the shore. Some lobsters move up and down the shoreline, never staying in one place. 

Diet

What do lobsters eat? Lobsters are omnivores. They eat mussels, sand fleas, clams, shrimp, and sometimes tiny fish. They are slow-moving, so they usually hunt slow-moving prey. They grab hold of their prey with their strong claws and squeeze. If they can’t find any of these animals to eat, lobsters eat plants that grow underwater.

Predators and Threats

Lobsters have many predators, including eels, crabs, seals, and rock gunnels. An eel is able to push its thin body into rock crevices to grab a lobster that’s hiding there. Seals are fast swimmers and can catch lobsters with their powerful jaws. In addition, some fish, such as flounder and cod, also eat lobsters. However, the biggest threat to lobsters is humans. Millions of lobsters are caught in nets to sell in seafood markets and restaurants. People eat the heavily muscled abdomen and claws of the American lobster, but only the abdomen (marketed as a lobster tail) of the spiny lobster.

When it comes to disease, lobsters can suffer from shell disease as well as different types of fungus and parasites. They are also threatened by chemicals and other pollutants in the ocean waters. The official conservation status of lobsters is Least Concern. 

Reproduction, Babies, and Lifespan

Lobster mating involves a dominant male that typically mates with a group of females. A unique aspect of lobster mating is that females must shed their hard outer shell before mating, which leaves them at risk of predation. During this period, females will live inside caves inhabited by males, who offer protection. After approximately two weeks, the female’s shell will have regrown, and she can leave. At this point, a new female will join the male.

A female lobster carries sperm from a male so she can fertilize her eggs in July or August. She carries her eggs on the underside of her abdomen for about ten months. The typical lobster carries 8,000 eggs at a time. However, some female lobsters can carry as many as 100,000 eggs. After ten months, the female releases the lobster larvae, also known as hatchlings, into the ocean waters. A female lobster breeds every two years.

For four to six weeks, the larvae float on or near the surface and eat plankton. During these weeks, the larvae molt (shed their shells) four times, growing a new one each time. After shedding its fourth shell, the larvae are large enough to sink to the ocean floor. 

Not surprisingly, it’s estimated that less than one percent of lobster larvae survive to sink to the ocean floor. These tiny larvae are eaten by fish, seals, sea gulls, and other animals before they’re large enough to settle. For example, fewer than 80 out of 8,000 larvae may survive to this stage.

Once a young lobster descends to the ocean floor, it makes its home by digging in the sand beneath a rock. At this point, the young lobster is very small, weighing only a fraction of a gram.

Lobsters can live to be 50 years old or older. As they age, they can suffer from shell rot and various types of parasites. The oldest lobster in the world was caught in 2009. Scientists believe it’s 140 years old.

Lobsters have the ability to regrow legs, claws, and antennae if they fall off due to injury or disease. In fact, scientists believe that losing a claw or leg is not a painful experience for a lobster. It can be lifesaving and prevent infection in the crustacean. This regrowth makes it a little easier to see how a lobster can live such a long life in the ocean.

Population

The population of American lobsters in the Gulf of Maine is approximately 250 million. Although millions of lobsters are caught each year by fishermen, the population is holding steady. The total population of spiny lobsters and other species that live in tropical waters is not known. The official conservation status of American lobsters is Least Concern.

As a note, if a fisherman catches a female lobster who is carrying eggs on her abdomen, it’s against the law to keep her. The fisherman must put her back in the water. This is one of the efforts being made to make sure the lobster population steadily grows.