Lobster Anatomy: Understanding The Basics Of Lobster Lingo

Parts-Lobster
Click to enlarge infographic.

Understanding the anatomy of a lobster is crucial for anyone interested in the biology of these fascinating crustaceans. Lobsters are known for their hard exoskeleton, which protects their soft internal organs. In this guide, you will learn about the different parts of a lobster’s body and how they function.

The External Anatomy of a Lobster

Maine Lobster Anatomy Dorsal View

Here is a little primer on the parts of the lobster so you know what you are cracking into! Speaking of eating lobster, learn how to crack and eat a whole lobster.

Shell: The shell is the lobster’s skeleton and cannot grow; it instead must be shed through a process called “molting.” Find out why molting is vital in buying an excellent hard-shell lobster.

Antennas: Lobsters have four long and thin antennas covered by tiny hairs, which allow them to smell.

Stalks: Lobsters have eyes on long, thin structures called stalks. Find out more about lobster’s compound eyes.

Lobster Anatomy Ventral View

Carapace: It is the armor-like body of the crustacean with the claws, knuckles, and tail removed. It houses the legs, the tomalley (see below), and, in the females, the roe (see below). In the State of Maine, legal lobsters are measured by shell length. Lobsters under 3 ¼ inches or over five inches must return to the water.

Legs: Lobsters have 10 legs. The four pairs of legs contain small strips of meat that take some work to remove. Lobsters use the eight back legs to walk. The front legs have claws called pincers.

Claws: Lobsters use their claws to catch food and battle predators and other lobsters. The larger of the two claws is called the crusher claw, and the smaller claw is called the pincer or cutter claw. The claws of hard-shell lobsters are full of tender, sweet meat.

Knuckles: The two joints connect the large claws to the carapace. Connoisseurs say the knuckle meat is the tastiest.

Tails: The tail holds the biggest piece of meat in the lobster.

The Internal Anatomy of a Lobster

Internal Anatomy Lobster

Digestive System: Lobsters have a three-part digestive system – foregut, midgut, and hindgut. The foregut breaks down food, the midgut absorbs nutrients, and the hindgut eliminates waste. They also have grinding teeth for breaking down hard-shelled prey.

Circulatory System: Lobsters have an open circulatory system, meaning their blood is not always contained within blood vessels. Instead, their blood flows through a series of sinuses and cavities. Lobsters have clear-colored blood that turns blue due to copper in their blood cells. Their circulatory system also includes a heart, which pumps blood throughout their body.

Nervous System: Lobsters have ganglia throughout their body, allowing them to react to stimuli and sense their surroundings. They also possess compound eyes and antennae to navigate their environment.

Respiratory System: Lobsters breathe through the gills in their abdomen. Water flows over the gills to extract oxygen. Swimmerets on their abdomen help move water over the gills.

Reproductive System: Male lobsters have a pair of reproductive organs called testes, while female lobsters have ovaries. During mating, the male transfers sperm to the female using specialized appendages called gonopods. Female lobsters carry fertilized eggs on their pleopods (swimmerets) until they hatch into larvae.

Lobster Sizing Names

  • Shorts or Snappers: A lobster under the legal size limit.
  • Canners: Small lobsters approximately 1/2 to 1 pound. They took their name in the 1880s because these size lobsters were “canned” and sold on shelves.
  • Market:  A size category for lobsters available for sale ranging from 1 to 3 pounds.
  • Chickens: A lobster weighing about 1 pound.
  • Culls: A lobster that has lost one or both claws. Generally sold at a lower price.
  • Quarters: A lobster weighing 1-1/4 pounds.
  • Selects: A lobster weighing from 1 ½ to 1 3/4 pounds. Buy select lobsters.
  • Deuces: A lobster weighing about 2 pounds. Buy deuces or 2 lb. lobsters.
  • Jumbos: A lobster weighing over 2-1/2 pounds. Order jumbo lobsters!

What Is the Best Part of the Lobster to Eat?

The tail is the most substantial part, while the claws are tender and succulent. The knuckles, legs, and body meat are also popular choices. Lobster is a healthy seafood, high in protein and low in fat. Enjoy a delicious and nutritious meal with any part of the lobster!

What’s the Stuff Inside Your Lobster?

Roe: The red stuff is the “coral” or tiny lobster eggs of the female lobster. It is found at the base of the body and along the tail. The roe is black uncooked, but the color can vary depending on the lobster’s diet. Lobster eggs were once considered a delicacy, like caviar.

White Stuff: The lobster blood looks like egg whites, uncooked and transparent. Try it in sauces.

Tomalley: The liver and pancreas are the light-green tomalley (hepatopancreas) in the lobster’s carapace. Although lobster lovers adore the rich as butter tomalley, it should be eaten sparingly. As with other animals, contaminants may settle in the liver, so it’s best to be safe.

Interested in ordering live lobster online, but unsure of what size to buy? Here are some tips on what size lobster to order.

Lobster Anatomy Quick FAQS

A Maine lobster has how many body parts?

A Maine lobster has 19 body parts!

What color is the lobster’s blood?

Lobster’s blood is colorless and, when exposed to oxygen, turns to a blue tint. The blue hue is due to the iron the lobster’s body uses to transport oxygen. Human red-colored blood is due to iron being the oxygen carrier.

When lobsters are cooked, the blood turns to a white, opaque color with a gel-like consistency. It is safe to eat.

What is the red stuff in the lobster?

The hard red substance is the roe or the eggs of the female lobster. It is also called coral because of its deep red color. The roe will be black and will appear gelatin-like if your lobster is undercooked. It is edible but can also be rinsed out.

What’s that Green Stuff in the lobster?

The green substance is the liver, also known as tomalley. It can be rinsed out of the cooked lobster.

Why is my lobster is missing a claw?

On occasion, a lobster will drop its claw as a defense mechanism. This can happen in shipping and the wild. Lobsters will battle other lobsters over territorial rites.

A lobster with only one claw is called a Cull and is often a good deal at the local lobster pound.
It can take several molts for a lobster to grow back its claw. Cooking your lobster with its dropped or broken-off claws is fine if it arrives alive.

What color is a Maine lobster?

The American lobsters are usually bluish-green to brown with red spines when uncooked. However, an estimated one in 2 million lobsters are blue. Lobsters only turn ‘red’ when cooked.

Comments

  1. This was fascinating information, thank you! And I enjoyed the humor. I bear no ill will to anyone who farms, fishes or eats lobster, but this all confirms that I could never eat one, although I’m sure they’re delicious. (For 40 years I was veg, then sadly, for health reasons, began to eat birds and fish.) Lobsters are just to amazing to eat. And remember the one that became a news story a few decades back? 150 years old and walked the ocean floor to the US East Coast from Asia! Incredible accomplishment! More than I’ve ever done. Couldn’t eat ’em.

    If you have time for a Q, can a lobster survive in the wild if it has lost both its claws? Can it even eat, if has only one? Seems like killing and eating would be a two-claw job. Anyway, thanks so much for the history and anatomy lesson!

      1. True, although it takes about 5 years for the new claw to get to the size of the one they previously had.
        As far as the original question, they are still technically able to eat somewhat using their pincers. The biggest risk to being clawless would be predators and other lobsters, but yes some do live without them.

  2. Since this is lobster lingo, the correct terminology is tomalley (from the Carib word tumale, meaning a sauce of lobster liver), not tamale, (from the Spanish word tamal, plural tamales, in Mesoamerican cuisine, a small steamed cake of dough made from corn).

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