Meet the American Lobster

Fast Facts

  • Common name: American Lobster
  • Scientific name: Homarus americanus
  • Size: Usually 8-24 inches (but can grow up to 3 feet!)
  • Lifespan: 60+ years

Geographic Range

The American lobster (Homarus americanus) is found along the coast of North America, ranging from Labrador, Canada to North Carolina. They are the most abundant in the New England area -- as much as 94% of the catch comes from the Gulf of Maine, which is why it’s sometimes called the Maine lobster.

Characteristics

The lobster has a hard exoskeleton, like an insect. Most of the time, lobsters are a natural muddy brown color when they’re alive and they turn bright red when cooked. But sometimes, they’re orange, white, yellow, or even blue! Learn more about lobster colors here. 

Lobsters can be right and left handed! This one is a righty--the dominant crusher claw is on it's right side.

The American lobster has ten legs -- eight of which are used for walking. The walking legs are covered in bristle like hairs which allow the lobster to taste what its walking on! The other two are claws used for eating and defense. Their claws are asymmetrical. The larger one is called the crusher claw and is used for pulverizing shells of their prey or fighting. The smaller claw is the shredder claw has a finer edge that’s better for tearing. Lobsters can actually be right and left handed, just like humans!  A lobster will start life with two of the same sized claws. During development, the claw that the lobster uses more frequently will develop into the dominant larger crusher claw and the less frequently used claw will become the shredder.

Lobsters have two long antennae, used mostly for feeling. Additionally they have shorter antennules (mini antennae), sensitive chemoreceptors which help the lobster find food, choose a mate, and decide whether or not to flee or fight.

Growth

Larval lobster

Lobsters start off life as tiny planktonic larvae that hatch from eggs carried by their mother and grow through molting (shedding their shell). American lobsters can grow to be quite large and have been recorded at lengths of three feet, weighing 40 pounds! Young lobsters molt frequently. By the time a lobster is between 5-7 years old,  it has molted about 25 times. As lobsters get older they molt less frequently and may only molt once every 1-2 years. Watching a lobster molt is pretty incredible. When a lobster molts, the shell splits between the tail and carapace and the lobster must pull its entire body out of the old shell. That means that even the large claws must first squeeze through the narrow knuckle (arm) area before molting is complete! Underneath the hard shell, the lobster has been growing a soft new shell, which it expands by pumping with water so that the lobster has room to grow. The new shell is very soft leaving the lobster extremely vulnerable to predation. Recently molted lobsters are sometimes called jellies and often hide in crevices while their new shell hardens. A lobster will also sometimes eat its old shell to help strengthen the new one.

Habitat

Lobsters live on the bottom of the ocean. They prefer rocky reef habitats where there are plenty of crevices and caves for them to hide in. However, they can also be found on sandy or muddy bottoms. Lobsters migrate seasonally. When waters are cold in the winter and early spring, most lobsters move offshore to deeper waters where the temperatures are actually warmer. In late spring and early summer, inshore waters begin to warm and lobsters migrate back to the coastal shallow waters where many molt.

Behavior

Lobsters are mostly nocturnal. They typically avoid predators such as cod, flounder, striped bass, sculpins, crabs, and seals by hiding in rocky caves during the day and emerging mostly at night to search for food. Lobsters are scavengers eating both dead and live prey. Their diet mostly consists of small fish, clams, crabs, mussels, algae, and eelgrass. In captivity they have been known to resort to cannibalism! Additionally, in the Gulf of Maine where lobster traps are prevalent, a significant part of a lobster’s diet consists of bait from the traps.

The American lobster tends to be a loner and prefers its own space. However, when living in more densely populated areas, lobsters actually develop a social hierarchy! Males will fight for the best den/cave and title of dominant male. The male who wins, not only gets the best home but also receives the most attention from all the local ladies.

Mating

It’s a known fact that lobsters fall in love and mate for life. You can actually see old lobster couples walkin’ around their tanks holding claws.
— Phoebe Buffay, Friends

The mating ritual of lobster is fairly complex and is not quite the love story that tv media has popularized. Lobsters do not mate for life (sorry Friends fans, Phoebe was wrong.) However, that’s not to say they aren’t romantic. Their relationships are short and sweet--the mating ritual involves courtship, knighting, undressing, stroking, fanning, and providing meals and protection.

The female lobster chooses her mate and seduces him with her pheromones.

In order to mate, a female lobster must first molt. Since this typically only happens about once a year, timing is everything. The female is actually the one who chooses her partner. Shortly before a female is ready to molt, she will visit the cave of the male she is interested in. This is typically the dominiant male in the area, since he has proven to have superior genes and most likely provides the best protection. She will continue to visit his den night after night indicating her interest. The courtship goes on until the female is ready to molt. Once ready, the female “knights” the male by placing her big claw on his head and she emits a pheromone which alerts the male that the time is right. Once she has undressed (molted), he waits patiently stroking her with his antennaes (how sweet) until she has hardened enough that he won’t tear her new shell. The mating itself is pretty quick. Afterwards the male will protect her while her new shell hardens. He will leave the den to bring back food and eventually she will be strong enough to go off on her own. They most likely will never see each other again.

The male is then ready for his next suitress. Females in an area will actually sync up their molt schedules so that they each get a turn mating with the dominant male. This is referred to as serial monogamy.

Female lobster with eggs.

The female will carry the sperm until she is ready to extrude her eggs. She then carries the fertilized eggs under her tail for 10 to 11 months before they hatch. The number of eggs the female has depends on how big she is -- the bigger the lobster, the more eggs she can lay -- it ranges from 3,000 to 75,000. That may sounds like a lot, but less than one percent of those eggs will survive the first month. Newly hatched lobsters are very vulnerable to predation. They float in the water column for about two weeks before settling on the seafloor. Once they reach adulthood, humans become their biggest predator!


Next step: We’ll introduce you to the lobster fishery next, so stay tuned!