The Life of a Lobster: Clawed Lobsters, Crayfish, and Lobster Imposters

Between lobsters the color of cotton candy, depressed lobster men, and misinformation spread by the wonderful Phoebe from Friends, there is a lot to learn about lobsters. Let’s dive in.

What to Expect in this Article

  1. What Kind of Animals are Lobsters and Crayfish?
  2. Lobsters Anatomy and WTF is a Crayfish?
  3. Lobsters Don’t Mate for Life
  4. Depressed Lobsters
  5. The True Lobsters: Strong Claws and Cotton Candy
  6. The Spiny Lobster: Screeching for Defense
  7. Slipper Lobsters: Plates instead of Antennas
  8. Furry Lobsters: Hair on a Shell?!
  9. What’s Next?

What Kind of Animals are Lobsters and Crayfish?

First of all: obviously crayfish aren’t fish. Duh. So, what are they?

Lobsters and crayfish are crustaceans, closely related to the cute little shrimp we talked about last time.

To get from the crustaceans to the lobsters and crayfish, we follow pretty much the same path as we did to reach the shrimp. Multicrustacea, Malacostraca, Eumalacostraca, Eucarida, Decapoda, Pleocyemata. Instead of taking a turn toward the Caridea, the true shrimp, we instead climb on to the Astacidae, the true lobsters and crayfish.

Crustacean Tree of Life designed by Kate Hildenbrand based on the NCBI database

Within the Astacidea, there are four groups: two groups of crayfish and two groups of lobsters. The Astacoidea and Parastacoidea both contain crayfish species, while the Nephroidea and Enoplometopoidea both contain lobsters.

In addition to these true lobsters, there are creatures we call lobsters in the Achelata, a sister taxon to the Astacidea. These imposter lobsters include the spiny lobsters, the slipper lobsters, and something cutely called the furry lobsters.

Lobster Anatomy and WTF is a Crayfish?

The difference between lobsters and crayfish is rather simple: lobsters, no matter if true or imposter, are marine species, while crayfish are freshwater species.

It’s also not hard to distinguish the true lobsters from the rest of the wanna-be lobsters: true lobsters are also called clawed lobsters—and for good reason.

But before we get into the chelipeds, the clawed feet, let’s have a brief look at the anatomy of lobsters and crayfish:

Their bodies are divided into the cephalothorax, so the part that has the head (cephalo-) and the chest (-thorax), the abdomen which people often call the tail, and the telson, the actual tail. On either side are five pairs of legs. A pair of chelipeds, and four pairs of walking legs or pereiopods.

Their heads sport antennules which are essentially the nose, an actual pair of antennae for touch, and the rostrum with the eyes.

On the other end the central tail fin or telson holds the uropods, the outer tail “legs” which obviously don’t actually count as legs because they are more like fins. If they counted, the decapods would need a renaming.

Okay, back to the difference between lobsters, imposter lobsters, and crayfish: crayfish and true lobsters have large claws at the end of their first pair of legs. All the fake lobsters are lacking these and instead use their mandibles (jaws) to crush their food.

The claws of crayfish are symmetrical, so the right and left chelae are the same size and shape—and they use both equally. Researchers did some not so nice things to crayfish to find out that they don’t have a preference here. This is where we leave the freshwater lobsters behind, and focus on the marine species. Marine ecologist and all that.

Other than their freshwater relatives, clawed lobsters do have a dominant, larger claw, and a more agile smaller claw. And just like with humans, there are right-handed, I mean right-clawed, and left-clawed lobsters. More not so nice things were done to lobsters to find out when this preference is decided, and the researchers found that the symmetry is decided at some point after hatching but before adult-hood.

Lobsters Don’t Mate for Life

Speaking of life stages: Remember that scene in Friends where Phoebe tells Ross that Rachel is his lobster. “It’s a known fact that lobsters fall in love and mate for life.” But lobsters might be much more like Barney from the early seasons of How I Met your Mother.

Especially male lobsters are rather promiscuous. They are monogamous for about two weeks at a time. So, typically, they aren’t cheaters, but they do break up rather quickly after mating. A study by Elisa Karnofsky and Holly Price described the females as “fickle.” They would move in with one male, but then change their mind and switch to another. Once decided, the female typically moves in within the week before molting—a highly vulnerable time for her. Within half an hour of molting, they duck, and then she takes over the responsibility for the eggs while dad moves on to the next female or single life.

It takes six to nine months for the eggs to appear on her abdomen. The female then carries the eggs until they are ready to hatch. And it’s a serious pregnancy of six to nine months. There are quite a few eggs in every batch. Just look at the underside of a berried—egg-carrying—lobster, and you’ll get an idea of the sheer mass of eggs in each batch. Thousands! Tens of thousands. And chances are, one of ’em will make it. Nature is cruel. But that’s how evolution works fastest, so it’s probably a good thing.

The tiny larvae have a leg-up on shrimp because they spend a bit longer inside their egg—and thus cared for and protected by mom—before they hatch. The tiny baby lobsters (or crayfish, for that matter) then join the planktonic community until they have molted a couple of times and sink to the bottom as miniature lobsters. There, they grow and molt a few more times into first adolescents and then mature adults. This whole process takes years, and even then, females can usually only spawn every other year for her early adulthood. Later, they get around to ducking every successive year instead.

Lobsters, real or imposter, mature between five and eight years of age. Even if they only reproduce every other year, that’s a lot of chances for a lot of offspring—especially when there are thousands in a batch. Spiny lobsters can reach thirty to fifty years—quite an age! True lobsters—the ones with the claws—can get even older. But no, it’s not true that they are immortal. It’s just that they have an enzyme called telomerase that extends the life of cells. Humans have that stuff, too, but most of our cells don’t have any activity of that miracle stuff. It’s in our embryonic tissue and stem cells, but that’s just about it. So, lobsters, are a tiny bit more immortal than humans—in one specific way. Definitely not immortal.

Depressed Lobsters

It’s not the only characteristics shared by lobsters and humans, by the way. Male lobsters have a one-track mind. No, not like that. They want to fight. And as we learned that females can be quite fickle when it comes to choosing a mate, this is no surprise. If there are no other males near the den, females are less likely to run off with another dude.

After losing a fight, lobsters become essentially depressed. Human anti-depressants actually revive the willingness to fight. Yep, lobsters have a similar enough system that giving them serotonin works very similarly to the way it does in our brains.

Honestly, though, I’d be more depressed about getting fished to extinction by humans. In 2016, 59,000 tonnes of Maine lobster alone were taken out of the ocean for human consumption. That’s $533 million worth of lobster.

But before my mood get as blue as the lobster’s blood, let’s return to our amazing critters:

The True Lobsters: Strong Claws and Cotton Candy

The true or clawed lobsters, the Nephropidae, are the real deal. More closely related to crayfish than to spiny, slipper, or furry lobsters, they are the only lobsters that deserve the name.

While most lobsters are brown or green, there are pretty amazing colors out there. From rare two-toned ones to even rarer cotton-candy variants of the albino mutation, some lobsters are definitely far from boring brown or gray. Oh, and to make them even cooler, the split-colored ones are hermaphroditic, too. It’s a miracle to me how humans can think LGBTQ+ is unnatural. Seriously!

But what is coolest about the clawed lobster is, well, their claws. They are ducking strong. As they need to break open shelled organisms like mussels, crabs, or other lobsters, they need to be crushingly strong. Their claws can pinch with almost seven bar of strength. For those of you who understand weird units, that’s about a hundred pounds per square inch. Pounds per square inch? Ah, gotta love American units. Anyway, they are forceful, and excellently adapted to their prey.

And, as their muscles work differently from ours, they don’t even need a lot of energy to pinch, pinch, pinch.

Oh, and if they lose a claw, they can regrow another one. Takes a while, but it’s still ducking impressive that lobsters (true and imposter) can regrow limbs, let alone those giant claw weapons.

The Spiny Lobster: Screeching for Defense

Spiny lobsters or rock lobsters are my favorite group of imposter lobsters. What they lack in claws, they make up for in—I don’t know. I just really enjoyed finding them in rock crevices on our California dives. Cod, I miss California more than I care to admit.

California Spiny Lobster (Panulirus interruptus) photographed by Kate Hildenbrand.

Anyway, spiny lobster can be found in warmer waters than true lobsters. They even inhabit tropical and subtropical regions. So, while the true lobster migrates further and further North to get the right conditions for their eggs to hatch, the spiny lobster is better suited to slightly warmer temperatures—though they, too, have a limit and preference, of course. When it gets too hot, they can’t think properly and their perception of chemical signals is ducked up.

Except for some anatomical differences, spiny lobsters are a lot like true lobsters—very successful imposters, indeed. Though, I’m still not sure those small spines that are supposed to protect them really make up for the fancy claws of the true crabs.

Speaking of weird defenses: spiny lobsters have a unique sound effect. They can squeak or rasp with their mandibles and a kind of file. It isn’t 100% clear how all of this works yet, but researchers found that they make that sound when attacked by a predator, not before, so we think it startles predators.

I guess it’s a good thing they can regrow limbs… Those don’t sound too effective to me. But it seems to work for them.

Slipper Lobsters: Plates instead of Antennas

Slipper lobsters might just be the cutest thing I’ve ever seen: where they should have spindly antennae, they have enlarged antennae that are essentially wide plates. As they are used for stirring when in motion, rudder might be the better description. So, these stupidly cute things have rudders in their face.

I get why people call them shovel-nose lobsters.

They vary in size from an adorable 5.5 centimeters (2.2 inches) to half a meter (20 inches). Unsurprisingly, the smallest species is the pygmy slipper lobster, Scyllarus pygmaeus. The largest is the humpback slipper lobster. I know the name likely has nothing to do with humback whales, but it still makes it easy to remember that the largest slipper lobster is the humpback, Scyllarides haanii.

No matter their size, these shovel-nosed cuties like to stay grounded—much like their relatives. They are bottom-dwellers and nocturnal. As they can be found at depths of up to 800 meters (half a mile), they spend quite a bit of time in the dark. Thus, their eyes are super-well adapted to the dark. They have highly developed monochromatic eyes. So, no color, but excellent night vision.

Furry Lobsters: Hair on a Shell?!

There are only two extant, so living, species of furry lobsters. And very little information can be found about them anywhere online. From research papers to Wikipedia, very little seems to be out there.

But lobsters with fur are way too cute to ignore, so here’s what I found: They can be found in the Pacific Ocean in quite a few areas. However, apparently, they are too smart for lobster traps, so they are rarely used as a food source. Needing a diver to catch them with their hands or a spear is kinda discouraging for commercial interests. Smart little furry fellas.

They, too, can use sound for defense, and loudly screech their predators into a retreat. I keep thinking this can’t work but then I remember children screaming at the top of their lungs, and I wanna run just thinking about the sound.

The “fur,” by the way, is actually short hairs on the carapace, so the shell. I tried to figure out how that happened or what purpose hair on a nerve-less shell serves, but have to come up empty, unfortunately. I have some hypothesis, but nothing cooked enough to share. What do you think?

What’s Next?

Of course, humans are having a significant effect on the populations of lobsters (and crayfish, for that matter) worldwide. We’re changing the size of lobsters by taking the largest males, speeding up the climate-change-induced migration of lobsters toward cooler waters, and, well, take out tons and tons of the ten-legged creatures as food.

But, as this is the Climbing the Tree of Life series, we won’t go into any of that. Instead, may I suggest learning about shrimp in this article or about why we don’t just give up on saving nature in this one.



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