If you don’t know what a lobster is already, they are large crayfish-like creatures that live exclusively in saltwater. A lobster’s defining feature is its large front claws and its dark red color. They are ancient creatures with many interesting abilities, some of which I will look into in this post!
Perhaps the most interesting fact about lobsters is that if a claw, antenna or leg is lost during a fight, the lobster will grow a fresh one in its place. Lobsters can regrow most of their limbs but it can take a few years for the entire process to complete.
However, they cannot regenerate complex appendages like their eyes or entire tails if they happen to lose them.
Lobsters can regrow most of their limbs including their claws if necessary. But this process is tightly coupled to its molting process. This can be a painful, time consuming and stressful process for lobsters since their shells and exoskeletons are necessary to maintain the health of their innards.
The lobster’s growth biology revolves around a constant cycle of renewal and regeneration fostered by their molting process where they outgrow their old shell and replace it with a new one. This is also the process they use to regrow their lost limbs!
Whereas lizards or fish rely on softer, slippery scales that do not offer the same level of protection, all crustaceans have a hard shell that they rely on to protect their organs but it does come with the trade-off that it makes it harder to grow.
Growth in lobsters is a complicated process because all bodily expansion or replacements in crustaceans like lobsters and crabs has to be coordinated with the growth of an entirely new outer shell!
In this post, we will discuss the full process of how lobsters regenerate limbs, and how often they do so, by looking at full cycle of this renewal process and the factors that play a role in speed and nature of the process.
Can Lobsters Regrow their Claws?
Yes. Lobsters can replace their claws when lost. The entire process can take up to two years, depending on how badly the claw is damaged.
The claws can reach different sizes, depending on whether the lobster is young or old, male or female.
Claws will often be lost through various types of fights or other lobster activity.
The lobster will only regrow a damaged claw if it is entirely removed from the body. If a claw is not lost entirely, the chances of regeneration decrease significantly as the body does not perceive the damage – therefore lobsters will often cut of their own claws if damaged!
Lobster claws are used for all manner of activities such as acquiring food, fighting, establishing and securing territory and for mating activities. It should be clear then, how evolution has made sure that any lobster, which happens to lose a claw in the wild, can regrow it again.
How Do Lobsters Regenerate Lost Limbs?
Like most crustaceans, lobsters are capable of regenerating lost appendages. Lobsters possess a number of abilities that facilitate this regenerative capacity.
When a limb is lost, the wound triggers a physiological response in the lobster that serves as an intrinsic reminder of the injury and a signal for regeneration!
They form scar tissue, which is initially fibrotic in nature, but as the lobster heals, new blood vessels and neurons grows with this fibrotic tissue and gives way to the regeneration of new functional limbs.
Lobsters are able to regenerate lost limbs and appendages through a process of molting. During this process, the lobster sheds its old exoskeleton and grows a new one.
This new exoskeleton is larger than the previous one, allowing the lobster to grow in size. The shed exoskeleton can also be used by other animals as a source of food or shelter.
Lobsters can regenerate appendages with considerable precision. Better than for example a lizard can regenerate its tail, where bones are replaced with cartilage and therefore the new tail is not as functional.
However, a lobster’s regenerated limb will not be an exact duplicate of the lost limb, but rather a regenerated limb that is smaller, larger, and has a different number of segments than the original.
How long does it take for a lobster to regrow a claw?
Lobsters take from a one to a few years to regrow new claws to their original size.
When a lobster loses a claw it takes multiple molts to grow a replacement. The lobster grows out smaller claws first which grow larger with each successive molt.
The time it takes the lobster to go through these molts that grow the new limbs depends entirely on the species, gender and age. Smaller lobsters grow claws faster than larger ones and males grow faster than females.
If the lobster is a juvenile, it will not require as much time to grow a new claw as a larger and older lobster, which only once per year on average.
It typically takes just a few molts for smaller, younger lobsters to grow a claw to near full size.
Commonly a young lobster may molt several times a year so it will take just a few months before a young lobster starts to grow its claw back and maximally two to three years before it reaches its original size (or bigger, as the lobster is also growing as a whole!).
With the slower molting schedule of the larger and older lobster, it may take a few years before the adult lobster has renovated claws. But considering that lobsters reach their adult age by 4-8 years (depending on the species) they cannot afford to loose limbs very often!
However, lobsters are in theory immortal and because they never really stop growing, they can therefore (in theory!) undergo molts forever!
This is one reason why lobsters are so expensive to buy. Aging to large size under natural conditions is very slow and many do not survive to old age due to all the things lobsters get caught up in like fishing nets or competition for food from other lobsters.
Can a Lobster Survive Without Claws?
A lobster will typically die if it loses both claws, because the claws are so important to the lobster’s feeding and defence against predators that it needs both in order to survive.
Lobsters mainly use their claws for cracking open food and fighting off other lobsters and predators.
A lobster can only be easily killed by an enemy if its claws have been removed, so lobsters usually aim to cut off each other’s claws during fights.
Claws that have been removed are not large enough for fighting until the lobster has gone through two whole molts – and as we will see, this can take years for an older lobster!
If the lobster is not killed before that time, it will have a hard time finding a mate because its growth would have been halted due to its handicap and therefore lower chance of finding food and keeping its territory and place in the hierarchy.
However, some types of “lobsters” like the spiny lobsters (see below) do not have claws at all, and have found ways to survive without them!
Not All Lobsters Have Claws!
Do all lobsters have claws? In fact the family of lobsters called spiny lobsters do not have the large front pinchers or claws that most other lobsters have!
So having claws is not essential to being a lobster!
The same is true for slipper lobsters that have very short plate-like appendages that are not quite claws.
This is why they are sometimes confused with crayfish even though they live in saltwater (like all other lobsters, but no crayfish do). And in fact, they are more of a class on their own rather than an actual lobster or a crayfish.
The spiny lobster is sometimes referred to as crawfish or crayfish, especially in England and Ireland, but they are not crayfish in a taxonomical sense.
However, real crayfish are much smaller in size, ranging from two to six inches in length and do not tolerate sea water and can breathe more easily on land. Lobsters are largely unable to stay on land like some terrestrial crabs and crayfish can.
Most lobsters, however, are typically at least ten inches in length when caught for food, although some species may grow even bigger!
How do spiny lobsters defend themselves?
Without claws, it can be hard for spiny lobsters to defend themselves, but they have a few other tricks up their sleeves!
When spiny lobsters feel threatened, they will quickly scurry away to safety. If they are unable to escape, they will use their large tails to swat at predators or hide themselves by wedging themselves into small crevices.
They also keep together in groups in an attempt to deter predators. However, it does not always end out well as seen in this video:
As seen in the video, spiny lobsters will readily loose their limbs, which might actually be a defence strategy rather than a weakness!
Self Amputation in Lobsters
The phenomenon of lobsters shedding limbs to escape being caught by a predator is similar to what occurs in lizards.
In lizards, a tail will detach to distract an attacking predator.
Thus, lobsters may wilfully cut a claw off if it becomes trapped in the hopes of escaping.
Some lobsters are even comfortable with the idea of eating their amputated claw, in the hopes that regrowth of the claw will be improved by the protein in the missing limb.
What Other Limbs Can Lobsters Regenerate?
Lobsters have an incredible ability to regenerate body parts during the course of their life. They can regrow feelers, claws, walking legs, and even smaller portions of their tail region.
All arthropds can regenerate, or re-grow lost limbs after molting. This includes both the high and low phylums (Mollusca and Arthropoda, respectively). Arthropods in the phylum Mollusca include crabs, crayfish and numerous insects.
The process of regenerating neurons involves converting blood cells into fully functional brain cells. A type of self-administered stem cell therapy!
Can Lobsters Regrow Their Antenna?
Yes, lobsters can indeed regrow their antenna and they are one of the limbs that are fastest to replace in lobsters and crayfish.
Lobsters are recognizable by the long antennae that extend from their bodies used to navigate and smell/taste the surroundings.
They have a long pair of antennae and a short pair of antennae. The short antennae can also be called ‘antennules.’ They are used for detecting (“smelling”) the chemical contents of the water.
Lobsters can tell a lot about the world around them by the taste of the water around them. They can also taste their food with these antennae. The longer pair of antennae on lobsters helps enhance their sense of touch.
Lobsters can use these long antennae to feel the layout of the terrain around them. They can also sense other lobsters.
Antennae can also be used to detect the movement of water around them, which can help lobsters detect nearby predators or potential prey.
Can Lobsters Grow their Legs Back?
Lobsters can grow back lost legs, antennas and claws. The process of growing back legs is similar (but faster) to the lobster regenerating its lost claws.
As the leg begins to regrow, it will strengthen and grow bigger during each time the lobster molts.
Lobster missing legs may not be able to swim as quickly, making them more susceptible to attacks from predators. Hence, lobster will have to be careful to stay alive while it regenerates missing legs.
If they want to move more quickly, they can also their strong tail parts to swim in explosive bursts to escape predators!
The ten legs of lobsters include the claws and the tiny pinchers of the second (and sometimes also the third) most front legs. Technically, these two pairs of claws are less involved in walking, and more involved in feeding, than the rest but are still considered legs.
The remaining “real” legs are all in matched pairs along the side of the body and tend to regenerate faster than the claw-equipped front legs because they are smaller.
Can Lobster Regrow Eyes?
Lobsters are frequently studied as model systems for learning about arthropods regeneration.
As of now, there is no evidence of lobsters re-growing functional eyes, and most scientists do not expect that lobsters can fully regenerate their eyes once lost.
However, scientists are currently studying the process by which lobsters regenerate neurons including those involved in light sensing that constitute their eyes!
These scientists hope to learn if this knowledge could be applied to the medical field and help humans heal from brain- and neural injuries.
However, the eye structure of a lobster seems to be too complex to fully regenerate once damaged.
Can lobsters regrow their tails?
Lobsters can regenerate many lost appendage including claws, legs, and antennae, but they cannot regenerate their entire tail!
The tail of a lobster is an integral part of their body, containing not only muscles (which can regenerate) but also vital organs and complex nerve tissue.
Therefore the lobster cannot regenerate an entire lost tail. However, it is able to regenerate the very tip of the tail as long as no organ damage or elaborate nerve destruction has occurred!
Can lobsters live without their tail?
No, if a lobster loses its entire tail, it will likely be too injured to survive and it will, at best, be unable to move fast enough to escape predators.
This is likely also a reason why they do not regenerate it, because even attempt molting and regeneration of the tail will not be possible before they die from their injury.
The tail of a lobster should not be seen as a dispensable appendix like a claw, a leg or even an eye, because the tail is as integral a part of the lobster’s body as e.g. the tail of a snake – it IS the body!
Therefore, whereas a lobster losing a small part of the outer tail fin may survive (and regenerate) just fine, losing a significant portion of the tail will most certainly be fatal to the lobster.
The same would be true for crayfish as well.
If you are more interested in the curious physiology of crustaceans, don’t miss out on my posts about how octopi, squids, and crayfish breathe under (and above) water or how crayfish and lobsters have evolved to live in their different habitats of salt and freshwater!
How Many Times Can A Lobster Molt?
On average, a lobster will molt once per year. More if they are young and male. Less if they are old or female. The American and the European Lobster most annually, while the Spiny and the Squat Lobster molt up to twice (four times per year).
How Fast Does A Lobster Grow?
The growth rate largely depends on the species, but the entire growth process takes several years. Generally, a Lobster can use the energy from a single molt to grow up to 25 % and the time to rebuild a limb is around eight weeks.
How Long Do Lobsters Live? Are They Immortal?
Most Lobster species have an average lifespan of 10 to 60 years. But some American and European Lobster have lived to be over 100 years old!
Whereas lobster’s cells in theory do have the unique ability to divide endlessly because they possess a specific enzyme (telomerase) at high levels, this is rarely sets the limit for the lifespan of any wild animal, and they will wear down in other ways instead.