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Why do hermit crabs lose legs?

Are Hermit Crabs Legs Supposed To Fall Off?

New owners are horrified to discover that a pet hermit crab has lost a leg. You may be surprised to learn that this is common as hermit crabs shed limbs regularly.

The loss of limbs often happens when hermit crabs are stressed, so check the conditions of the tank. A lack of humidity, the wrong temperature, or unsanitary living conditions can cause distress.

Hermit crabs shed limbs to relieve discomfort caused by injury or parasitic infestations. The loss of legs can be a sign that hermit crabs are preparing to molt.

The loss of limbs isn’t a death sentence for hermit crabs. Equally, it’s not something to shrug off and consider normal hermit crab behavior.

Learn what happens when hermit crabs shed limbs, and why it occurs.

My Hermit Crab Lost a Leg

If you find a severed leg in a hermit crab enclosure, you will understandably be shocked. This suggests that something terrible has happened, which may be the case.

Hermit crabs shed limbs for a wide array of reasons, sometimes it is even by choice.

Hermit crabs can shed limbs organically, usually as a result of stress. In other cases, the leg has been willfully severed. This may have been done by the hermit crab itself or due to conflict with a tankmate.

Can Hermit Crab Legs Grow Back?

As per The Biological Bulletin, hermit crabs can regrow lost limbs. All regenerated limbs are not created equal, though. The smaller legs, found at the rear of hermit crab anatomy, typically regrow faster.

The speed of limb regeneration is tied to the purpose of the appendage. The fourth and fifth pairs of hermit crab legs are primarily used to access shells and groom, which makes them essential for survival.

The same could also be said of other legs. The third and fourth pairs of legs are for walking, while the pincers (often considered the foremost pair of legs) are used for eating, climbing, and self-defense.

Hermit crabs can make do without these limbs for a while, though. Most will wait until their next molt before regenerating these legs. Until then, the hermit crab will just be a little more cautious.

Can a Hermit Crab Live without a Leg?

As intimated above, hermit crabs can still live a full life with a missing limb. They have enough spares to make do until the leg regenerates. Even the loss of a large claw is not terminal to hermit crabs. Just learn why the limb was shed as it may point to a bigger issue.

If a hermit crab lost all its legs in quick succession, it’s sadly a different story. These hermit crabs are invariably dying. You may be able to nurse such hermit crab back to health, with patience and good fortune. Hermit crabs do not shed all ten limbs without reason, though.

If you find hermit crabs in this condition, they must be handfed, bathed, and protected from other hermit crabs. A complete inability to defend themselves makes them easy pickings for shell eviction.

If you find a hermit crab with no limbs, the most humane thing to do is euthanize it. Place the hermit crab in an icebox overnight, sealed in a container. The cold temperatures will quickly anesthetize the hermit crab and it will quietly pass away.

why do hermit crabs legs fall off?

Why Do Hermit Crabs Lose Legs?

“Why do hermit crabs’ legs fall off?” is a question posed by all novices. As discussed, the loss of a single limb per hermit crab is to be expected. It shouldn’t go ignored, but it can be explained.

There are many possible reasons for hermit crabs to lose limbs. Let’s take a look at the varied explanations.


Hermit crabs are easily stressed, especially in captivity. You should make every effort to imitate the natural environment of hermit crabs. This is the only way to help them adapt to life in an aquarium. The stress caused by change can influence limb shedding.

Loss of limbs is often accompanied by hermit crabs entering willful isolation. The hermit crabs may remain buried under substrate for prolonged periods, or just hide in corners. As hermit crabs are social, this usually suggests that stress is to blame.

Stress may be common in captive hermit crabs, but it remains a serious concern. Emotional disquiet can have a significant impact on the health of these animals. Limb shedding is the first, prominent warning sign that something is amiss.

If you feel that your hermit crabs are stressed, identify why. Inappropriate living conditions are often to blame. There could be another issue though, including unsavory inter-crab dynamics. Whatever the cause of stress in hermit crabs, it needs to be resolved ASAP.

Inappropriate Tank Conditions

As discussed, you have a responsibility to your hermit crabs to ensure their tank conditions are suitable. An unpleasant – or even imperfect – living space is the biggest cause of stress. To keep your pets happy and healthy, ensure the tank contains:

  • Humidity of 80%
  • Temperatures of around 80 degrees Fahrenheit
  • Plenty of substrate – ideally at least six inches
  • Saltwater and freshwater for drinking and bathing
  • A varied diet
  • Company – hermit crabs grow stressed and lonely living alone
  • Hiding places, such as rocks and plants
  • Climbing apparatus for recreation and other toys

If your hermit crabs are shedding limbs regularly, living conditions are almost certainly to blame. This must be rectified as a matter of urgency. The lives of your hermit crabs depend upon your actions.

Excessive Stimulation

Excessive stimulation can make life miserable for hermit crabs. Do all you can to provide them with a quiet life. This means not too much noise, limited handling, and an appropriate light and dark cycle.

Hermit crabs are nocturnal. This means that they are used to spending time in darkness. If you expose hermit crabs to constant light, they will grow distressed. Dim or switch off heat lamps at night and avoid placing an aquarium in a direct light source.

Noise is also a concern. They may not be used to the constant chatter of human beings. Also, constant thumping or other loud dins will be distressing.

Hermit crabs hear through vibrations, so music is not outlawed. Some hermit crabs will enjoy the rhythmic vibrations caused by bass-heavy speakers. Keep the volume to a safe level, though. If your hermit crabs appear disoriented, they are confused by the noise.

Only touch hermit crabs when necessary. Handle your pets periodically to build trust. This makes it less likely that you’ll be pinched while handling ahead of tank cleaning. Hermit crabs are not cuddly pets, though. Leave all ten feet on the ground as much as possible.

Bullying from Other Hermit Crabs

Hermit crabs are social and like their own kind. Once a hermit crab colony is established, a pecking order will be decided. All groups of hermit crabs have at least one dominant hermit crab, with others falling in step.

There can be a thin line between dominance and bullying. Hermit crabs that sit at the apex of a social pyramid can create trouble for their subordinates. These animals may constantly attempt to steal shells from submissive hermit crabs, for example.

Food, toys, and territory may also be hoarded. This will become increasingly stressful for the victim of the bullying. It will feel unsafe in its habitat but have nowhere to flee to. Thankfully, this behavior is comparatively rare.

Most hermit crabs co-exist without these problems becoming unsustainable. If you do notice dominance going too far, separate your hermit crabs into separate habitats. House the bully with hermit crabs that can stand up for themselves, and the victim with more docile tankmates.

Struggling with Life in Captivity

Some hermit crabs struggle more than others in captivity. Most hermit crabs eventually adapt to life as pets. Some will never seem happy. These hermit crabs will live in a constant state of distress, shedding limbs all the while.

Ask yourself if you have done everything you can to settle your hermit crabs. This could include upgrading accommodation to a larger tank. Hermit crabs are used to have an entire beach to explore, so more space will be welcomed.

If your hermit crabs remain miserable in captivity, do not just release them into the wild. Hermit crabs need saltwater to survive. They won’t find this in a city or suburb. They’ll be dead in less than 24 hours.

Equally, do not just release hermit crab at the nearest beach. Different breeds of hermit crab are native to varying parts of the country. Releasing hermit crabs in unfamiliar terrain could create an invasive species that wreaks havoc upon the eco-system.

Search online and find a hermit crab specialist in your area. These individuals will know how to proceed. They will find the hermit crabs a more appropriate captive home or get them to their home terrain.


Limb shedding also occurs in hermit crabs following injury. If a hermit crab is in pain or discomfort after a physical mishap, shedding a limb may be the lesser of two evils.

Hermit crabs would rather have nine healthy, active legs than one useless limb that acts as a hindrance. These injuries typically stem from one of three explanations.

Fights with Other Hermit Crabs

We previously touched upon the problem of bullying among hermit crabs. Even if hermit crabs do largely get along, they will attack each other occasionally. Some of the explanations for this include:

  • Plays for alpha crab status
  • Squabbles over food or territory
  • Battling for the affections of a fertile female
  • A war over superior shells
  • Unprovoked aggression from a cantankerous crab

Not all hermit crab fights turn nasty. Oftentimes, hermit crabs will resolve their differences as amicably as they can. If a hermit crab is angered, though, it may attempt to sever legs with the pincers. Equally, if a hermit crab is hurt in conflict, it may cut off its leg.

Nervous hermit crabs may also shed legs to distract an aggressor. This buys time for the victim to escape. As hermit crabs rarely fight to wound, it is unusual for these animals to display such volatility.

Falls from Height

Hermit crabs are natural climbers. They like to clamber up the side of an enclosure for fun. Hermit crabs also sleep hanging from a tank ceiling and, as per the Journal of Ethology, climb to avoid confrontation.

The laws of physics dictate that what goes up must come down. With luck, your hermit crabs will safely negotiate passage back to the ground. They can fall from a height, though. Even if the fall is not fatal, it may lead to limb damage.

If hermit crabs break or injure a leg through falling, the limb will be severed by the claw. Hermit crabs know that this limb is now useless. They decide to wait for the regeneration of the leg during the next molt.

can hermit crabs legs grow back?

Inappropriate Handling

Learning how to safely handle hermit crabs is among the first skills a new owner must learn. In reality, they do not enjoy being handled. Sometimes it will be unavoidable. You’ll need to pick up hermit crabs to rehouse them ahead of cleaning a tank, for example.

Hermit crabs must always be picked up the shell. Grab the shell firmly, then place the crab in your hand as quickly as possible. Do not leave the hermit crab hanging in mid-air.

If you try to handle a hermit crab by the legs, its limbs will fall off. Hermit crabs never relinquish a shell unless necessary. Tugging hermit crabs by the legs makes them think you are trying to forcibly evict them. They would rather lose legs than their shelter.

Shell Selection

Choosing an appropriate shell is critical for hermit crabs. A shell needs to offer protection, mobility, and privacy. The more hermit crabs molt, the more they need to change shells. This makes the availability of such shelters increasingly rare.

As a result, some hermit crabs willfully shed their large claw. Also known as the major celiphad, the large pincer is used in self-defense. If the claw is shed in conflict, the hermit crab will flee.

As per Crustacean Research, hermit crabs change shell much less frequently after shedding the major celiphad. This suggests a willing choice by the crab. The loss of claw is preferable to molting and seeking a new shell. Such activities leave hermit crabs completely vulnerable.

If a claw fell off, not moving may follow. The hermit crab is hiding and destressing within its shell to recover from its ordeal. The hermit crab should recommence movement after a few hours, especially when hungry.

Preparing to Molt

Some hermit crabs will willingly shed limbs ahead of molting. This is most common if the crab is outgrowing an existing shell. Hermit crabs can get stuck in their shells. If the hermit crab is not willing to give up a shelter just yet, it may shed limbs to fit inside for a while longer.

Hermit crabs are largely nonplussed if they lose limbs when a molt is pending. They know these limbs will grow back. Oftentimes new limbs are initially weak, especially the pincers. Ensure the hermit crab is safe upon concluding a molt.

This means providing an array of shells for the hermit crab upon emergence. If possible, move your hermit crab to a private tank and let it molt alone. Once the process completes, and the crab has an adequately protective shell, it can rejoin its tankmates.

Mites and Other Parasites

Parasites can impact all domestic pets, and hermit crabs are no exception. As explained by the Israel Journal of Ecology and Evolution, Andrégamasus steinitzi and Andrégamasus branchiophilus mites are commonly associated with hermit crabs.

Mites may make their way into a hermit crab tank through imported food. Equally, these tiny insects can work their way into a tank through microscopic holes. Mites are attracted to the humidity of a hermit crab enclosure, in addition to uneaten food waste.

If mites attach to hermit crabs, they should be just about visible. These parasites live on the legs, eyes, and abdomens of hermit crabs. To relieve the discomfort these invaders cause, hermit crabs may sever limbs. Keep an aquarium clean to minimize the risk of infestation.

It would be a push to say that hermit crab legs are ‘supposed’ to fall off, any more than hermit crabs can lose their eyes, but it is a common occurrence. If you find shed limbs in your tank, identify which hermit crabs are shedding and why.