Hermit crabs often shed limbs, most often the rear legs. Hermit crabs can also shed claws by choice, injury, illness, or accident. Unfortunately, losing a claw is more significant than losing a leg.
Hermit crabs lose claws when stressed. This could result from poor living conditions, too many hermit crabs in a small space, or boredom. A hermit crab may have been exposed to toxins in water or cleaning products or have been fed a poor diet leading to a compromised exoskeleton.
Sometimes, hermit crabs shed their claws by choice. This may happen if your hermit crab hurts its claw, especially if it knows it’ll soon molt and grow a replacement.
A hermit crab can live with a missing claw, especially if it’ll shortly molt, but some lifestyle adjustments will be necessary. It may be advisable to relocate a one-clawed hermit crab to an isolated tank or provide just one or two friendly conspecifics for its protection.
Two mismatched claws, one large and one smaller, are vital signs of a happy and healthy hermit crab. If one cheliped has been shed, you must find out why it has happened.
Is it Normal for Hermit Crabs to Lose Claws?
Hermit crabs often shed limbs when sick, stressed or injured. Hermit crabs have ten legs – including the chelipeds – losing one or two legs won’t significantly impact their quality of life.
The claws of a hermit crab tend to be sturdier than the limbs found behind, so it’s rarer for a hermit crab to allow a claw to be shed. Something has happened if you find a claw on the ground.
There will not be a quick fix for a hermit crab that has lost its claw.
Can Hermit Crab’s Claws Grow Back?
Thankfully, any loss of a hermit crab’s claw will be temporary. Hermit crabs undertake a full molt every 18 months (more often for juveniles.) A molt involves a complete shedding of the exoskeleton and growing a replacement, including lost claws and legs.
If a hermit crab loses a claw, you won’t find blood in the habitat, as the process doesn’t cause bleeding. You’ll notice a white bud at the base of where the claw once was. This is the beginning of the regeneration process that’ll unfold during molting.
At the end of a molt, your hermit crab may have an entirely new claw. Alternatively, it could take two or even three molts to regenerate a claw completely, but one molt will be enough to get your hermit crab fully functional again.
If it’s going to be a while before your hermit crab is scheduled to molt, it’ll need to learn to adapt to life without a claw. There isn’t a quick resolution.
Can a Hermit Crab Survive without its Claw?
To answer this, we first need to address the primary functions of the claws of a hermit crab.
The large cheliped is typically used in self-defense, to cut food into bite-sized chunks, and to climb. The main function of the smaller cheliped is guiding food into the mouth.
If your hermit crab has lost its large claw, it’ll need assistance. Food will be a primary concern, as the large cheliped cuts morsels. Offer soft food that has been chopped as small as possible.
Without a large claw, a hermit crab will also struggle to climb. This will make them unhappy, as climbing is a favored pastime of captive hermit crabs.
Ensure your one-clawed hermit crab can get out of a pool of water without help.
If a hermit crab loses both claws, it’ll struggle more. Balance when walking will be restricted, your hermit crab will likely need to be hand-fed, and it’ll be an easy target for aggressive tankmates that covet a shell.
If you believe the hermit crab will soon molt, move it to a different tank with one or two friendly conspecifics until this arises.
Why Did My Hermit Crab’s Claw Fall Off?
There are many possible reasons for a hermit crab to lose a claw, including:
Stress and Anxiety
Hermit crabs struggle with life in captivity and experience stress. The first few weeks of a hermit crab’s life as a pet will be touch and go as it undergoes post-purchase syndrome (PPS), hiding under the substrate.
After a while, the hermit crab will emerge and go about its day. You must still be mindful of managing anxiety and identifying and eliminating potential stressors ahead of time.
Arguably the single most critical component of hermit crab care is providing a captive environment comparable to the natural living conditions of these animals.
Ensure the following basic living standards are met to keep your hermit crabs from growing so distressed they lose limbs and claws:
- Temperature no lower than 72OF and no higher than 82OF – 80OF is considered the sweet spot.
- A humidity level of 80%. If a hermit crab’s environment is too dry, it’ll start shedding limbs.
- Enough space for all hermit crabs to carve out their territory.
- The contrast of light and darkness, ideally 12 hours of each.
- Safe, quiet surroundings – as per Behavioral Ecology, constant noise leaves hermit crabs confused and disoriented.
Failure to meet these expectations and stress will quickly follow.
Life can get dull for captive hermit crabs. Your pets will grow increasingly distressed if you don’t provide enough recreational activities, which can lead to drastic action, including self-mutilation.
Always ensure hermit crabs have conspecifics in a tank. Coral Reefs confirms that hermit crabs forge bonds, returning to an established colony if separated. Forcing a captive hermit crab to live alone causes stress and remove the ability to play and socialize.
Hermit crabs sometimes get trapped between objects, such as decorative rocks, which can create panic. If the hermit crab feels that it has no other exit route, it may sever a large claw to reduce its body mass and escape its predicament.
Fighting a Conspecific
Hermit crabs usually get along well and enjoy each other’s company.
Playfighting with the feelers is an everyday part of hermit crab life and is no cause for concern. The same applies to pushing each other over, which is a test of strength and a way of asserting a social hierarchy.
Sometimes, these good-natured interactions will turn sour. Hermit crabs may start actively fighting, attempting to pinch with the chelipeds.
This can result in losing a claw or other body parts – the eye stalks are most at risk.
Exposure to Toxins
You may be surprised by how many hazardous toxins can impact a hermit crab. Common examples of toxins that could make hermit crabs sick enough to lose a claw include:
- Copper and chlorine in unfiltered tap water.
- Iodine in table salt – never uses this to create saline water.
- Paints are used on a decorated shell.
- Bleach and aerosol fumes are used in cleaning a tank and the surrounding area.
Avoid any use of unnatural or dangerous chemicals around your pet hermit crabs.
Hermit crabs are natural scavengers in the wild and find the nutrition they need daily. In captivity, your responsibility is to provide hermit crabs with a suitable diet, which means calcium and protein.
Calcium and protein are the building blocks for a robust and sturdy exoskeleton in hermit crabs. Add cuttlebone to the habitat to encourage consumption of the former.
If your hermit crabs don’t eat an appropriate diet, their exoskeleton will suffer. Prolonged malnutrition can weaken the exoskeleton and may result in a loss of claws.
Inability to Enter Shell
Hermit crabs grow very attached to their shells. According to the Journal of Crustacean Biology, hermit crabs choose shells that reflect their bodies’ size. Hermit crabs like their homes to be snug fit.
The large cheliped is the last part of hermit crab anatomy to enter a shell. It’s often used to block the ‘entrance’ to the shell, protecting its occupant and providing privacy.
A stubborn hermit crab may choose to sever its large claw if it becomes too big to fit inside a cherished shell. Encourage the hermit crab to trade up to a new shell before this becomes necessary.
Hermit crabs can struggle with mite infestations.
These tiny bugs will attach themselves to a hermit crab’s skin, driving it crazy with itchiness. Some hermit crabs sever their limbs in an attempt to relieve this discomfort.
You won’t necessarily notice mites in a habitat without the aid of a magnifying glass, so learn the behavioral warning signs of an infestation.
If you believe mites live in a tank, all occupants must be treated and the tank thoroughly cleaned.
Preparing to Molt
If a hermit crab knows it is scheduled to molt, it may willingly shed a limb or claw.
This is likeliest if the claw has imperfections, such as minor injury. A hermit crab would sometimes rather lose a frustrating appendage and start over.
If your hermit crab loses its claw, look for these other symptoms of impending molt:
- Glassy eyes
- Digging to excess (if possible without a claw)
- Lethargy and a reluctance to move
- Eating to excess (storing fat)
- Drinking and bathing more (storing water in the shell)
If these signs are present, your hermit crab will soon start molting. Consider moving it to an isolated tank so the molt can be concluded in peace.
Losing a claw needn’t be a disaster for a hermit crab, but neither is it ideal. If your hermit crab loses a large or small cheliped, learn what caused this to happen and monitor your other pets.