Unlike most crabs, hermit crabs do not scuttle sideways. Instead, they lift their bodies and propel themselves in a straight line. This is because hermit crabs have different anatomy to other species of crabs.
Hermit crabs use their front and back pairs of legs to walk. These legs are supported by 6 pereopods, appendages below the abdomen that act as additional legs. Pereopods carry the weight of a shell and help the hermit crab drag itself forward. They lift their belly from the ground while walking, unless their shell is too heavy.
Hermit crabs are not known for their rapid movement. Your hermit crabs should walk around their aquarium, exploring and climbing. If your hermit crabs are refusing to move, something is likely amiss with their health.
How Does a Hermit Crab Move?
Hermit crabs have 3 primary modes of movement – walking, burrowing, and climbing. Hermit crabs utilize these latter techniques more than you may think. Faced with an obstacle, most hermit crabs prefer to climb over or burrow under than walk around it.
At a glance, hermit crabs appear to have 10 legs. In reality, hermit crabs have 4 walking legs, at the front and rear of their body. These are supported by 6 pereopods. Pereopods are appendages attached to the thorax. These are all necessary for walking.
As explained by Arthropod Structure & Development, the walking legs of hermit crabs are aided by the pereopods. Four of these pereopods carry the weight of the hermit crab’s shell. The remaining two aid with walking, digging into a ground surface, and pull the hermit crab forward.
Hermit crab legs bend backward and forward, propelling them into motion. Usually, hermit crabs will lift their belly from the ground while walking. Those that carry particularly heavy shells may drag their abdomen on the ground, though.
Do Hermit Crabs Walk Sideways?
Most breeds of crab are noted for shuffling sideways, not forward. In reality, all crabs can move forward, backward, or even diagonally. Sideways movement is just the fastest way for crabs to get around.
This is due to the anatomy of the legs. The legs of the crab are stiff, with a joint in the middle. This is akin to the hinge of a gate, though it swings from left to right rather than back and forth. By walking sideways, a crab will not trip over its own feet. Each leg moves independently of the others.
Hermit crabs are a little different. Their leg joints allow for backward-and-forward movement. In many respects, hermit crabs are more flexible than other crustaceans. Linear, forward movement comes more naturally than sideways shuffling.
Can Hermit Crabs Walk Backward?
Hermit crabs can walk backward, but prefer to face forward. This enables a hermit crab to smell food and threats, using thin hairs on their antennae known as aesthetascs.
Hermit crabs are likelier to make a sudden move backward if they feel threatened. Hermit crabs do not move at speed. They are at the bottom of the seafront food chain and face many risks from predators.
Instead of fleeing danger, hermit crabs are likelier to lurch backward then hide in their shell. You will notice long, tall legs emerge, and the crab will take two of three lunges backward. This buys time and puts distance between itself and danger. If the hermit crab has a sufficiently robust shell, it will hide within until danger passes.
Can Hermit Crabs Walk on Carpet?
Hermit crabs like to move on smooth surfaces. They will never have encountered carpet in the wild. As a result, it is advisable to place them on such material. Hermit crabs are likely to latch onto carpet fibers and become reluctant to move.
If you want to exercise your hermit crabs outside their tank, place them in the bathtub. This will be a safe place for them to wander and explore. You could also place hermit crabs on a flat table surface. Watch them carefully in this instance, though.
Hermit crabs have poor eyesight and do not tend to slow down once they have built a head of steam. If a hermit runs, it may clear the edge of an elevated surface. This can lead to a dangerous fall. Thankfully, hermit crabs are slow so you’ll have time to react.
Can Hermit Crabs Walk After Shedding Legs?
Hermit crabs shed their entire exoskeleton every time they molt. Some hermit crabs also shed individual limbs. Your hermit crabs will still be able to walk after losing one set of legs. The pereopods continue to enable movement. Eventually, the lost legs will grow back.
This does not mean that you should ignore the shedding of legs, though. This is often a sign that your hermit crab is stressed or anxious. Alternatively, it may have a mite infestation. The shedding was an attempt to resolve this. Clean the tank ASAP.
It is surprisingly easy to tear off the legs of a hermit crab. This is why you must never tug hermit crabs from their shell. They guard their shells with their lives. They would rather relinquish legs than give up their haven.
As explained by the American Journal of Physiology, hermit crabs also shed limbs after injury. If a hermit crab hurt a leg in conflict, for example, it will remove the remainder with its claw. A fall from a height may also inspire this action.
When Do Hermit Crabs Move Around?
Hermit crabs are nocturnal by nature. This means that your hermit crabs will typically only move at night. You will need to wait until after dark to watch your hermit crabs go about their business as standard.
When the sun goes down, hermit crabs will emerge from their hiding places. This often means appearing at the surface of a substrate. Most hermit crabs sleep while burrowed. The hermit crabs will then seek food and entertainment.
If you meet these needs, your hermit crabs should be active. Hermit crabs like to dig, climb, and wrestle each other. Happy, healthy hermit crabs will not be lazy or lethargic, especially during evening hours.
How to Get a Hermit Crab to Move
If you want to encourage your hermit crabs to move, give them a reason to do so. The easiest way to do this is by stimulating the senses. Food will usually be effective for this.
Ensure there is sufficient saltwater in the hermit crab enclosure. This greatly enhances the sense of smell of hermit crabs. Now, place a favored snack in the habitat. Grapes or oats will often garner a reaction. You will likely find your hermit crabs make a beeline for their food.
Making a hermit crab aquarium fun will also encourage movement. Hermit crabs are playful animals. If they have plenty of surfaces to climb and terrain to explore, they will happily do so.
If you want your hermit crabs to move faster, create a gust of air behind them. This could be done by simply blowing or using a hairdryer in low heat. This invariably encourages hermit crabs to scurry forward. It can also provoke stress though, so use this tactic sparingly.
How Fast Do Hermit Crabs Move?
Hermit crabs are not famed for their speed of movement. According to the Journal of Experimental Marine Biology and Ecology, the average hermit crab walks at just 2 MPH. That is a velocity roughly in line with a tortoise.
This does not mean that hermit crabs cannot move faster when they wish. Some hermit crabs run for fun. Others grow agitated and display a, fight-or-flight instinct under duress. Usually, though, hermit crabs will amble at their own pace and rarely zip around.
Why Are My Hermit Crabs Moving Slowly
As discussed, hermit crabs are slow-moving as standard. There will always be exceptions to this. Some hermit crabs will gleefully run for recreation. Most will be a little more lumbering, though.
If you are concerned by the speed at which your hermit crabs move, consider the possible explanations for this sluggishness.
Large or Heavy Shell
For hermit crabs, a shell is a home. This means that, like humans, hermit crabs will choose the largest dwelling they can. The bigger a hermit crab’s shell, the less likely it is to need to change with the growth of the exoskeleton.
It is not uncommon for small hermit crabs to tote large, heavy shells on their backs. This will make movement difficult. The hermit crab will be unable to generate sufficient leg power to move at speed. It will feel akin to carrying a backpack filled with heavy rocks.
Never attempt to force hermit crabs out of their shells. Eventually, they will decide to downsize to something more appropriate. This will aid movement. Alternatively, the hermit crab will molt and grow in mass, making it easier to support the shell’s weight.
Trapped Within Shell
Hermit crabs can become trapped in their shell. This occurs when a hermit crab grows too large for its chosen shell. The exoskeleton gets wedged in the vessel, and the hermit crab cannot move at speed. The legs are restricted by this entrapment.
Hermit crabs also get stuck in painted shells. If you purchased hermit crabs from a seafront gift store, they were likely placed in freshly-painted shelters. If this was the case, wet paint may have glued the hermit crab’s exoskeleton inside.
Offer plenty of saltwater for bathing. The more time a hermit crab spends submerged in this water, the easier it will be to slip out of the shell. Once this is done, offer an alternative shelter as quickly as possible.
Preparing to Molt
Molting is not an overnight undertaking for hermit crabs. They prepare for this act well in advance. This gives hermit crabs the greatest chance of survival a molt. If Your hermit crab is growing lethargic, look out for these additional signs and behaviors.
- Color fading to a dull gray
- Glazed, milky look in the eye
- Eating more than usual. The crab is storing fat in the existing exoskeleton for sustenance while molting
- Drinking and bathing more than usual. The crab is keeping water in its shell so it can remain hydrated while molting
- Digging in numerous locations, as though seeking the perfect burial spot
If these apply, your hermit crab is likely getting ready to molt. Young male hermit crabs, in particular, molt several times a year. If you spot these signs, isolate the molting hermit crab in a separate tank. It will appreciate the chance to molt in peace and safety.
Why Isn’t My Hermit Crab Moving?
It is always concerning when hermit crabs cease movement. Do not immediately suspect the worst, though. Your hermit crab may be sleeping or molting.
Undertake a process of elimination to understand why your hermit crabs are not moving. f you still cannot find a reason for your hermit crab’s lethargy, it may have passed away.
Dead hermit crabs release a foul, fishy smell. This is the first clue that a hermit crab has expired. Other hermit crabs will surround the corpse. They are sizing up the now-vacant shell. Before assuming that the hermit crab is dead, though, eliminate other possibilities.
Sleeping or Molting
Most hermit crabs choose to burrow under their substrate to sleep or molt. This is not always the case, though. Some hermit crabs will molt in the open, or a hiding place such as behind a rock.
Never disturb hermit crabs in these circumstances. You will need to be patient. Molting can last several months, in some cases. It may be frustrating, but you need to leave molting hermit crabs alone. The shock of being moved mid-molt can be fatal.
Stress and Anxiety
Life in captivity can be stressful for hermit crabs. They rarely breed in captivity, so your pets likely started life in the wild. They would have been plucked from the beach and possibly kept in unsuitable conditions. What’s more, they now need to adjust to humans and our foibles.
Stressed hermit crabs keep themselves to themselves. They hide in their shells, only moving when strictly necessary. Your hermit crabs likely do move. They just save this activity for when all is quiet around them.
Eventually, your hermit crabs will gain confidence. Just focus on making the habitat as welcoming as possible. Ensure sufficient humidity and temperature are retained, offer a varied diet, and avoid unnecessary stimulation.
Some hermit crabs are naturally more cautious than others, though. This is especially common in small crabs with desirable shells. They worry that movement will open them up to challenges for this shell.
As discussed, hermit crabs are nocturnal. They have a natural understanding of when darkness should fall. If their habitat is too bright, though, hermit crabs will remain dormant. They assume it is not yet time to emerge.
Ensure that your hermit crabs enjoy reliable 12-hour cycles of light and dark. Do not leave lamps on in a hermit crab habitat 24/7. This includes heat lamps. If you house hermit crabs in a bedroom, turn out the overhead lights to match the darkness outside.
If you start to practice this, your hermit crabs will re-establish a reliable circadian rhythm. As a result, they are likelier to become active and mobile when expected.
If you have exhausted all other potential explanations, your hermit crabs may be sick. Sadly, few conventional veterinarians understand the complex care requirements of hermit crabs. This means that you are better off preventing ill health than curing what ails hermit crabs.
Lack of Humidity
If your hermit crabs have become lethargic seemingly overnight, check the humidity level of their enclosure. Hermit crabs need a humidity level of around 80%. Anything less leaves the hermit crabs at risk of suffocation. This will naturally impact energy levels.
Get a hygrometer to keep an eye on the humidity in an enclosure. Check this at least three times a day. Any time the humidity looks at risk of dropping below a safe level, use a misting spray.
If this keeps happening, question why. Humidity is escaping the tank, so check for any cracks or holes. Consider the application of sponges to increase humidity, and apply Saran wrap to the roof. This will retain moisture.
Consumption of Toxins
Hermit crabs are not shy about eating anything they encounter. Like many animals, this is how hermit crabs explore the world around them. Unfortunately, hermit crabs are also easily poisoned. Common toxins that impact hermit crabs include:
- Chlorine and heavy metals found in tap water
- Heavy metals found in flakes from painted shells
- Bacteria and mold growing in unsanitary living conditions
Aiding a sick hermit crab is a tightrope. On the one hand, handling may cause unnecessary stress and kill the hermit crab. On the other, it should be isolated from others as illness can be contagious.
If you think your hermit crab can cope, move it to a private tank. Provide everything it needs. That means fresh and saltwater, food, toys, and of course, a layer of a substrate. Watch the crab carefully. If it returns to health, restore it to the main tank.
Hermit crabs walk in a different way to most crabs. This means you should not be concerned if your hermit crabs do not scuttle sideways. This is par for the course with these animals. What matters is that your hermit crabs do move around, especially after dark.