Burrowing is a common and natural behavior for hermit crabs. All hermit crabs like to dig and submerse themselves in the sand. They’re particularly likely to do so immediately after being rehomed as it’s a stressful experience.
The most common reason for a hermit crab burrowing is when it’s molting its exoskeleton. This leaves it vulnerable to predators. The hermit crab will remain under the sand until its new exoskeleton has grown. Other reasons for burrowing behavior include destressing, moderating temperature, foraging, and recreation.
Whatever the reason for a hermit crab burrowing, it must be left alone. Never dig up a hermit crab that’s hiding as it will resurface when it feels ready to do so.
My New Hermit Crab Buried Itself Underground
Before bringing a hermit crab home, you need to create an appropriate environment. A major part of this is a deep substrate – ideally sand. Provide a minimum of three inches of sand, preferably more. Your hermit crab should be able to completely submerge itself.
The key triggers for burrowing are stress and molting, though. Moving location and becoming a pet is stressful for a hermit crab. Burying itself is a coping mechanism.
If your hermit crab buries itself upon arrival in an aquarium, it’s natural. There is no need to worry, and you certainly should not dig it up. Leave your hermit crab be. It will surface and show itself when it is ready.
Why is My Hermit Crab Digging a Hole?
Hermit crabs are natural diggers. Any hermit crab will spend at least some time buried under the substrate. The most common explanation for this is molting. There are plenty of other reasons why a hermit crab would bury itself, though.
Do not panic if your hermit crab is hiding under the substrate. Be patient and let the crab re-emerge when it is ready to do so. All the same, consider why this is happening. Your hermit crab may be sending a message that is unable to verbalize.
Molting is an essential part of the hermit crab life cycle. The stress caused by rehoming may provoke molting in hermit crabs. In addition, these crustaceans regularly molt as they grow.
The molting process of a hermit crab sees the exoskeleton drop off. This makes the hermit crab vulnerable. As a result, it will burrow under sand. Over time, the hermit crab will regrow a new, tougher exoskeleton. Once this process is complete, it will re-emerge.
You can typically tell when a hermit crab is planning to molt. It will display particular behaviors. These include:
- Constant digging
- Greater consumption of food and water (storing fat and hydration)
- Bathing more than usual
- Growing increasingly lethargic
- Willfully spilling water onto sand
- Exoskeleton fading to an ashen, gray color
- Eyes beginning to cloud over
If you notice these symptoms, leave your hermit crab in peace. It needs to molt in peace, at its own pace. Under no circumstances should a melting hermit crab be disturbed.
One thing that should not be overlooked is that burrowing is fun for hermit crabs. Wild hermit crabs live on the beach. This means they burrow throughout the day. Creating tunnels is how hermit crabs get from A to B in their habitat.
Living in captivity is a new experience for a hermit crab. These crustaceans are used to living free, usually in colonies. An aquarium will protect a hermit crab from predators. It also restricts movement and removes privacy, though.
By burrowing, a hermit crab is replicating its natural environment as best it can. This will help the hermit crab more at ease. To make digging enjoyable for a hermit crab, it needs the right substrate.
As per the Bulletin of Marine Science, hermit crab substrate should be soft. Hermit crabs faced with a tough substrate, like oyster rubble, move less than those in the sand. Equally, avoid calcium stand. This will stick to your hermit crab’s body and stiffen joints.
Foraging for Food
Walked hermit crabs are natural scavengers. It may take a pet crustacean time to adapt to being fed. The hermit crab will appreciate being provided with food. All the same, instinct is a hard habit to break.
The hermit crab may be burrowing to scavenge and find food. Check that you are feeding your hermit crab enough. If food is being left behind, question why. If the hermit crab is molting underground, this is to be expected. Other circumstances will have a reason.
One explanation is that your hermit crab’s diet lacks variety. Marine Ecology confirms that hermit crabs have a diverse diet. Wild crustaceans have a wealth of plants, animal carcasses, and even fecal matter to feast upon. They rarely eat the same thing twice in 24 hours.
Try offering different foods on different days. Hermit crabs enjoy cuttlebone, for example, but not every day. Mix this up with a little fresh fruit and vegetables. You could even give a hermit crab sweet treats, like popcorn.
You may also find that hermit crabs hide and store food in their substrate. This is especially common in aquariums that host multiple crustaceans. Oftentimes, one hermit crab will express dominance over others. This crab may horde and steal food.
Other hermit crabs will hide their share to avoid going hungry. Unfortunately, they may forget where the food is hidden. This is why regular cleaning is so important. Spoiled food can be dangerous to the delicate digestion of a hermit crab.
As discussed, hermit crabs bury themselves to manage any anxiety. This is especially likely when hermit crabs are new to an environment. Burying itself in substrate gives a hermit crab the chance to take time to itself.
Buried under the sand, the hermit crab feels safe. In the wild, a crustacean in this position is safe from predators or excessive stimulation. The same logic applies to a hermit crab in captivity.
Hermit crabs are nocturnal in the wild. This means they rarely encounter humans. This is not the case in a home. Consider that hermit crabs are a popular pet for children. Suddenly, the hermit crab is surrounded by noise and interaction.
Handling, in particular, can frighten a hermit crab. Pick up a hermit crab inappropriately and it will be terrified by humans. To safely handle a hermit crab, grip the shell with your dominant hand. Place your other hand under the legs, keeping the skin tight. Let the crab grow familiar with this sensation. This will build confidence and trust.
Over time, the hermit crab will start to manage its own anxiety. It will build confidence and even learn to trust owners. Allow the hermit crab to bury itself when it deems this necessary, though. Forcing a crustacean out of hiding will magnify stress, potentially fatally.
Temperature and Light Regulation
Ecology confirms that hermit crabs bury themselves in the sand to manage their temperature. Hermit crabs need a particular temperature and humidity level to flourish.
An aquarium should always be heated to 80 degrees and have 80% humidity. Any cooler and the hermit crab will burrow under the sand to stay warm. Any hotter and it will try to escape the heat. Hermit crabs also burrow to seek humidity that eludes them overground.
Keep a constant temperature and plenty of bathing water. In addition, ensure the hermit crab has a reliable day-night lighting schedule. Never leave lights on overnight in a hermit crab enclosure. If you use a heat lamp, ensure that it dims when necessary.
Hermit crabs are nocturnal by nature. In the wild, this is a defense mechanism. Hermit crabs surface after dark when a beach is quieter. In this instance, they can feed in peace.
If your hermit crab remains buried by day, it may just be sleeping. Hermit crabs do not enjoy bright light. Try to watch for movement after dark. You may find that your hermit crab is active when the lights go out.
Over time, though, hermit crabs should adjust to human schedules. Typically, a hermit crab will emerge during daylight to feed. Natural daylight is more than sufficient for a hermit crab.
How Long Do Hermit Crabs Stay Buried?
This depends on why the hermit crab has buried itself. If the crustacean is molting, it may not surface for weeks or even months. The larger a hermit crab is, the longer the molting process takes. Destressing can take a similar length of time.
Do not worry about food during the time. Hermit crabs eat their discarded exoskeleton while molting. They will not need to surface for food. While devoid of a skeleton, hermit crabs also avoid bathing. They also eliminate less, so conditions should remain sanitary.
Hermit crabs store food and water by eating and nothing more before starting a molt. This means they will have enough nutrition and hydration. Wait out the process, leaving the hermit crab alone. This can be a worrying time, but be patient.
Is My Hermit Crab Dead Under the Sand?
After a while, it is only natural to fear that a hermit crab may be dead. It seems unnatural for the crustacean to be submerged for so long. There is no hard and fast rule for how long a hermit crab will stay submerged, though.
Never mistake the molting process for a dead crab. In both cases, the crab will seem completely lifeless. Disturbing a molting hermit crab can frighten it to death, though. This process leaves a hermit crab wholly vulnerable.
One sign of a dead hermit crab is a foul smell of rotting fish. This will be unmistakable. Live hermit crabs can also emit this smell, though. It’s the discarded exoskeleton that causes the aroma. If the exoskeleton is not reducing in size, it suggests is not being eaten.
This exoskeleton should be providing food and water to a live hermit crab. Ergo, if it remains untouched, the hermit crab may be dead. Remove the skeleton if you wish. This should resolve the smell.
Alas, it is also potentially placing a molting hermit crab at risk. It may be eating but in small increments. A safer technique is to smooth out substrate around the crustacean. Check every 24 hours for any sign of movement or tracks in the sand.
It’s hard to tell if a hermit crab is dead or just molting. To add further complications, you may inadvertently kill a hermit crab by handling it during molting. Wait at least three months before fearing the worst. After this, you may need to take your chances.
My Hermit Crab is Always Burrowing
If you have bought a hermit crab in your home, you will want to see it. Hermit crabs are not conventional pets, though. They do not interact like cats or dogs. Some hermit crabs will never willingly reveal themselves.
You’ll certainly need to be patient at first. Your initial concern with a hermit crab is keeping it alive. Many hermit crabs do not survive longer than a month in captivity. If burrowing keeps the crustacean alive, so be it.
Eventually, your hermit crab should start to grow in confidence. At this point, it will be more active and visible. If this is not the case, consider living conditions. You may need to make some changes to the habitat.
More Hiding Places
Hermit crabs often submerge to hide. All hermit crabs need some privacy on occasion. If there are insufficient hiding places in a habitat, under the sand is the only option.
Dot obstacles and hiding locales around an aquarium. This will help a hermit crab feel safer. Avoid store-bought decorations where possible. The humidity of a hermit crab habitat can cause toxic paints and dyes to run.
Rocks and wooden logs are fine. Pick these up from a natural resource. Consider boiling them in water to kill any bacteria, then place them in the aquarium. A hermit crab will welcome this mimicry of its natural environment.
Rehome the Aquarium
Hermit crabs are not used to being surrounded by people and the noises we make. A hermit crab can easily become overstimulated by this. As a result, it will submerge in the sand and hide.
If the hermit crab is housed in a bedroom, consider moving it. It will be impossible for the hermit crab to avoid noise here. Voices, television sets, stereos, and ambient sounds will all build up.
Consider moving the aquarium to a spare room or a rarely used utility room. The hermit crab can still be visited. It will be less anxious without constant stimulation, though. Once the hermit crab grows in confidence, you can consider moving the aquarium back.
Check Temperature, Humidity and Lighting
Invest in a thermometer and humidity gauge for the enclosure of your hermit crab. This way, you can ensure that conditions are optimum. Remember the golden ratio – 80 degrees and 80% humidity.
If necessary, add more humidity to the aquarium with a misting spray. You could also increase the amount of water available for bathing. Hermit crabs like a choice of fresh and saltwater for this.
Think about lighting, too. A hermit crab may find the enclosure too bright at night. Make sure all lights are switched off. If the aquarium faces ambient light, such as street lamps through a window, cover it at night.
Your hermit crab may be hiding due to boredom and loneliness. This sounds like we are personifying a hermit crab. Crustaceans do not seem to experience complex emotions. All the same, hermit crabs are social. They live in groups in the wild.
Consider adding a second, third, and even fourth hermit crab to the aquarium. Naturally, you may need to invest in a bigger habitat. In doing so, though, you’ll likely find that all the crabs are happier. They will interact with each other at the surface level.
These hermit crabs will still burrow on occasion. Although they are social, hermit crabs need time alone. Equally, molting hermit crabs still burrow. If you notice signs of molting, move the hermit crab to a private habitat. This will keep it safe during this vulnerable process.
Should I Dig Up My Hermit Crab?
In a word, no. Never force a hermit crab out of hiding. It will be buried under sand for a good reason. No positives will emerge from forcing the crustacean out of its submersion. Only do this is in a genuine emergency.
If you must dig around your hermit crab. Avoid any form of touching, prodding, or poking. Better yet, leave the hermit crab be. If it is buried under sand, you can still perform spot cleaning on aquarium walls.
You can tempt a hermit crab out of hiding. Place food in the corner of the aquarium. This will allow a nervous hermit crab to eat without exposing itself. Ensure the temperature and humidity levels are appropriate too.
The comfort of the hermit crab matters most. If it prefers to be underground, accept this. Even in the wild, some hermit crabs dig and burrow more than others.
Hermit crabs dig holes and hide for a range of reasons. Molting is the most common, but far from the only, explanation. If your hermit crab is staying underground, leave it alone. It will surface eventually, feeling better for it.