Hermit crabs spend more time upside down than many people realize.
Hermit crabs can sleep on their back, and they enjoy hanging upside from the roof of a habitat. A hermit crab on its back isn’t necessarily stuck.
Hermit crabs can get wedged between objects, especially if they have large shells. Also, a hermit crab may be dazed on its back after falling while climbing.
Hermit crabs can right themselves from an upside-down position if they have something to grab onto due to their strong legs.
Trust a hermit crab to right itself, at least initially. If it’s visibly distressed or hasn’t moved for some time, it may need your assistance with correcting its position.
Why is My Hermit Crab Lying Upside Down?
Lying upside down is a frequent position for hermit crabs in seafront gift stores. Shop owners flip hermit crabs on their backs as a sales technique, as they’re hoping the shell and claw will entice a customer.
If the hermit crab has been this way for a while, it will grow accustomed to this position. There is nothing inherently dangerous about it. Oftentimes, the hermit crab is completely comfortable this way.
All the same, this should not be a permanent position. By nature, hermit crabs are curious and investigative. A happy, healthy hermit crab will be keen to explore its terrain. If it never seems to move, especially at night, something may be amiss.
There are 5 core reasons for hermit crabs lying upside down. If you understand which applies, you’ll know whether to take action.
Hermit crabs lie on their back while molting. The likeliest explanation is that hermit crabs are vulnerable while molting. With no exoskeleton, they are easy pickings for predators. As we will discuss shortly, hermit crabs adopt an upside-down position to aid self-defense.
You are unlikely to see your hermit crab undertake this process. As hermit crabs feel unsafe while molting, they prefer to burrow for the duration. This offers a measure of privacy and protection.
All the same, if a hermit crab is on its back, consider if you recently observed the following:
- Constant digging
- Eating and drinking more than usual
- A glazed look in the eye
- Exoskeleton fading to a dull gray
If you answered yes to these questions, the hermit crab is likely molting. Consider gently relocating it to a private habitat until it completes the process. This will keep the hermit crab safe and secure.
Many hermit crabs grow anxious and uncertain in captivity. Human homes are filled with unfamiliar stimulation. This means they are likely to bury themselves. Some hermit crabs attempt to flee a tank, though.
A hermit crab hanging upside down from an aquarium roof is likely plotting an escape. This is attempted by pushing the lid of the tank with the legs. The limbs of a hermit crab are surprisingly powerful. If multiple hermit crabs team up, they may be successful.
If your hermit crab is constantly hanging upside down, consider why. If the hermit crab is contented, it may just be curious about the wider world as they like to explore and claim territory.
If the hermit crab shows other signs of unhappiness, it may be struggling with its habitat. You need to understand why this is. Common reasons for a hermit crab to seek new pastures include:
- Lack of space – you are housing it in an aquarium that’s too small
- Boredom – the hermit crab lacks company or stimulation in the habitat
- Inappropriate environment – the aquarium lacks sufficient heat, humidity, or light/dark contrast
- Difficulty breathing – it is suffocating due to toxins in the atmosphere
- Dull diet – as per Marine Ecology, hermit crabs appreciate a varied diet. If you feed the same food daily, it may wish to forage for an alternative
- Stress – the hermit crab may be miserable and anxious in captivity. Not all hermit crabs adjust to this lifestyle
It’s possible that you just have a Houdini hermit crab on your hands. If this is the case, take action to secure the enclosure lid. Weigh it down and prevent escape. Hermit crabs rarely last long outside an aquarium.
Fell While Climbing
The laws of gravity dictate that what goes up must come down. Hermit crabs are not immune to this. If your hermit crab does hang from an aquarium roof, it may have fallen. This is especially likely if the hermit crab fell asleep in this position.
Do hermit crabs sleep upside down? Some do. It all depends on its unique personality. Some hermit crabs find this position relaxing and comforting. Ergo, it stands to reason that they will doze off while hanging upside down.
As we will discuss shortly, hermit crabs are usually capable of righting themselves. This is not always the case, though. Some hermit crabs never learn how to flip themselves over. Also, the hermit crab may have been dazed from its fall.
It is not just hanging from a ceiling that could lead to such a tumble. As per the Journal of Crustacean Biology, hermit crabs are natural climbers. In the wild, they will seek shelter from the sun within the branches of a tree.
Many hermit crabs will embrace this instinct in captivity. Climbing opportunities can be a great recreational activity for pet hermit crabs. Leaving vines and obstacles will keep a hermit crab amused, especially if alone. It also provides privacy without burrowing.
It’s fine to encourage a hermit crab to climb. Be mindful of any falls, though. These can be fatal. Pad an aquarium floor with at least 4-6 inches of substrate to provide a cushioned landing. If you see your hermit crab drop and land on its back, ensure it is OK.
Hermit crabs sometimes flip onto their back as a defense mechanism. In theory, this act makes it harder for the hermit crab to evicted from a shell. In addition, it provides easy access to the large claw. This is the primary form of protection for a hermit crab.
You may see this behavior in multi-crab habitats. Hermit crabs, especially males, constantly battle over shells. Male hermit brands grow faster than females. This means they frequently molt and outgrow existing shells. A replacement will immediately be sought.
Proceedings of the Royal Society of London explains how a hermit crab fight begins with, “shell rapping.” This involves one hermit crab butting against the shell of another. The aggressor is intimating conflict. It is demanding a winner-takes-all confrontation for the shell.
Just as one hermit crab desires a shell, the current occupant has no interest in relinquishing it. This will result in the defensive hermit crab hiding. It could be knocked over by the shell rapping, though. In this instance, it will remain in this defensive pose.
Do not consider shell rapping a reason to keep hermit crabs alone. Despite these squabbles, hermit crabs are social. They do not enjoy living alone. This competition for homes is a fact of life for hermit crabs. Simply provide plenty of shell options for a colony.
We have the possibility that your hermit crab is trapped on its back. A hermit crab upside down in its shell may be wedged between two surfaces. Look closely to see if this is the case.
A hermit crab habitat should be packed with obstacles. These provide hiding places, climbing opportunities, and recreation. They can be a curse as much as a blessing, though. Hermit crabs have comparatively weak depth perception, especially when threatened.
A hermit crab will seek a hiding place if afraid. This could be just within the shell, but an additional layer of security will likely be sought. As explained by Behavioral Processes, hermit crabs can be intimidated by seemingly innocuous threats, including light.
The hermit crab may hide between a rock and aquarium wall, where it feels safer. As discussed, it may then flip over for additional security. This could see the hermit crab become wedged between an inanimate object and boundary. It did not judge the space well.
This should be an easy fix. Just move the object that is trapping the hermit crab. Wait for it to calm down first, though. If the hermit crab is still afraid, it will feel as though you are removing its sole source of security. It will likely pinch as a self-defense mechanism.
Can Hermit Crabs Right Themselves?
Hermit crabs can flip themselves over, but only if with help. A hermit crab needs to grab onto something for leverage. This is another reason why an aquarium should contain obstacles. They will keep a hermit crab upright.
If the hermit crab cannot right itself, another crab may lend a hand. Hermit crabs can work together to achieve a common goal. On the other hand, hermit crabs may sense weakness and attempt to assert dominance. Keep an eye on this.
If your hermit crab is not attempting to turn itself over, do not immediately intervene. It may be comfortable, sleeping, or destressing. It may also be catching its breath while dazed. If you’re keen to check if the hermit crab is able to flip itself over, make it worthwhile.
Food can often be a great motivator. Place some oats in the habitat. This will usually pique the interest of a hermit crab. Watch for any reaction. If the hermit crab flips itself over and eats, all is fine. If it wriggles its legs but remains on its back, it is struggling to right itself.
Turning a Hermit Crab Over
If a hermit crab on its back needs help, you must be delicate. Handling must be approached with caution. Never yank the hermit crab by the legs. You will likely end up tearing the legs clean off. They will grow back, but limit movement and cause no end of stress.
Place your hand in the substrate beneath the hermit crab. Be careful here – there may be another hermit crab burrowed beneath. If you disturb this crab, you will be pinched. Once you have the shell of the hermit crab in your palm, carefully lift it.
Slowly but surely, rotate the hermit crab. Start by moving it onto its side, then lay it flat in your hand. Do not shake the shell at any point. Do not attempt to drag the hermit crab out of its shell before flipping it over.
All being well, your hermit crab will immediately emerge from its shell once flipped over. You’ll see an antenna emerge, and the legs will stretch. Gently place the hermit crab back in its aquarium.
If the hermit crab does not emerge, try not to panic. It may be afraid after an ordeal. It is staying in its shell while it recovers. Alternatively, the hermit crab may be sleeping.
In this instance, consider temporarily rehoming the hermit crab is a solo habitat. This will allow it to recover from any stress involved by becoming stuck on its back. If the hermit crab still doesn’t emerge after a few days, start to investigate further.
Is My Upside Down Hermit Crab Dead?
Hermit crabs should not lie upside down indefinitely. It’s possible that your hermit crab is just molting. This process is often mistaken for a demise. It’s rare for a hermit crab to molt in plain sight, though. They prefer to burrow for this process. Signs that a hermit crab has passed away include:
- A strong smell of dead fish
- No response to any stimulus – blowing inside the shell or offering food
- Other hermit crabs gathering around their fallen comrade. Hermit crabs emit a pheromone to announce a vacant shell upon dying
Leave the hermit crab in a solitary habitat if you can. Hermit crabs are shy and can spend weeks or even months molting or destressing. Only assume the worst if there is no alternative explanation.
Hermit crabs can get stuck upside down. Oftentimes, this position will be adopted by choice. If your hermit crab is unable to right itself, though, it will appreciate your assistance. Do not leave it to struggle, especially if it looks visibly distressed.