Hermit crabs got their name due to their reliance on shells. A shell is an essential form of protection for their soft abdomen. This means that hermit crabs will only leave their shells if they think it’s safe to do so.
The easiest way to get a hermit crab to leave its shell is temptation. Make it worthwhile for your hermit crab to leave by providing an alternative, superior shell. Alternatively, if you want to see your hermit crab or handle it, offer it a snack. Your hermit crab will likely emerge to investigate what’s unfolding outside.
Never force a hermit crab to leave its shell against its will. Certainly, don’t attempt to pull a hermit crab out by force. It would rather lose limbs than its shell, so you’ll unintentionally pull off its legs. If your hermit crab is stubbornly determined to stay inside its shell, it will usually have a good reason for doing so.
Do Hermit Crabs Leave Their Shells?
Shells are really important to hermit crabs. Consequently, they rarely leave their shell outright. If hermit crabs don’t have a shell on their back, they have little protection from predators. What’s more, hermit crab shells are a precious commodity. A rival will soon claim any unguarded shell.
Hermit crabs will only leave their shells to molt, trade up to a better shell or cool off when the weather is too hot. In between, hermit crabs will poke their head out of their shells on occasion. This will happen when hermit crabs eat, exercise, or feel sufficiently curious.
Don’t worry if your hermit crabs never leave their shells. As nocturnal animals, they may only surface after dark.
Why Would You Need a Hermit Crab to Leave its Shell?
Don’t drag a hermit crab from its shell to show your friends or because you want to hold it. This will cause needless stress. The situations below are the only good reasons for ‘tempting’ hermit crabs out of their shell.
Happy and healthy hermit crabs will be active and playful at least some of the day. If you never see your hermit crab move, then it may be unwell. Common ailments worth checking include:
- Dull, gray coloring (though this also precedes molting)
- Infestations of mites
- Brittle limbs that look in danger of breaking off
- Signs of mold or fungi in the shell
If a hermit crab is sick, isolate it from its tankmates. There is no way of knowing if the illness is contagious. Left to recover in peace, the hermit crab may yet pull through.
You may want to know what sex your hermit crab falls under. This may be out of curiosity, to help choose a name or concerns over mating. If it’s the latter, don’t worry because hermit crabs rarely breed in captivity. You can safely keep males and females in the same enclosure.
Typically, you can tell if a hermit crab is male or female by its legs. The legs of males are hairy, while females have smoother legs. Once they do emerge, there’s a failsafe way to tell them apart.
Look above the third pair of legs on the hermit crab. If you see two small holes, known as the gonopores, it’s female. The sperm of the male is deposited into the gonopores during mating.
In rare cases, as per the Marine Biological Association of the United Kingdom, you may have an intersex hermit crab. These hermit crabs have gonopores and a penis. To all intents and purposes, intersex hermit crabs are males. The gonopores close with time.
Wrong Shell Choice
Sometimes, a hermit crab will insist upon remaining in a shell that’s no longer fit for purpose. This may be a shell that’s too small and restricts mobility. Alternatively, the shell may be cracked or broken.
Encourage hermit crabs to leave shells that have outlived their useful life. However, if you try to pull out the hermit crab, all you’ll do is pull off its legs. Make them believe they’re changing shells of their own volition.
How to Get a Hermit Crab to Change Shells
If you want your hermit crab to change shells, it needs an appropriate alternative. Many hermit crabs will upgrade their mobile home if something better comes along.
Temporarily separate the hermit crab from its tankmates. When one hermit crab changes shell, it sparks a trade among others. The Annual Review of Sociology calls this a vacancy chain. Also, a dominant hermit crab would demand the first refusal of a new shell.
Provide shells of varying shapes and sizes. Douse all these shells in saltwater as this makes them more appealing. As per Oecologia, hermit crabs also prefer shells that were previously occupied by a conspecific. Aim to provide shells that still smell of other hermit crabs.
Why Doesn’t My Hermit Crab Come Out?
What does it mean when your hermit crab won’t come out of its shell? Assuming that hermit crabs are not sleeping or molting, they will emerge at some stage. If not, something is amiss. Explanations include:
Stress and Anxiety
Some hermit crabs struggle with life in captivity, especially when you first bring a hermit crab home. Post-Purchase Syndrome, or PPS, is common in hermit crabs. The animals need to destress before they leave their shells.
A destressing hermit crab should be left alone. Forcing them to interact against their will does more harm than good. The hermit crabs will emerge when they feel confident enough to do so.
Long-term residents of an enclosure can also grow stressed. The explanation for this is trickier to pinpoint. Take a look at what unfolds inside an enclosure. Common reasons for hermit crab stress include:
- Unsanitary living conditions
- Bullying and aggression from other hermit crabs
- Unsuitable humidity in the habitat
- Lack of humidity in the enclosure
Find out why your hermit crabs are stressed and take steps to rectify it. Hermit crabs do not cope well with stress. They do not hide in shells to relax; they do so because they’re terrified.
Fear of Losing Shell
As explained, shells are the single most important thing to hermit crabs. This can lead to hermit crabs coveting vessels worn by tankmates. In such instances, the hermit crabs may attack each other to claim the prized shell.
Not all shell competition is aggressive. As per Proceedings of the Royal Society of London, sometimes it can take the form of shell rapping. Shell rapping involves one crab colliding, with increasing power, against the shell of another. This is a challenge for the shell.
If the resident hermit crab is prepared to accept the challenge, it will emerge. Conflict will then follow, though it rarely turns to outright violence. If the occupant does not wish to risk losing its shell, it will stay inside. The crab may also vibrate to warn the challenger off.
This makes hermit crabs reluctant to leave their shells. Any exposure risks loss. This means that hermit crabs eat, mate and defecate within their shells. They flick any stored feces onto the substrate with their rearmost legs at a later date.
Unwanted Mating Attention
Females may refuse to leave their shells if they are receiving unwanted male attention. Male hermit crabs can detect when a female is fertile. They respond to this by guarding the female, fighting off other males that may approach.
The male will also gently rock the female’s shell back and forth. This is an invitation to mate. If the female is interested, she will emerge. If not, she will remain inside the shell. She will stay inside until the male grows bored and moves on, which can take several days.
Stuck in Shell
Hermit crabs sometimes insist on remaining in shells that no longer fit. This can become problematic in the longer term. The more a hermit crab grows, the tighter the shell will become.
Eventually, the hermit crab may get stuck in the shell. At this stage, you have a problem. Encourage the hermit crab to bathe in saltwater. This should loosen the grip. From there, entice it out with food or an alternative.
Wet paint can trap hermit crabs in a shell, which is why it’s advisable to avoid painted shells. In this instance, place the hermit crab in warm water. This will bring water into the shell and turn the paint into a paste.
Take a paperclip or blunt knife and gently separate the hermit crab’s skin from the shell. Tempt the hermit crab out and throw the shell away so that it’s not reused. Immediately provide a suitable unpainted alternative.
How to Get a Shy Hermit Crab to Come Out
If hermit crabs are resistant to leaving their shells, be patient. There is every chance that your hermit crabs will emerge after dark. Set your alarm for the middle of the night, if necessary. If you need a faster response, use these techniques.
Hermit crabs are shy animals, but they’re animals that are governed by instinct. You can usually tempt hermit crabs out of their shells by promising rewards. As discussed, the promise of a new shell may do the trick. Just remember, this may also attract other hermit crabs. Nervous pets will stay put.
Food will be more effective. As per Behavior, the scent of food encourages hermit crabs to get mobile. Place a strong-smelling favored food within reach of the shell opening. Fresh fruit, sliced open, are common favorites. Hermit crabs love sweet tastes and scents.
You’ll likely see the antenna start to twitch from outside the shell. This means the hermit crab is smelling the air. This will be followed by investigating the food. Act quickly to do what you need to do. It may grab its snack and retreat.
Most hermit crabs will leave their shells if handled. This can be a strange sensation for hermit crabs. In some cases, it’s also an unwanted one. Hermit crabs poke their heads out of shells to discover what’s happening.
This can be a good test as to whether your hermit crabs trust you. Wait to see how your hermit crab reacts to handling. If you have a positive relationship, hermit crabs will emerge and smell your skin. If not, the hermit crabs will chirp and retreat firmly back into their shell.
In the latter case, be cautious. Hermit crabs can still pinch from within their shell. If hermit crabs have reason to fear for their safety, they will not hesitate to use claws.
Turn up the Heat
If you feel too warm, you’ll likely remove a layer of clothing. Hermit crabs follow the same protocol. It’s common for hermit crabs to leave their shell if too hot. Sometimes they’ll do so completely.
This is not a sustainable long-term solution. Hot hermit crabs will be visibly uncomfortable. The reason these animals are nocturnal is to avoid the heat of the sun. What’s more, hermit crabs quickly grow uneasy out of a shell.
Once your hermit crab leaves its shell, reduce the temperature again. Most hermit crabs enjoy a standard temperature of around 80 degrees Fahrenheit. Some prefer it cooler, though. Anything above 72 degrees Fahrenheit is deemed safe for hermit crabs.
Submersion in Water
Much like handling, the presence of water often brings hermit crabs out of their shell. Gently lift your hermit crab and place it in a body of saltwater. This water should be at the same temperature as the habitat.
Use this as a last resort. It usually works, but if it doesn’t, you are placing hermit crabs in jeopardy. If hermit crabs hide through stress or fear or are stuck in their shell, they may remain within. If this lasts longer than half an hour, the hermit crabs can drown.
Minimize the risk of this outcome by using shallow water. Ordinarily, hermit crabs like to fully submerge in water. If unable to do so, they cannot drown. Equally, this may not get results. The hermit crab sees little reward for emerging.
Never force a hermit crab out of its shell. Hermit crabs stay in their shells for their own reasons, unfathomable though they may be to humans. Your hermit crabs will emerge as and when they see fit.