Hermit crabs got their name due to their reliance on shells. A shell provides essential protection for their soft abdomen, so hermit crabs will only leave their shells when they believe it’s safe.
The easiest way to get a hermit crab to leave its shell is by providing a superior shell. Alternatively, if you want to see your hermit crab or handle it, offer it a snack.
Don’t force a hermit crab to leave its shell against its will. Never 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.
Do Hermit Crabs Leave Their Shells?
Shells are important to hermit crabs, so they rarely leave them outright.
If hermit crabs don’t have a shell on their back, they have no protection from predators. Moreover, hermit crab shells are precious commodities, and a rival will soon claim an unguarded shell.
Hermit crabs will only leave their shells to molt, trade up for a better shell or cool off when the weather is excessively hot. In between, hermit crabs poke their head out of their shells occasionally to eat, exercise, or when they feel sufficiently curious.
Don’t worry if 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 to hold it because this will cause needless stress. The situations below are the only good reasons for ‘tempting’ hermit crabs out of their shells:
Happy and healthy hermit crabs will be active and playful for the day. If you never see your hermit crab move, it may be unwell. Common ailments worth checking include:
- Dull, gray coloring, although 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, as there’s no way of knowing if the illness is contagious. Left to recover in peace, the hermit crab may recover.
You may want to know the gender of a hermit crab out of curiosity, to choose a name, or because you have concerns about mating. If it’s the latter, don’t worry because hermit crabs rarely breed in captivity, so you can safely keep males and females in the same enclosure.
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 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.
According to the Marine Biological Association of the United Kingdom, you may have an intersex hermit crab with gonopores and a penis. However, the gonopores close with time, so they’re males.
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 pull the hermit crab out, you’ll remove 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 to be offered a better alternative. Many hermit crabs will upgrade their shell if something superior is available.
Collect new shells from a beachfront or order them online. If you take the latter approach, avoid painted shells, as paint can be toxic, and hermit crabs can get trapped inside.
Temporarily separate the hermit crab from its tank mates. 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 the shells in saltwater, as this makes them more appealing. As per Oecologia, hermit crabs prefer shells previously occupied by a conspecific.
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 aren’t sleeping or molting, they’ll emerge at some stage. If not, 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.
A distressed hermit crab should be left alone. Forcing them to interact against their will does more harm than good. The hermit crab will emerge when it feels sufficiently confident.
Long-term residents of an enclosure can also grow stressed. The explanation for this is trickier to identify, so look at what unfolds inside the enclosure. Common reasons for stress include:
- Unsanitary living conditions
- Bullying and aggression from conspecifics
- Unsuitable humidity
Find out why your hermit crabs are stressed and take steps to rectify it.
Fear of Losing Shell
As explained, shells are the most important thing to hermit crabs, which can lead to them coveting shells 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 hermit crab colliding with increasing force against the shell of another, which is a challenge for the shell.
It’ll emerge if the resident hermit crab wants to accept the challenge. Conflict will follow, although it rarely turns to outright aggression. If the occupant doesn’t want to risk losing its shell, it’ll stay inside. The hermit crab may also vibrate to warn the challenger off.
Hermit crabs are reluctant to leave their shells because exposure risks shell loss.
This means that hermit crabs eat, mate and defecate within their shells. Then, they flick any stored feces onto the substrate with their rearmost legs later.
Unwanted Mating Attention
Females may refuse to leave their shells if they receive unwanted male attention. Male hermit crabs can detect when a female is fertile, so they respond by guarding the female and fighting off other males.
The male will gently rock the female’s shell back and forth, which is an invitation to mate.
If the female is interested, she’ll emerge. If not, she’ll remain inside the shell. She’ll stay inside the shell 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, which can become problematic. The more a hermit crab grows, the tighter the shell will become.
Eventually, the hermit crab may get stuck in the shell. So, encourage the hermit crab to bathe in saltwater to loosen its grip. From there, entice it out with food.
Wet paint can trap hermit crabs in a shell, which is why avoiding painted shells is essential. Place the hermit crab in warm water to briefly bring water into the shell and turn the paint into a paste.
Take a paperclip and gently separate the hermit crab’s skin from the shell. Tempt the hermit crab out and throw the shell away, so it isn’t reused. Immediately provide several suitable unpainted alternatives.
How To Get A Shy Hermit Crab To Come Out
If hermit crabs are resistant to leaving their shells, you need to be patient, as there’s every chance your hermit crabs will emerge after dark. If you need a faster response, use these techniques:
Hermit crabs are shy animals, but they’re 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. However, this may also attract other hermit crabs, and nervous hermit crabs won’t be tempted.
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 is a favorite, as hermit crabs love sweet tastes and scents.
You’ll likely see the antenna twitch from outside the shell, which means the hermit crab is smelling the air. This will be followed by investigating the food.
Act quickly to do what you need to, as it may grab its snack and retreat.
Most hermit crabs will leave their shells if handled, which can be a strange sensation for hermit crabs. Hermit crabs poke their heads out of their shells to discover what’s happening.
This can be a good test regarding whether your hermit crabs trust you. Hermit crabs will emerge to smell your skin if you have a good relationship. If not, the hermit crabs will chirp and retreat into its shell.
In the latter case, be cautious, as hermit crabs can still pinch from within their shell. If hermit crabs have reason to fear for their safety, they’ll use their claws.
Turn Up The Heat
If you feel too warm, you’ll likely remove a layer of clothing. Hermit crabs follow the same protocol, so it’s common for hermit crabs to leave their shell when too hot.
This isn’t a sustainable long-term solution, as hot hermit crabs will be visibly uncomfortable. The reason hermit crabs are nocturnal is partially to avoid the heat of the sun.
Once your hermit crab leaves its shell, reduce the temperature. Most hermit crabs enjoy a temperature of 80 degrees Fahrenheit, but anything above 72 degrees Fahrenheit is safe.
Submersion in Water
Much like handling, water often brings hermit crabs out of their shell. Gently lift your hermit crab and place it in a body of saltwater.
Use this as a last resort. It usually works, but if it doesn’t, you place hermit crabs in jeopardy, as hermit crabs can drown. If hermit crabs hide due to fear or are stuck in their shell, they may remain within.
Minimize the risk of drowning by using shallow water with a nearby ramp to safety. Ordinarily, hermit crabs like to submerge in water; if unable to do so, they can’t drown.
Never force a hermit crab out of its shell, as they stay inside for their own reasons, unfathomable though they may be to us. Your hermit crab will emerge when ready.