Shedding an exoskeleton is just a natural part of the crab’s life. They need to shed their old shells in order to enlarge and fit a new one.
When a hermit crab sheds its shell it can become vulnerable. Other hermit crabs may want to evict it and take over its home.
Natural Shells
A hermit crab needs to find a shell that fits so it can shelter itself from external elements like heat and the sun’s UV rays. Hermit crabs also need a shell to protect their soft inner bodies from bacteria and other contaminants that can cause diseases or death. While there are customized glass shells that can be bought from pet stores or crab kiosks, they come with a high price tag and do not offer the same benefits as natural shells. Natural shells are made by marine gastropods and are spiral in shape. These shells form over time as calcium carbonate deposits build up until they create a crystalline structure that is held together by thin membranes of organic material. These shells provide the hermit crab with a home, protection, and a way to regulate their humidity level (reference).
When a hermit crab is interested in a new shell it will begin by sniffing the area around the opening of the shell. He will then use his claw to reach inside the shell and ensure that it is a good fit. If he does not find any debris or other critters inside the shell he will take it over and move in. If he notices another hermit crab in the shell he will usually try to evict the other hermit crab and will fight if necessary. This can be dangerous for the hermit crabs as they could lose limbs or die during the eviction process.
In addition to the size of the shell, hermit crabs are also concerned with the shape of the opening and the type of shell. The shape of the shell opening can be round, oval, or D-shaped and there seems to be a preference among hermit crabs for certain shapes. It is important to provide a variety of different shaped shells so that your hermit crab has many options available.
Shells that have been painted or coated with sealers are not considered to be a good option for hermit crabs as they may contain toxic chemicals that can be harmful to the crabs. In addition, the paint and sealer can interfere with the shell’s ability to regulate humidity and it may also change the feel of the shell, weight, and shape.
Conch Shells
Hermit crabs without shells rely on other forms of protection. Some species grow hard plates on their exoskeletons, while others use camouflage as a means of defense by blending into their surroundings and making it more difficult for predators to spot them. Regardless of their methods, these hermit crabs are just as unique as their shelled cousins.
In the wild, hermit crabs scavenge for their homes. They are always looking for a shell that is the right size, has sturdy walls, and holds enough moisture to protect them from predators. Hermit crabs will also switch their shells several times throughout their lives as they outgrow them or want to upgrade. Providing hermit crabs with a variety of shells is important for their health and happiness.
Most hermit crabs prefer ocean mollusk shells, but the specific types of shells they choose to wear depend on their geographic location. In Florida and the Caribbean, hermit crabs are commonly seen wearing whelk and conch shells. Hermit crabs found in the Pacific Northwest and Australia are more likely to be seen wearing periwinkle shells. Other hermit crabs may even wear the shell of a land snail such as an apple snail.
If the ideal shell isn’t available in their immediate area, hermit crabs will travel long distances to find it. They will often be able to tell a good shell from a bad one by the shape of its opening, which must match their body perfectly for hermit crabs to move inside. Once they find a shell that meets their criteria, they will immediately move into it. Hermit crabs are known to engage in “housing wars” over their favorite shells, so it’s important that the right types of shells are regularly available in a pet store or crab kiosk.
Choosing natural shells is always the best option, and it’s usually better to avoid painted shells that have been sold at pet stores or hermit crab kiosks. While these shells look cute, the paint and sealer can change the weight, feel, and shape of the shell, as well as interfere with its ability to regulate humidity inside. In addition, the chemicals used in paint and sealer can be toxic to hermit crabs.
PVC Pipes
Hermit crabs have a soft inner body that is vulnerable and needs to be protected. Their squishy bodies are not hard like their outer exoskeleton, so they have learned over the course of evolution to use shells or other objects that look like shells for protection. They can also use other items that help insulate their bodies, like rocks or plants.
When a hermit crab is sick or molting, it may not be able to find a suitable shell. They will then seek out other items that can act as a shell. These items include things that will insulate their bodies, like a coconut hut or an aquarium bubble cage.
These items can help protect hermit crabs from parasites, bacteria and other harmful pathogens. However, a hermit crab without its shell is vulnerable to infection and should be taken to a pet store or veterinarian as soon as possible.
A hermit crab can also use a PVC pipe in its habitat as a temporary shell. This is an option that is safe for hermit crabs because it doesn’t have any holes or other dangerous features. However, it is not recommended for permanent shells because hermit crabs need to be able to fit inside their shells, and the PVC pipes are much bigger than hermit crabs’ typical shells.
Some pet stores sell high-quality natural shells that can be decorated to make them look more attractive to hermit crabs. These are good options if you want to give your hermit crab a beautiful home, but these shells can be expensive. Some pet stores sell cheap plastic shells for hermit crabs that are less expensive, but they aren’t as sturdy as natural shells and can be broken easily.
Hermit crabs are highly social animals and prefer to live in groups of at least three. They can become stressed when they are isolated, so a group can help keep hermit crabs healthy and happy. If you have a solitary hermit crab, be sure to provide plenty of hiding spaces in its enclosure, such as rocks, driftwood, logs, coconut shells and PVC pipes.
Man-Made Shelters
For the most part, hermit crabs are quite picky when it comes to housing. They protect their soft abdomens by inhabiting empty snail shells that they have scavenged from the ocean floor or tidal pools, and they must search for new dwellings regularly as they grow bigger. In the wild, they may also engage in house-hunting “wars,” in which they will occupy a shell that fits them well until another crab tries to claim it and then exchange it for one of higher livability quotient.
Because of the hermit crabs’ reliance on empty shells for shelter, biologists are concerned that overfishing and pollution are contributing to the animals’ lack of adequate housing in their natural habitats. In addition, shells that are not properly cleaned can be home to unwanted bacterial growth. To combat the hermit crab’s housing crisis, scientists have developed man-made structures that mimic a shell and can be used as a home for these crabs.
Sculptor Aki Inomata has designed tiny homes modeled after skyscrapers, windmills and churches for hermit crabs without shells. She is also concerned with the crabs’ need for proper livability, so she has employed CT scanning to ensure that her designs would be acceptable to her occupants.
She has come up with a number of innovative ideas for constructing hermit crab houses, including the use of PVC pipes. These are lightweight, offer solid protection and have only one opening, making them harder for predators to attack from multiple angles. While they can be a good alternative to natural shells, they do not have the aesthetic appeal that a hermit crab craves.
Another popular option for a hermit crab’s shelter is a plastic critter carrier, which can be purchased from many pet stores or online. This type of container is ideal for hermit crabs because it provides a comfortable space for them to live and allows them to be moved around easily. In addition, if you have some sphagnum moss that was not sprayed with pesticides and is damp, this makes a great temporary bedding material and can help to keep the humidity up in the crabitat.