People are often surprised to learn that Land Hermit Crabs engage in complex social behaviors, are capable of communicating via "chirps" and, with proper care, may live for over 20 years. As they have not yet been bred in captivity, Hermit Crab keeping also presents us with the opportunity to make discoveries that will advance our understanding of these fascinating creatures.
Coastal & Tropical Regions
The purple claw or Caribbean hermit crab, Coenobita clypeatus, is the species most commonly seen in the pet trade. It ranges throughout the Caribbean, reaching as far north as Florida and Bermuda.
Some populations live at altitudes of over 3,000 feet, but females return to the sea to spawn in a massive migration. The larvae float as plankton for 2 months before returning to land.
Hermit crabs utilize the discarded shells of other creatures as mobile shelters, and they must find larger shells as they grow.
Terrestrial hermit crabs are nocturnal, but pets often emerge to to feed by day. A reptile night light will allow you to observe them after dark. When established in a proper terrarium they will be very active and exhibit a wide range of behaviors.
Handling is very stressful to hermit crabs, even those well-adjusted to captivity. They can be grasped by the back of the shell, but they may be able to reach this area with their claws- large individuals can administer a painful pinch.
Setting up the Terrarium
A 10 gallon aquarium will accommodate 5-6 small crabs. Large, naturalistic terrariums will allow the crabs to exhibit a wider range of behaviors than will small enclosures.
Driftwood, coral, rocks, cholla wood, caves, and other furnishings can be used to facilitate climbing.
A molting tank should be set up if you have more than one crab. Hermit crabs are soft and defenseless after molting and can become a meal for their tankmates.
A mix of calcium sand and coconut fiber, both sold for use with reptiles, makes and ideal substrate. It should be deep enough to allow for burrowing and should be mixed with just enough water that it sticks together when squeezed.
Light, Heat & Humidity
Red or black reptile night bulbs will not disturb your crabs and so will allow you to watch them after dark. A day/night cycle of 12 hours each is ideal.
A temperature range of 75-80°F should be maintained. They will not survive long-term exposure to cool temperatures (70°F or below).
Incandescent bulbs, "regular" or red/black reptile night bulbs, can be used to heat the terrarium. Ceramic reptile heaters provide heat without light and so are useful at night. Reptile heat pads can be used below the terrarium, but these often do little to heat the air. All of these options will dry out the substrate, so it is important to monitor humidity.
Land Hermit Crabs possess unique gills that enable them to breathe air. Marine relatives extract oxygen from water. A humidity level of 70-80% is vital to your crabs' survival, as the gills must be kept moist in order to function. Drier conditions will lead to slow suffocation. A simple humidity meter should be used in all Land Hermit Crab terrariums.
Humidity can be increased by misting, adding water to the substrate. Coconut husk absorbs water well. Maintaining a shallow bowl of water and partially covering the terrarium's lid with plastic.
Hermit crabs are social animals, living and feeding in large groups. However, dominant individuals may prevent other crabs from feeding, and crabs that are molting must be isolated. A supply of empty shells of various sizes must be available.
Wild hermit crabs eat just about anything. Because of this, a varied diet high in calcium and other essential minerals must be provided or they will not thrive.
Often overlooked is their need for a bowl of marine water; salt mixes sold for use with marine fishes, not table salt, should be used. Soaking in sea water will provide the crabs with essential minerals not present in their food. Fresh water should also be available. Bowls should be filled only to ½ the height of the smallest crab and be easily-exited; Land Hermit Crabs will drown quickly if prevented from leaving water.
Commercial Hermit Crab food may be used, but only as a portion of the diet. The following foods should be included regularly: fresh shrimp and fish, various fruits and vegetables. Carrot may help in maintaining bright coloration. Hard boiled egg, chopped nuts and seeds, dry seaweed (sold as Nori and used in sushi preparation), oatmeal, tropical fish flakes, and a wide variety of freeze-dried foods marketed for marine fishes (prawn, krill, plankton, brine shrimp, etc.) are also beneficial options.
They also relish decaying wood and leaf litter; these should be collected from pesticide-free areas. Some individuals will eat their substrate as well. Reptile calcium sand is an excellent calcium source.
Cuttlebone bits and reptile calcium powder should be mixed into your crabs' food; whole cuttlebone should be available for "snacking".
Daily Care and Maintenance
Check your crabs daily for signs of an impending molt – digging, remaining below ground for long periods and/or listlessness are typical. Crabs about to molt should be isolated in a molting tank.
Salmonella bacteria, commonly present in reptile and amphibian digestive tracts, can cause severe illnesses in people. Handling an animal will not cause an infection, as the bacteria must be ingested. Salmonella infections are easy to avoid via the use of proper hygiene. Wash your hands with warm, soapy water before and after handling any animal. Please speak with your family doctor or veterinarian for more tips on preventing Salmonella, or please read our care guide Cleaning and Disinfecting Recommendations for additional instructions.
When it comes to your new pet, knowledge is the best way to choose an appropriate addition to your family. Learn as much as you can about your new friend before you bring him home to ensure your pet enjoys a long, healthy life.
If you have any questions or concerns, please contact our reptile room at 717-299-5691 ext. 1240 or email@example.com.