Why Is My Hermit Crab Digging a Hole?

Sometimes it can be difficult to determine exactly why your pet is behaving in a certain way, particularly if the pet is a small land crab and can’t always effectively communicate its needs. There are several reasons why crabs may start digging holes. Knowing the reason for the behavior is the best way to take the appropriate steps to get your crab any extra care that may be necessary.

  1. Molting

    • In order to grow, a hermit crab must shed its exoskeleton in a process called molting. This process can take anywhere from several days to several months. During this time, a crab is very vulnerable to predators and it will dig a large hole to hide in.

      Crabs on the verge of molting spend most of their time sleeping or digging and tend to eat and drink more then usual. Their eyes may also appear cloudy and their skin ashy. If you suspect that your crab may be molting, give it with additional food and fresh water and remove other crabs from the tank. Hermit crabs are attracted to the smell of fresh exoskeleton and have been known to kill and eat the molting crabs.

    Food Storage

    • In the wild, hermit crabs occasionally bury food in the sand and attempt to retrieve it later. Unfortunately for the crab, it usually forgets the burial spot and will dig small holes trying to find it. Crabs digging holes for this reason will usually dig several small, shallow holes close together. Regular cleaning of the hermit crab cage should prevent this and keep the food it's trying to find from spoiling or molding.

    Dehydration

    • If you have a lot of crabs of different sizes in a small cage and don’t refill their water dishes as frequently as you should, some of your crabs may become dehydrated. Those crabs are digging holes in the substrate in an attempt to find moisture. Hermit crabs that are dehydrated will be less active then usual and have a musty smell.

    Boredom

    • Hermit crabs in the wild are sometimes referred to as “tree crabs” because they love to climb. If your hermit crab is restless, and appears to be active and healthy, boredom may be the reason that it is digging holes. Place a small piece of driftwood or object in the cage for it to climb on.

    Considerations

    • If you see small red or brown spots on your hermit crab and notice that your crab is lethargic and digging small holes to hide in, call your veterinarian immediately. Your crab may have mites, which are very contagious to other crabs and can cause death if not treated.