Why Do Hermit Crabs Dig? 4 Possible Reasons

Let’s say you are the new owner of your hermit crab and your crabs are already settling into their new home just fine, but then you notice new behavior that you’ve never seen before. Suddenly, the crab burrows into the substrate, disappears, making you wonder what’s really going on. Is this normal behavior? Should you be worried? Is there something wrong with your crab? These are all normal questions to ask, and by the end of this article, you will have the answers to these questions and more.


Is Digging Normal Behavior for Hermit Crab?

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When you are setting up your hermit crab cage, it is recommended that you use about 4 inches of substrate. Have you ever stopped to wonder why this happened? Hopefully, this isn’t a step you skipped, as your crabs desperately need that much substrate. All that substrate exists for one main reason: so your crabs can dig in it! Digging is a normal behavior that all hermit crabs exhibit from time to time. There’s absolutely no reason to worry if your crab is digging, but it may be an indication of something important.

4 Reasons Hermit Crab Hole

There are four main reasons why hermit crabs burrow. If you see your crabs digging, you should try to determine which of these reasons. Then, you can make adjustments if necessary.

1. Temperature Setting

One of the main reasons crabs burrow into their substrate is to help regulate its temperature. They can do this when it is too warm or too cold. When it’s too warm in the cage, your crab may start digging for cooler areas under the substrate. On the other hand, they can also dig to protect themselves when it gets too cold in the cage. Hermit crabs prefer a fixed temperature of 70-80 degrees Fahrenheit, so if the temperature is well below or above this, you may want to adjust to keep the temperature within this temperature range.

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2. Looking for Humidity

hermit crab digging

Hermit crabs need a moist, moist environment to thrive. They prefer humidity levels between 70%-80%, and if things get too dry, they tend to dig in search of moist areas underground. If you think crabs burrow for moisture, you’ll want to increase the humidity in their environment. This can be easily achieved with a few sprays from a spray bottle on the substrate and walls. Or, you can add a humidifier to the room where your crabs are kept.

3. Reduce Stress

Just like many animal species, crabs will hide when they are stressed or scared. If your crab is feeling stressed about something like a new habitat or a sudden change in temperature or light cycle, then they may be digging burrows as a way to make themselves feel safer.

4. change skin

hermit crab digging

Often, crabs need to molt their exoskeleton and allow a new one to form. During this time, crabs are especially vulnerable; it cannot move because it has no muscle control until the new exoskeleton hardens. During this process, your crab will eat its old exoskeleton to get calcium. But it must remain hidden from predators during this time, which is why the hermit crab will burrow into the soil to begin the molting process. If you notice that your crab is eating more than usual before digging, it is most likely molting.

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Should You Stop Hermit Crab From Digging?

hermit crab

Digging is a natural and often healthy process for hermit crabs. It can also be an indication of changes you should consider. Try to figure out why your crab is digging and then adjust. Make any necessary changes in temperature or humidity. But don’t try to stop your crabs from digging. Whatever the reason they are hiding, it is a natural behavior that you should not disturb. After all, your crab may have just molted, and you certainly don’t want to stop it.

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If your crabs suddenly dig, there are four main reasons behind it. They could be molting, stressed, too dry, or the wrong temperature. If you can adjust the crab’s environment and fix the problem, then do so. Otherwise, you should let the digging continue and try not to worry as this is a natural and harmless behavior.

Looking for more information about hermit crabs? See:

  • How Long Do Hermit Crabs Sleep?
  • How to Warm Hermit Crab Without a Heater (7 Different Ways)
  • How to Tell a Hermit Crab Type (with Pictures)

Featured Image Credit: SilvioFasler, Shutterstock