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Hermit crabs are fascinating creatures. Indeed, they are creatures that have a variety of habits that we as humans try to understand. One of these habits is their need to dig holes. One thing you should know is that digging is something that hermit crabs do naturally. They dig for a variety of reasons. Nevertheless, if you notice that your crab seems to be digging more than normal then it could be a sign that it is getting ready to molt. Here we’ll discuss a few of the reasons for digging in crabs.
It is important that your hermit crab’s tank is heated to the correct temperature. You should also provide a warm and a cooler side to allow your crab to move about should it get too hot or too cold. I recommend the warm side to be between 80F and 82F while the cooler side should be somewhere between 72F and 75F.
If the temperature in the tank gets too much higher than 85F, your crab is likely to become extremely uncomfortable and so might start digging down into the substrate as a way to de-stress. It is therefore particularly important that you monitor the temperature of the tank regularly. Invest in a good quality thermometer – these can be purchased at a local exotic pet store or online. Amazon sells a great selection, which you can see here if you’re interested (opens in a new tab)
As touched upon above, temperatures that are too high can cause a hermit crab to become stressed, so you are likely to see it digging as a result. But there are other things that can cause your crab stress. In fact, newly purchased hermit crabs are often stressed out by the time they reach their new home. The process of harvesting hermit crabs is tough on the creatures and many reach their new homes dehydrated and suffering from exhaustion. Digging is a natural way for hermit crabs to de-stress, so if your new pet is doing this then it is best to leave it be as it tries to get used to its new surroundings.
Preparing to Molt
Hermit crabs will molt as they grow and in the days before this occurs some start digging more than usual. Some hermit crabs bury themselves when they are about to shed their exoskeleton. It is best not to disturb a molting crab as you could end up harming it if you do. Once the outer shell has been shed, the new exoskeleton will need to harden; during this time, the crab will be extremely vulnerable. Just for your information, other signs of molting include lethargy, inactivity, and spending more time around the water dish.
Hermit Crabs Fighting Over a Shell Pagurus bernhardus Outside Shell
As you now know, hermit crabs dig for a variety of reasons, and most of the time it is nothing to be worried about. However, if stress is causing your hermit crab to dig more than usual, you will need to find the cause of the problem and correct it. Check the temperature of the tank to ensure it is within the correct levels.
In most cases, a digging crab should be left to its own devices and not disturbed. Nonetheless, if you are worried about this digging behavior and cannot find a cause, I recommend speaking to a vet for professional advice.
- Featured Image (Four Hermit Crabs): Drcbc – CC BY 3.0
- Hermit Crabs Fighting Over a Shell: Brocken Inaglory – CC BY 3.0
- Pagurus bernhardus Outside Shell: Arnstein Rønning – CC BY 3.0
- A Hermit Crab Emerging From Shell: U.S. Fish and Wildlife Service – public domain
- Dardanus calidus: H. Zell – CC BY 3.0
- Hermit Crab Retracted Into a Shell: Jerry Kirkhart – CC BY 2.0