Hermit Crab Articles

The body skeleton of a hermit crab is much different from that of mammals, reptiles, birds and fish. Their skeleton is on the exterior. It is called the exoskeleton. The exoskeleton is made of a material called chitin. It protects the crabs' organs from damage. The exoskeleton holds 90% of a hermit crabs calcium.

In order for a hermit crab to grow it must go through a process called molting. Just before molting, hermit crabs will drink a lot of water. This will increase their body weight by 25%. Sacs called Pericardial sacs fill with a mucus like substance that swells and splits the exoskeleton. The extra water is used by the hermit crabs circulatory system to increase the their body size (legs & claws) enabling them to regenerate any missing appendages.

Hermit crabs need two things to successfully molt and increase their size, water and calcium. Calcium is present in the shells and sand they eat. Since they lose 90% of their calcium when they shed their exoskeleton, they will eat their exoskeleton to regain it. Just before a female hermit crab molts her egg sac will swell. If she hasn’t successfully mated she will shed the egg sac along with her exoskeleton.

When your hermit crab does molt, it is important to leave them alone and keep the environment quiet. This is one of the benefits of having a hermit crab living separated. If your hermit crabs all live in one aquarium and you are not familiar with the signs of a hermit crab that is about to molt, your hermit crab can be in a lot of danger because of its vulnerable state.

Hermit Crab Molting Signs:

You notice they are drinking a lot more water than usual, so it is important you give them additional water and keep them moist by spraying their home (but don’t drench them).
They seem to grow lethargic and sleepy, they eventually have difficulty moving and should be left alone. They may stop moving altogether for a few days. (This is why a lot of hermit crab owners think their crab is dying/dead.)
They burrow into the sand, don’t dig them out.
Some hermit crabs go on an eating craze before a molt. Just let them eat, but remove all food when they molt.

After your hermit crab has molted, they will need time for their exoskeleton to harden. This takes almost 2 weeks to do. IT IS IMPORTANT to leave the exoskeleton. They need to eat this to regain the calcium lost in molting. I have noticed some of my crabs get very hungry after they have molted. It is a good idea to give them some food.