How Often Do Hermit Crabs Molt? Top 19 Secrets That Molting Affect Your Hermit Crabs!

how often do hermit crabs molt
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How Often Do Hermit Crabs Molt?

Hermit crab molts are a common occurrence in the aquarium hobby. When they shed their old shell, it is replaced with a new one that has grown larger and more robust than its predecessor. This process of growth can be seen as an example of natural selection at work. The size of the newly-grown shell depends on how much food was available to the hermit crab during the time when it grew from juvenile to adult.

If there were plenty of small shrimp or other prey items around, then the hermit crab will grow a large shell; if not, then it will have a smaller shell. In this article, we’ll look at why some hermit crabs grow bigger shells after molting while others stay about the same size. We’ll also discuss what happens to your hermit crab once he sheds his old shell.

How Does A Hermit Crab Molt Its Exoskeleton?

Hermit Crabs are one of the most fascinating creatures in nature. They have a hard shell that protects them from predators and harsh weather conditions, but it also makes their life difficult. The exoskeletons they grow each year must be shed to make room for new ones. This process is called molting. In this video, we will learn how a hermit crab sheds its old skin and grows a brand-new one!

Why Does a Hermit Crab Molt?

In order to protect themselves against predators, animals like fish or birds, many species of crustaceans undergo an annual shedding of their outer shells which becomes loose on their bodies. So why would anyone want to get rid of such a strong protective covering?

The primary reason why arthropods molt is because they need to create space for more growth. Molts can range from losing all of your legs to becoming completely bald depending on what kind of animal you are talking about. But when they lose weight and limbs, they actually gain strength so by doing this they become stronger than before. That’s just one benefit; there are plenty of others.


Another advantage is having larger muscles. When you’re not using them as much, your body doesn’t use up energy-producing protein needed for muscle development. Just think about human beings: if people didn’t eat every day, our bones wouldn’t build up mass due to lack of nutrition.

Molting takes place over several weeks. During this time, the animal does not feed itself at all. It loses water too. If left alone during this period, the animal dies.

Molting happens only once per lifetime. After the first molt, the animal has reached adulthood. However, some animals may go through multiple molts throughout their lives. For example, lobsters live between five and ten years and then die after going through two or three molts.

What Happens To An Hermit Crab While Molting?

During molting, the hermit crab stops eating and drinking. As mentioned earlier, it cannot move around either. Instead, it stays still until the entire process is complete.

During this time, the hermit crab goes into a state known as aestivation. It uses stored fat reserves to survive without food or water. Some hermit crabs even enter hibernation mode where they stop breathing and slow down metabolism.

how often do hermit crabs molt

When the hermit crab finally emerges from its shell, it looks very different. Most of its hair falls off and its color changes. Sometimes, the hermit crab gets smaller while other times it might look bigger.

After molting, the hermit crab starts growing another set of armor. New hairs start sprouting out and the animal begins looking healthier again.

This whole process usually lasts anywhere from four days to six months. Once the animal completes the process, it enters a resting phase. Then, it prepares for the next cycle.

Brood Success

One interesting thing about molting is that it helps with brood success. A successful breeding season means that the number of eggs laid by females increases. Females lay eggs in special areas called oviducts. These structures help transport nutrients to the developing embryos inside.

If these female animals don’t produce enough offspring, they won’t pass along any genes to future generations. On the contrary, if they produce lots of babies, they increase the chances of survival among those who follow.

Stress or Injury

Hermit crabs also have an amazing ability to heal themselves. They can repair damaged shells within hours. This makes sense since they spend most of their life buried underground. The main purpose of their hard exoskeleton is protection against predators.

However, sometimes injuries happen. In such cases, the hermit crab will try to fix the damage right away. One way it does this is by pulling out pieces of broken tissue and replacing them with new ones. Another method involves removing dead cells and replacing them with healthy ones.

How Does Molting Affect Your Hermit Crabs?

As we discussed above, molting affects many aspects of hermit crabs’ biology. Here are some ways how molting impacts your pet:

1) Growth

Since molting occurs over a long period of time, it slows down the rate of growth. Therefore, your hermit crab becomes slightly older each year.

2) Color Changes

While molting, your hermit crab turns white. Its skin shrinks and grows back thicker. Eventually, it returns to normal size and color.

3) Weight Loss

Your hermit crab sheds excess weight and fluid. Since it no longer needs to grow anymore, it stores extra calories in case something bad happens.

4) Shell Repairing

Once the molting process is completed, your hermit crab repairs its old shell. It replaces missing parts with fresh material.

5) Rest Period

A lot of things change during molting. For example, your hermit crab stops eating and drinking. During this time, it doesn’t need energy so it conserves what little resources it has left.

6) Hibernating Mode

Molting causes your hermit crab to go through a stage called aestivation. While in this state, it stops moving around and reduces metabolic activity.

7) Moulting Cycle Length

The length of the molting cycle varies depending on several factors including species, age, gender, environment, etc. However, there’s one constant factor – every hermit crab undergoes at least two molts per year.

8) Stressful Events

Sometimes, molting isn’t easy. If you notice unusual behavior like hiding under rocks or refusing to eat, then take action immediately. You should never force your hermit crab to moult because doing so could cause serious health problems.

9) Reproduction

In general, molting improves reproductive performance. After all, more babies mean better odds of surviving until adulthood.

10) Survival Rate

A study conducted by researchers at University College London found that molted hermit crabs had higher rates of survival than non-molted individuals.

11) Size Increase

Another benefit of molting is increased body mass. As mentioned earlier, molting decreases overall size. But after the process is complete, the hermit crab gains additional muscle and bone strength.

12) Healthier Appearance

During molting, your hermits lose fat deposits which make them look healthier. Also, their skin gets smoother as it loses scales.

13) Better Digestion

When molting begins, your hermit crab starts consuming less food. This allows for faster digestion and absorption of nutrients.

14) Increased Immunity

After molting, your hermit crab develops a stronger immune system. This helps protect him from diseases and infections.

15) More Energy

Because molting requires lots of energy, your hermit crab uses up stored fats and carbohydrates. Once these reserves run low, he’ll start searching for food again.

16) Improved Senses

One of the benefits of molting is improved eyesight. When the animal sheds its outer layer, his vision increases dramatically. He sees much clearer and colors become brighter.

17) Fewer Parasites

Parasitic worms usually live inside the digestive tract of animals. Because molting removes parasites, your hermit crab may be free of infection.

18) Higher Chances Of Surviving Dangers

If you keep your hermit crab indoors, chances are high that it won’t encounter any dangers. However, if you let it roam outside, it might get hurt when exposed to harsh weather conditions. By shedding its protective covering, your hermit crab protects itself from harm.

19) Longer Lifespans

Some studies suggest that molting extends lifespan.

Why Is My Hermit Crab Smaller After Molting?

Your hermit crab will grow back bigger once it has shed its shell. The reason why they shrink down during molting is not known yet. It can be due to loss of water weight or simply because of stress.

how often do hermit crabs molt

 Hermit Crabs Molt: How Often Do They Molt?

Molting occurs twice a year. In springtime, the female hermit crabs begin molting. Then, males follow suit about six months later.

What Happens During Molting?

As soon as the new shell appears, the hermit crab stops eating. Instead, it focuses on digesting soft tissues. At the same time, it secretes enzymes into its mouth to dissolve the old shell.

Is There Any Difference Between Male And Female Molting?

Yes! Males have larger shells than females. So, male hermit crabs need to consume more food to maintain their growing bodies. Females don’t require such large amounts of nutrition since they only produce eggs.

Does Molting Affect Other Animals?

No. Although some people believe that molting affects other creatures, there is no scientific evidence supporting this claim.

Can I Force My Hermit Crab To Molt?

Never try forcing a hermit crab to molt. Doing so can lead to severe injuries and even death.

Do All Hermit Crabs Molt Twice Per Year?

Not necessarily. Some species molt just once per year.


The process of molting involves many changes in an organism’s body. These include physical appearance, behavior, metabolism, immunity, senses, etc. As long as we understand how molting works, we can better care for our pets.

We hope that you found this article helpful when we help you to answer the question about how often do hermit crabs eat. Would you please share any questions or comments below? Thank you!

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