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Interesting Hermit Crab Adaptations

Interesting Hermit Crab Adaptations

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The purpose of this blog is to share general information and is written to the author's best knowledge. It is not intended to be used in place of veterinary advice. For health concerns, please seek proper veterinary care. In addition, as an Amazon Associate I earn from qualifying purchases.

If you own a hermit crab as a pet, you likely know that they’re really interesting creatures. These crabs are starting to become more common these days.

People think they’re neat because of how they look. It can also be a lot of fun to observe them.

If you don’t know a lot of technical information about hermit crabs, you might want to learn. For example, you might be interested in learning about hermit crab adaptations.

What are the hermit crab adaptations that you need to know about? Below, you’ll learn all about this topic as well as other pertinent hermit crab facts.

Hermit Crabs Have Soft Bodies

The first thing to know is that hermit crabs have very soft bodies. Since they have such soft bodies, they rely on shells for protection.

Hermit crabs find shells on the shore that they will then live in. As hermit crabs grow, they will need to find new shells that are a better fit for their current size.

These creatures will change shells many times throughout their lives. They go through periods of molting and growth.

It’s not unusual for hermit crabs to trade shells either. They truly are very interesting creatures.

Hermit crabs are able to live inside of these shells because they possess a hook-shaped tail. They also have powerful legs that are capable of hanging onto the inside of the shell.

It’s remarkable how well the hermit crabs are able to get around while living inside of shells. The shells aren’t a part of them, but they’ve adapted to learn how to use them to make up for their soft bodies.

Hermit Crabs Can Fully Retreat Inside Their Shells

You’ll find that hermit crabs are always going to pick shells that they can fully retreat inside of. There will be times when hermit crabs will encounter threats in the wild.

If a predator approaches a hermit crab, it’ll be able to hide inside its shell. This can help the hermit crab to survive an attack in many instances.

It doesn’t guarantee that the predator won’t force the hermit crab out of the shell, though. The shell simply provides a level of protection, and the predator might give up and look for easier prey.

If hermit crabs didn’t have these shells to rely on, they’d be easily killed by predators. Their soft bodies cannot survive attacks.

How Hermit Crabs Change Shells

As noted early, hermit crabs are going to grow out of their shells eventually. A hermit crab will eventually grow too large for its current shell.

When the time is right, the hermit crab will search for a new shell that it can utilize. Once it has found a shell that is the right size, it’ll act quickly to seize it.

The hermit crab will run out of its current shell and try to scurry as fast as it can. It’ll seize the new shell and get inside so that it can be safe once more.

As you’d expect, the hermit crab will feel very vulnerable when it isn’t inside of a shell. It doesn’t want to take too long to run to the new shell or it’ll put itself in great danger.

Hermit Crabs Are Omnivorous Scavengers

Hermit crabs are omnivores that scavenge for food out in the wild. They usually wind up eating whatever they can find, and often that winds up being dead fish or animals.

You’ll find hermit crabs combing the area looking for things that they can eat. They certainly will eat plants when they need to as well.

Some people refer to hermit crabs as a natural cleanup crew. They go around scavenging and eating dead things to clean the area.

They can’t afford to be picky about what they eat. Since they will eat just about anything that they can, it’s easy to feed hermit crabs when keeping them as pets as well.


Molting is something that hermit crabs have to do every so often. This process is very stressful for hermit crabs and it can be dangerous as well.

Essentially, a hermit crab’s body is going to outgrow its exoskeleton. The exoskeleton must be shed for the hermit crab to keep growing and moving forward in life.

When hermit crabs are in a juvenile state, they will molt more often since they’re growing rapidly. Once hermit crabs reach adulthood, molting will be less frequent.

On average, an adult hermit crab will molt every 18 months. If you have a hermit crab as a pet, you’ll need to protect it during this time.

Hermit crabs can die if they become startled while molting. They dig into the ground and you might worry whether the hermit crab has died or not.

You’re not meant to disturb it during this time. It’s also important to try to keep the other hermit crabs from bothering the molting hermit crab.

Hermit Crabs Are Hard to Breed in Captivity

You might not know this, but most hermit crabs that are sold in pet stores have been captured in the wild. This is because hermit crabs are decidedly hard to breed in captivity.

Some people have managed to find success breeding hermit crabs, but most don’t. There is such a demand for hermit crabs as pets that there are many people who capture wild hermit crabs for sale.

Of course, there are a number of people who are against keeping hermit crabs as pets. Many organizations say that keeping hermit crabs as pets is morally wrong.

Whether hermit crabs should be kept as pets or not, it’s true that most of the hermit crabs you’ll find for sale were once wild. If you buy hermit crabs for your home, you’ll likely not be able to get them to breed.

Plastic Pollution

Another interesting fact is that hermit crabs are having many problems finding shells in modern times. Pollution has made it difficult for hermit crabs to find what they need.

Sometimes appropriate shells are harder to come by than they should be. It’s also true that many crabs get confused and think that plastic bottles might make good shells.

Plastic pollution is a big problem around the world. Many beaches are littered with plastic, and plastic bottles or containers can wind up killing many animals.

A hermit crab might mistake a plastic container or some type of bottle cap as a shell that they can utilize. It’s a sad reminder to try to do your part to limit plastic pollution.

Crabs can become trapped inside of plastic containers rather easily. They won’t be able to get around and they will die.

This leads to another interesting thing happening that is rather unfortunate. When hermit crabs die, they release pheromone signals to other hermit crabs in the area.

The pheromones indicate that another shell has become available for use. This could lure another hermit crab into a trap and perpetuate a cycle of plastic bottles trapping and killing hermit crabs.

Should Hermit Crabs Be Kept as Pets?

Whether hermit crabs should be kept as pets or not is a divisive subject. You can decide for yourself whether keeping them as pets is right or not.

They can make good pets for people depending on what they want. If you want a pet that you can interact with, you’ll be disappointed by keeping a pet hermit crab.

Hermit crabs don’t socially interact with humans. These are pets that you will simply care for and observe.

They can be rather interesting to watch since they have unique personalities. It’s also notable that these creatures do best when kept in groups.

If you want to buy a hermit crab as a pet, you should buy at least two of them. This will ensure that they will do well under your care.

They’re easy to care for and don’t require a lot of maintenance. You just need to feed them every so often and keep the habitat clean to keep things from smelling bad.

You also must keep an eye on the humidity levels to prevent the hermit crabs from having breathing issues. Hermit crabs need to have their gills stay moist to be able to breathe normally.

As such, it might be appropriate to have a humidifier of some sort near the habitat. You should measure the humidity regularly to monitor the situation.

Final Thoughts

Hermit crabs are fascinating creatures that you now know a bit more about. You’ve learned a bit about these crabs and how they’ve adapted physically.

They use shells to protect themselves due to having soft bodies. It’s possible for them to use shells due to having hook-shaped tails and powerful legs that can grip the shells.

Hermit crabs are omnivorous scavengers that will go around eating what they can. They’ll eat plants, but they will also eat dead fish and animals.

Plastic pollution is a real threat to hermit crabs. They often get tricked by plastic containers and think that they’re shells.

Keeping hermit crabs as pets is popular, but since they don’t often breed in captivity most of the hermit crabs being sold are from the wild. Remember all of these bits of information about hermit crabs and tell your friends if they’d like to learn more about these creatures.

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