Are Hermit Crabs Born With Shells?


by Simon Griffiths


The fact that hermit crabs are interesting animals will leave you with so many questions. Sometimes it’s even difficult to understand how these special crabs are born and how they develop to become normal hermit crabs.

People also tend to be inquisitive about hermit crab shells. Where do they get their shells from? Besides, are hermit crabs born with shells?


Are Hermit Crabs Born With Shells?

Absolutely not! Hermit crabs are not born with shells, they have to source the right-sized shells when they are mature enough to live outside the water. You’ll never see a hermit crab giving birth to juvenile crabs with shells.

As a matter of fact, hermit crabs have a long lifecycle and they have to pass through each stage in order to become true hermit crabs.

Now that you’ve figured out that hermit crabs are not born with shells, where do they get them from?

Where Do Hermit Crabs Get Their Shells?

Well, hermit crabs will rarely run out of shells to live in because Mother Nature is always generous.  Although they lack the ability to develop their own shells, they can use those shells that are abandoned on the ocean shores. Sometimes they will even steal shells from gastropods, snails, and other mollusks.

Once the crab identifies a nice shell, it will insert the abdomen through the shell opening and hold on to the columella (this is the central part of the shell). The crab will continue leaving in the new shell until it outgrows it.  As soon as the shell becomes small, the hermit crab will upgrade to a bigger “home” by scavenging for larger shells.

Related What To Do When Your Hermit Crab Leaves Its Shell

Do hermit crabs have to wait for the snails to die before stealing their shells? Unfortunately, these crabs can kill snails if there is a shortage of shells. As long as the crab has its eyes set on a particular shell, it will do anything to get it.

Surprisingly, stronger hermit crabs will even oust other crabs from their shells if they have to. When it comes to looking for shells, these little crabs do not joke about it. They would rather live in broken or small shells than live without one.

If an empty shell appears on the ocean shore, hermit crabs will line up and size themselves up from the largest to the smallest crab. They will then swap their shells until each one of them finds the right size for them.

Does this mean hermit crabs will always move from one shell to the other? Not really, some of them are not the mobile type and can live in a single shell without having to move.

Related How Do You Remove A Hermit Crab From Its Shell and Is It Safe?

Can Hermit Crabs Live Without a Shell?

Living without a shell is like a death sentence to hermit crabs. Their abdomen are so delicate that they have to protect it with the help of shells. If they leave their abdomens exposed, they’ll get burnt by the scorching sun and die.

Related How Long Can A Hermit Crab Live Without A Shell? 

Moreover, shells help these crabs to hide from predators. Hermit crabs will retreat their entire body to the shell if they sense danger.

Remember that these critters need to keep their salt levels regulated in order to function well. The only way to do that is by carrying some saltwater in their shells.

Shells play a huge role in the survival of hermit crabs. For instance, the shell can keep your crab safe when it is molting. A good shell will help to keep the substrate from compressing against the hermit crab’s delicate body.

Moving on, hermit crabs lay eggs in their shells so that they can stay protected from insects. You can imagine how important shells are to the lives of these crustaceans.

Sometimes these crabs will opt to use containers, coconut shells, and other fun stuff as shells. They don’t do it for fun, but to save their lives. So, if you come across a crab with no shell, be fast enough to provide one for them.

How Do Hermit Crabs Know They Need To Find A New Shell?

Hermit crabs are very intelligent pets, and they are fully aware of what is happening in their environment. These creatures can tell when their shells are becoming too small for them. In most cases, they will start shopping for new shells after a molt.

During this period, they’ll actively be searching for larger shells that accommodate their new bodies. This is why you have to provide your pet hermit crab with a couple of shells that are of different sizes.

These beautiful creatures will want to switch shells as soon as their current ones become crowded and uncomfortable for them to live in.

A study by Leah Valdes and Mark Laidre mentions that hermit crabs can smell the death of their fellow crab, and will flock together because there is an extra shell for the taking. All the swarming crabs will be in a frenzy to try and move into the leftover shell.

Related How Does A Hermit Crab Look Without A Shell

Wrapping Up

The topic of hermit crab shells is pretty wide, but I’ve done my best to answer your main question. As you’ve read above, hermit crabs are not born with shells, but they are experts when it comes to finding the perfect shells.

Remember that these shells have a purpose and you should never force your hermit crabs out of their shells. They should do it willingly instead of forcing them.

Simon Griffiths

Hi guys, my name is Simon, a fellow pet lover. I love everything about traditional and exotic pets so I am here to help you create a better home for your pets.