Are Hermit Crabs Born With Shells?

When I was a kid, I loved catching hermit crabs at the beach. I remember wondering if these little creatures came into the world with shells already attached to them or if they had to go find their own. Over time, I learned that the answer wasn’t as straightforward as I initially thought.

In this article, we’ll explore whether or not hermit crabs are born with shells, and we’ll look at some of the interesting facts about these fascinating creatures. Let’s dive in!

Hermit Crab Shells: What Are They?

Hermit crabs are unique creatures that have soft, vulnerable body that makes them vulnerable to predators. To protect themselves, hermit crabs find discarded mollusk shells, such as those belonging to snails, clams, and periwinkles, to use as a protective home.

These shells provide adequate space for the hermit crab’s body, and some species will even change shells as they grow in size. Hermit crabs are not able to create their shells, making it important for them to find the perfect fit. Without them, they have little protection against predators and other natural elements.

Interestingly, when a hermit crab outgrows a shell and needs to find a bigger one, they must go “shell shopping,” replacing the old one with a larger one while at the same time protecting their body from damage.

Do Hermit Crabs Hatch with Shells?

While some organisms like snails and turtles hatch with some form of housing or protective enclosure, hermit crabs don’t hatch with shells. Unlike other animal species that have protective shells, hermit crabs are born with soft, often translucent, shells that do not protect from predators or other dangers.

As the hermit crabs grow, they must search for and find shells for protection. Baby hermit crabs will even utilize small broken shells or other debris until they can find a more suitable home.

Hermit crabs often compete for a suitable fit, and it’s not uncommon for fights to break out over access to the best shells. Even when eliminated from shells or their homes, without adequate protection, hermit crabs face certain death. As such, shells are vital to helping the hermit crab survive and thrive, even from the very beginning of their lives.

Where do Hermit Crab Shells Come From?

Given that hermit crabs don’t hatch with any form of protection, one may wonder where exactly the shells come from. The answer itself is found in the ocean, where mollusks like snails, clams, and periwinkles roam. When these mollusks die or outgrow their protective shells, they leave the empty shells behind.

These shells can be found either on the ocean floor or washed up on shore. As such, hermit crabs must search, find and steal the ‘abandoned’ shells from other creatures to utilize as their own housing, making the competition for the perfect shell quite fierce.

Often, the most desirable shells go to the strongest and most aggressive hermit crabs. This is an interesting illustration of the ebb and flow of nature: one species may abandon something that, to another species, provides both a home and a layer of armor. In the end, the shells that protect and shield hermit crabs come from the natural cycles of marine life.

How Do Hermit Crabs Choose Their Shells?

Hermit crabs must choose shells that fit them perfectly. An unfitting shell could cause them harm, expose them to predators, and impact their mobility. The process by which they select the ideal shell involves them assessing multiple variables, such as the size of the shell, its weight, and its availability.

When hermit crabs search for shells, they are very deliberate in their movements, with searching, testing and moving through many shells until they find the right one. After finding what appears to be the appropriate shell, hermit crabs tend to go through a series of tests to ensure it is a suitable home.

These tests often include pushing themselves inside the shell to determine if it has the right shape and size. They may even try the shell on for size by walking and building to ensure that they have maximum mobility. A shell that satisfies their requirements will provide a safe haven from predators and the elements, allowing them to grow, mature and thrive.

When Hermit Crabs Outgrow Their Shells

As hermit crabs grow, they inevitably outgrow their shells, which they must replace with larger ones. They do so by going through a fascinating process known as molting. As a part of this process, the crab’s body will shed the older, smaller shell and go through a renewal stage where the new, larger shell begins to form, which can take several days.

The molting process leaves the hermit crab soft and vulnerable, and it is for this reason it will typically bury itself in the sand for several days as it awaits the new shell’s formation. Once the hermit crab completes the molting, it must find and maneuver into a larger shell.

However, since it still takes some time for the shell to harden, the hermit crab will remain hidden until the new shell is no longer vulnerable. Once the new shell is secure and solid, the hermit crab can resurface and continue with its daily activities, safe and well-protected once again.


In conclusion, hermit crabs are not born with shells, which leaves them incredibly vulnerable from the beginning. They must rely on scouring the ocean bed and shores for discarded mollusk shells, which they must then carefully evaluate and select based on a variety of factors to provide a good fit for the shells.

Once they find the right shell, they will live in it for the rest of their lives, unless they outgrow it, and then they must repeat the process. To thrive as a species, they must be able to find suitable shells that keep them well protected from the elements and predators.

The fascinating and complex process of selecting and maintaining shells, from their initial discovery to outgrowing them and molting, makes hermit crabs one of the most intriguing species found in the depths of our oceans.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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