Are Hermit Crabs Reptiles? Similarities and Differences

Hermit crabs are fascinating creatures that have piqued the curiosity of many exotic pet enthusiasts out there. Often kept as a pet, these small animals are known for their unique shell selection habits and their ability to adapt to many different environments. However, as with any type of pet, it’s important to understand the basics before diving in.

One question that frequently comes up is whether or not hermit crabs are reptiles. In this article, we’ll dive into the characteristics of both hermit crabs and reptiles to better understand whether or not these exciting pets are true members of the reptilian family.

Characteristics of Hermit Crabs

Hermit crabs are marine animals that are often kept as pets. They are members of the crustacean family and are known for having a soft abdomen that they protect by taking up residence in empty seashells. Hermit crabs love to crawl around and climb, and they have a wide range of behaviors that make them interesting pets to watch.

One unique characteristic of hermit crabs is their tendency to molt, which means shedding their outer exoskeleton. When a hermit crab molts, it is vulnerable to predators and can even appear to be dead, but as the new exoskeleton hardens, the crab can resume its normal activities.

Another interesting feature of these creatures is their shell selection habits. Hermit crabs need to find the right size shell that perfectly fits their body, and they will often spend hours looking for the perfect one. If they grow out of their current shell, they will need to find a new one or risk being unable to protect themselves.

Hermit crabs are also social animals and can be kept together as long as they are given enough room to move around in their enclosure. They are most active at night and enjoy a varied diet that includes everything from fruits and vegetables to protein-rich foods like insects and eggs.

Characteristics of Reptiles

Reptiles are a diverse group of animals that include snakes, lizards, turtles, and crocodiles. They are cold-blooded, which means that their internal temperature is influenced by the temperature of their environment. Most reptiles are covered in scales, which provide them with protection from predators and help with regulating their moisture levels.

One of the defining characteristics of reptiles is their ability to lay eggs with amniotic membranes, which helps protect the developing embryos from desiccation. Additionally, most reptiles have a three-chambered heart, unlike mammals which have a four-chambered heart.

Reptiles also have a unique respiratory system that involves breathing air into their lungs using a series of inhalations and exhalations. Unlike mammals, reptiles do not have a diaphragm, meaning they rely on their muscles to move air in and out of their lungs.

Hermit Crabs: Not Reptiles

Despite being categorized as marine animals, hermit crabs are not reptiles, but rather, are classified as members of the crustacean family. This distinction is due to a number of differences between these two groups of animals.

One of the most significant differences between hermit crabs and reptiles is their body structure. While reptiles have bodies that are covered in scales, hermit crabs have a soft abdomens that they protect by moving into empty seashells. Additionally, reptiles are vertebrates, meaning they have a backbone, while hermit crabs do not.

Another important distinction is that hermit crabs are cold-blooded, much like reptiles, but they have a more complex respiratory system that involves using gills for breathing in low-oxygen environments such as water, and a small pair of lungs for extracting oxygen from air.

Differences Between Hermit Crabs and Reptiles

While some people may think that hermit crabs and reptiles are similar due to their shared traits of being cold-blooded and having a hard outer covering, the two animals have fundamental differences that set them apart from one another.

Characteristic Hermit Crabs Reptiles
Body Structure Soft abdomen, protected by shells, exoskeleton instead of a backbone, no scales Rigid outer structure, backbone, scales
Respiratory System Gills to breathe in the water, lungs to breathe in air outside water Lungs for breathing
Habitat Preference Saltwater or freshwater environments A broader range of ecosystems, from deserts to forests to freshwater habitats

The body structure is one crucial difference between the two. Hermit crabs have a soft abdomen that they protect by residing in empty shells. They do not have scales for protection, and they do not have a backbone, but an exoskeleton. In contrast, reptiles have a more rigid outer structure that makes them more impervious to damage. They also have a backbone.

Another important distinction between hermit crabs and reptiles is their respiratory system. While reptiles rely on their lungs to breathe, hermit crabs have gills enabling them to breathe underwater, whereas they use their lungs to breathe in the air outside water. Hence, they cannot survive underwater as compared to reptiles.

Lastly, their habitat preference is also different, with hermit crabs often found in saltwater or freshwater environments, whereas reptiles can be found in a broader range of ecosystems, from deserts to forests to freshwater habitats.

Similarities Between Hermit Crabs and Reptiles

Despite the many differences between hermit crabs and reptiles, they do share some similarities.

Characteristic Hermit Crabs Reptiles
Cold-blooded Yes Yes
Respiratory System Have respiratory systems for breathing in oxygen Have respiratory systems for breathing in oxygen
Unique Exoskeletons Have unique exoskeletons that provide protection and help them adapt to their environment Have scales that protect them from injury
Popular in the Pet Trade Kept as low-maintenance pets in homes Kept as exotic pets for their intriguing appearances
Need Well-Maintained Living Conditions Require appropriate living requirements to ensure they remain healthy Require appropriate living requirements to ensure they remain healthy

For one, both groups of animals are cold-blooded, meaning that their body temperature is influenced by their environment rather than being regulated internally. Another shared characteristic is that they both have respiratory systems for breathing in oxygen.

Furthermore, hermit crabs and reptiles have unique exoskeletons that provide protection and help them adapt to their environment. While reptiles have scales that prevent them from being injured, hermit crabs take up inhabitance in empty shells for hull protection from predators.

Another similarity is that these animals are popular in the pet trade. Reptiles are often kept as exotic pets due to their intriguing appearances, while hermit crabs can be kept in homes as fascinating and low-maintenance pets, particularly for those with limited space.

Finally, both reptiles and hermit crabs need well-maintained living conditions to ensure they remain viable pets. A lack of appropriate living requirements, including temperature, and a lack of proper nutrition, can lead to health problems for both. Therefore, it’s essential to research and provide such requirements to ensure the longevity of each creature.

While hermit crabs and reptiles have many differences, there are also substantial similarities between the two, making them two remarkable groups of animals.

Common Misconceptions About Hermit Crabs

Hermit crabs are interesting creatures with many unique characteristics, and as with any animal, there are a few common misconceptions about them. Here are some of the most notable misconceptions surrounding these fascinating animals:

Misconception #1: Hermit crabs can live in small environments like plastic containers.

The truth is that hermit crabs require a larger space to thrive. People often buy small, plastic containers with limited or no ventilation and keep their hermit crabs in these inadequately ventilated environments. Hermit crabs need a spacious home to live comfortably, and such limited space can leach away the moisture and heat that they require to survive.

Misconception #2: Hermit crabs don’t need water or moisture.

Hermit crabs are crustaceans and require a humid environment to survive. Without moisture, they tend to develop shell rot and eventually get sick or die. They also require a source of fresh water to drink, and some even place shells filled with water in their habitats to mimic the seaside habitat.

Misconception #3: Hermit crabs can’t climb.

Hermit crabs are excellent climbers and need plenty of space in their enclosure to accommodate this activity. They have claws that enable them to climb trees, rocks, driftwood, and any other suitable elements within their habitat.

Misconception #4: Hermit crabs live their whole lives in one shell.

While hermit crabs are known for residing inside shells, they cannot live their entire lives in a single shell. Their bodies grow with time, implying they will eventually outgrow existing shells and have to seek a more extensive, appropriate home.


In conclusion, hermit crabs and reptiles share some similarities, but they are also fundamentally different. While both groups are cold-blooded, reptiles have a more rigid outer structure, a backbone, and rely on their lungs for breathing.

In contrast, hermit crabs have a soft abdomen, do not have a backbone, use gills to breathe in water in low oxygen environments, and lungs to breathe air outside water. Understanding these differences is essential when deciding whether to keep one of these animals as a pet and how to care for them properly.

Despite some common misconceptions about hermit crabs, they can make great pets with fascinating behavior. Although they are not reptiles, they still deserve a suitable environment, a source of fresh water, and varying nutrition to thrive. Proper research, care, and maintenance ensure their vitality and well-being in a household. Nevertheless, before adopting one of these creatures, always ensure you check with the law on acquiring and keeping animals in your region.

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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