How Big Do Hermit Crabs Get? Complete Size Guide And Facts For Kids

Did you know there are more than 800 species of hermit crabs?

These beautiful creatures are known for the elegant mollusk shells that they turn into a home. Mainly there are two types of hermit crabs, one is the ocean hermit crab, while the other is the land hermit crab.

The soft-bodied look of these crustaceans often makes you feel that it's a lobster rather than a crab, which isn't true, but it is closer to the former animal. These omnivorous crabs spend a lot of time in old shells that are widely available near the ocean as they have vulnerable bodies. Because of their attractive nature and harmless personality, hermit crabs have become common pets for people. Even though most people know that they come in different sizes, they are still unaware of how much these crabs can grow. So, to help you out in discovering about the hermit crabs, we have curated this article specially for you!

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How big do hermit crabs get compared to other crabs?

One of the first things you should realize about hermit crabs is that it lives in borrowed shells or other crevices. You need to measure a hermit crab without a shell to get its true size. Most species of hermit crabs grow to the size of 0.5-4 in (1.2-10 cm). So, even though the hermit crabs may look enormous due to their large shells, they are mostly tiny creatures. Compared to the usual hermit crabs, a Dungeness crab manages to reach an average size of 6-7 in (15-17.7 cm), while snow crabs grow until they are 3-6 in (7.6-15 cm).

The most commonly found species, the Caribbean hermit crab (Coenobita clypeatus), grows to a size of up to 6 in (15 cm), making it bigger compared to the other species in the wild. At the same time, the long-armed hermit crabs measure up to 0.5 in (1.2 cm). However, the largest species has to be the coconut hermit crab, a land hermit crab with a leg span of up to 40 in (101 cm) along with a weight of up to 10 lb (4.5 kg). It gets the name from the ability to crack open a coconut with its pincers. The Ecuadorian hermit crab is often kept as a pet and is easily available in a local pet shop. These grow to a size of 0.4 in (1 cm) and are often the smallest hermit crab species.

How does captivity affect the size of a hermit crab?

When the crabs live in their native wild habitat, there's a lot of space they can explore. When you keep it as a pet, the hermit crab is most likely to remain in an aquarium. So, it's quite important to know if this can affect the size of the animal. Hermit crabs molt to form a new exoskeleton. As it doesn't get enough space to grow in the tank, the crab can shrink in size or stop growing to its fullest potential.

It's a raging debate in the pet world if people at all should have access to hermit crabs as pets. Those crabs that are purchased from a pet store or a souvenir shop by the sea don't last very long. One of the primary and major reasons behind this is that people breed the crabs in captivity. So, the animal fails to live up to its potential life. Another factor that can affect the hermit crab size, is the size of the shell available to it. If you have a pet, try to use bigger hermit crab shells so that the animals can grow. Also, make sure to give it adequate food, especially during the molting period, for ultimate hermit crab nutrition.

What is an ideal tank size for a hermit crab?

The ideal hermit crab tank size is based on the size of the species. So, if you have the Caribbean hermit crab (Coenobita clypeatus), you'll naturally require a bigger tank size compared to someone who has an Ecuadorian hermit crab. In general, a tank size of 5 gal (22.73 l) is best for keeping two hermit crab members.

One of the things that people fail to realize is that hermit crabs are social creatures. Yes, the animals do have a tendency to crawl into their shells, but all the species of hermit crabs are social animals, and the crabs interact with each other. Whenever you think about getting hermit crabs, try to bring as many members as possible. Along with that, you have to take care of their shell. It shouldn't be too small, or it will restrict the crab's growth. Also, make sure to give the crabs enough options of shells for them to be more relaxed in their new tank home. If you can, try to make an environment in a 10 gal (45.46 l) tank that can hold about 3-5 crabs comfortably.

Are hermit crabs a good pet?

When we think about hermit crabs as a pet, yes, these animals are sweet and non-harmful to humans, so it's considered a good pet. In recent years, the trade for hermit crabs has been rising for land hermit crabs as well as marine hermit crabs. However, as a crustacean, it isn't likely to recognize its owner.

Having said that, people often oversee that these animals require a special environment to be raised. This includes having a tank that has access to the right humidity and temperature as it's a tropical animal. Moreover, a hermit crab shouldn't come in touch with tap water because it is bad for the bodies of these crabs. Another issue is that hermit crabs can live for a long time. Even though 10-30 years is more common, species like Coenobita brevimanus can live for up to 70 years. Hence, it will be on you to take care of this pet and never release it in the wild as it cannot fend for itself. Unfortunately, most hermit crabs that make it to a house as a pet, live for 1-2 years. The crabs mostly die because of stress on their gills and other parts of the body.

These animals also require enough space for the process called molting. Without having a proper molt, the exoskeleton can be underdeveloped, and the crabs can be left even more vulnerable. Apart from big shells, the area should also have a sand substrate and enough rocks. The sand also helps in burrowing during molting. When providing the shell, look at its shape to make sure that it's fit to be housing for the crab. Additionally, the food and water bowls given to the hermit crab should be free from metal.

One of the other tips we can give you is to avoid wild-caught, land hermit crabs, or other hermit crabs that are sold as pets, usually in a seaside store where they breed these crabs for profit. When setting up a tank for this animal, make sure to use fresh dechlorinated salt water so that the crabs can thrive and live a happy life. Another thing to avoid at all costs is calcium carbonate in water, this can stick to the body or gills and restrict the movement of the crabs.

When it comes to food, the hermit crab's menu includes vegetables and fruits that these crabs can eat at night, one of their beloved foods is kale. Some hermit crabs also like to eat fish pellets too. Make sure to provide it with fresh water along with the food, and remove any leftover food in the morning to keep the water clean.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for how big do hermit crabs get then why not take a look at how do birds find worms, or how do dolphins sle