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Why Turtles Can’t Live Without A Shell

Can turtles live without a shell?

No, turtles cannot live without a shell. Why you ask? While there are several reasons, the main one is that the shell is an integral part of a chelonian’s body. The shell holds and protects all that inside the turtle including the internal organs. The shell protects the turtle. Even the ribs of the turtle are part of the shell. The shell can also feel.

The only parts of the turtle that aren’t protected by the shell at all times are the limbs, neck, head, and tail.

See our article about the inside of a turtle shell for a complete breakdown of everything inside it.

Why is a shell necessary to a turtle’s survival?

empty box turtle shell
empty box turtle shell

It is easy to imagine the shell as the housing of the turtle similar to how hermit crabs use shells as housing. But that’s not the case here.

The shell serves as armor and protects the chelonian

Insides of a turtle shell
Anatomy of a turtles insides

The turtle’s shell protects the turtle. Turtles aren’t quick generally speaking, though there are some “fast turtles” out there. Their movement speeds make the shell an essential part of their body and lifestyle. The turtle’s suit of armor (its shell) is hard to crack. This protects them from a wide variety of predators.

It is common to find evidence of attacks on the shells of wild turtles. These include claw and bite marks. These are testimonies of the effectiveness of the carapace and plastron.

florida box turtle closed inside its shell
florida box turtle closed inside its shell

Most turtles can retract into their shells for protection. They can tuck in their heads and limbs. Some even go a step further. Turtles such as box turtles have hinged plastron, which allows them to completely enclose themselves in their shell.

Not all turtles can retract into their shells. Even with these turtles, the shell still offers protection. Sea turtles cannot retract into their shell but it does help protect them from predation as evident by the bite marks usually found on the shell of adult marine turtles.

The shells (in particular the carapace) of most small turtles are also camouflaged. The coloration, as well as markings on the shell, helps the turtle to blend in with its environment.

Also just as our skin protects us from the many harmful microbes in our environment, the turtle’s shell also protects them from disease-causing microbes such as bacteria, viruses, and fungus.

The shell is part of the chelonian’s skeleton

Painted turtle on log pulled back into its shell
Painted turtle on log pulled back into its shell

The shell isn’t just a casing in which the turtle is, it is part of their skeletal system. So a part of a turtle’s skeleton is the shell. Even the ribcage of the turtle is fused to the skeleton. So are the spine and spinal cord.

In fact, the plastron can be said to serve a similar function to that of inscriptional ribs in crocodiles and the sternum and clavicles in other four-limbed vertebrates.

The ribcage of the turtle is connected to the shell. In fact, you can say that this forms part of the turtle shell. The shoulder blades also connect to the shell. All the limbs of the turtle connect to the shell.

To summarize, the shell is connected to the rib cage, spine, and several other bones in the turtle’s body. one thing the turtle cannot live without is the shell.

The shell is part of the chelonian’s skin

Not only is the shell part of the turtle’s skeleton, but it is also part of the turtle’s skin. With softshell turtles and leatherback turtles, it is easy to see that the shell is part of the turtle’s skin as their shells feel leathery and tough.

spiny softshell turtle (apalone spinifera)
spiny softshell turtle (apalone spinifera)

These softshell turtles have tough skin on the outer part of their shells. What about turtles with hard shells? Even these have shells with skin (scientifically known as dermal plates).

The turtles’ shell is made of dermal plates as well as endochondral bones. As the chelonian matures, the dermal plates ossify and become harder.

Atop of these dermal plates are the scutes. The scutes protect the dermal plates and all that’s beneath. Not all turtles have scutes. For instance, softshell turtles do not have scutes.

Aquatic turtles usually shed their scutes for new ones. Tortoises on the other hand add rings to their scutes.

What about the soft skin of softshell turtles? Well, the leathery skin of softshells allow them to be lighter and much more agile. These turtles are capable of running at high speeds. In water, they can also swim very quickly.

While the lack of a hard shell makes them more vulnerable to physical injuries, this lack of a hard shell also improves maneuverability.

The shell also has nerve endings. This allows the shell to feel.

The shell absorbs heat

There is a reason why turtles have dark carapaces. The plastrons may be of light color but the carapaces are always darker in color. This is to help the turtle absorb heat.

As you may know, turtles are cold-blooded animals. This means that their bodies cannot regulate their core temperature. The dark carapace of a turtle allows it to absorb heat. This is essential if they wish to live.

Not only does the shell absorb heat, but it also helps to prevent overheating within the turtle’s body. The shell also protects the turtle from dehydrating.

Even freshwater turtles need to bask. The shell protects the turtle from dehydration while basking.

The shell absorbs UVB

UV Lighting
UV Lighting

Chelonians like many other reptiles need UVB & UVA light to be healthy and grow as they should. UV light allows them to synthesize vitamin D which is needed for healthy bone and shell growth.

Without vitamin D, the turtle can suffer from a wide variety of health issues such as metabolic bone disease.  This can lead to a deformed shell and deformed limbs.

When left untreated, the disease can cause permanent deformity. This can even lead to death.

Since the shell has a large surface, it is very important in absorbing UV light (both UVB & UVA). As mentioned earlier, the shell is partially made up of skin.

This skin plays an important role in the absorption of sunlight.

See our UVB guide for more about why they are needed and what are the best options if you have a pet turtle.

Ensuring your turtle’s shell is healthy

As already mentioned, the turtle’s shell is important. A chelonian with an unhealthy shell is an unhealthy turtle. Several conditions can impact the well-being of your turtle’s shell.

We will look at the most common and significant health issues that can affect your turtle’s shell.

Injuries

It is not uncommon for the turtle to injure its shell. Injuries can range from superficial to serious. Superficial injuries include surface lacerations and bruises. These are usually caused by sharp objects and edges within the enclosure. 

Ensure that all surfaces within the enclosure are smooth. Substrates, toys, and other objects within the enclosure shouldn’t be able to cut or bruise the turtle.

Particular attention should be given to softshell turtles. Since they have leathery shells that are more prone to injuries.

Serious injuries include deep lacerations and cracked shells. Housepets such as dogs are usually culprits in such serious injuries. It is essential to keep your pet chelonian well-protected from other household pets as well as pests such as raccoons.

Treat superficial injuries with a topical solution such as betadine solution (1 part betadine & 10 parts water).

For serious injuries such as a cracked shell, you need to see a herp vet.

Metabolic bone disease (MBD)

Metabolic bone disease in turtles
Yellow bellied slider with MBD

This is a disease that affects the development of the shell and bones of the turtle. It leads to malformation of both the skeletal structure of the turtle. 

Metabolic bone disease is caused by vitamin D and/or calcium deficiencies. This is usually down to improper diet and lack of exposure to adequate levels of UV light.

Other causes include disease to the parathyroid glands, kidneys, and liver.

Metabolic bone disease can be prevented through good husbandry. However, if you notice signs of shell and bone malformation, contact your vet.

When caught early, the malformation can be corrected.

Pyramiding

Marginated tortoise with pyramiding
Marginated tortoise with pyramiding

Pyramiding is where the scutes grow in a pyramid shape. This is caused by dietary deficiency such as calcium deficiency or lack of fiber in the chelonian’s diet.

Other causes include excessive protein content in diet and overfeeding (check the links for more about overweight turtles and overweight tortoises).

You can prevent pyramiding by feeding your turtle a balanced diet (balanced for a turtle) at scheduled intervals. Don’t overfeed your turtle.

Retained scutes

This happens with turtles that shed their scutes. Sometimes old scutes are not properly shed while new ones grow underneath.

This happens when the turtle doesn’t bask enough. Why are retained scutes bad? Well retained scutes can easily get infected.

Have a veterinarian treat retained scutes.

Ulcerative Shell Disease

This can be prevented through good husbandry. YOU need to maintain a clean enclosure. Clean the turtle’s tank regularly. Shell rots or ulcers occur when cuts and lacerations become infected.

They can also be caused by fungal infections.

Shell rot is best diagnosed and treated by a veterinarian. Treatments include antifungal medication (if the ulcer is caused by fungal infection), or topical or injectable antibiotics if it is caused by a bacterial infection.

Conclusion

The turtle’s shell is an integral part of the turtle’s body and is probably the most identifiable characteristic of a turtle. Most chelonians can tuck their limbs, head, and tail into their shell.

Some such as box turtles can even close up their shell. The shell offers protection against predators, diseases, and even trauma.

But can a turtle live without a shell? Well, they cannot. The shell is a part of their body. The ribs and spine are fused to the shell. Unlike popular cartoon turtles (such as Cecil Turtle who can walk around with a shell), real turtles cannot live with a shell.

If you have any questions or suggestions, kindly leave a comment. Thanks.

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