What Is Inside A Turtle Shell?

When we think about turtles, we often imagine them retreating inside their shell as if it is a safe little home for them to hide in. This is not actually the case. A turtle shell does not act like a home for the turtle, as it is actually part of the turtle’s body, made up of bones, skin and keratin.

What Is Inside A Turtle Shell?

Turtles are fascinating creatures, with unique anatomical features and characteristics. You may be a fan of turtles, but have never thought about why they look the way that they do, or why they have a shell? We are here to help you understand more about these spe-shell  animals, what their shells are, and what is inside a turtle shell.

What Is A Turtle Shell?

A turtle shell is essentially an extremely complicated shield for the turtle, protecting all of its vital organs and enclosing its body from harm. The turtle shell works as extra armour protecting the turtle inside. This is what makes the shell turtley awesome! 

The turtle shell is actually an extension of the reptile’s rib cage, acting as a bony shell that keeps the interior of the turtle safe. The turtle shell has remained relatively unchanged after years and years of evolution, and acts as the animal’s primary defense mechanism from all sorts of predators. 

A turtle’s shell is made up of many small bones, and is divided into two halves. The underneath part of the shell is known as the plastron, whereas the top part is called the carapace. The shell itself is made up of numerous little bones covered in plates of keratin called scutes.

The Anatomy of a Turtle Shell

The turtle shell works all at once as a barrier, and is part of the turtle’s skeleton. The shell acts as the rib cage, spine, vertebrae and the sternum, and is made up of various parts. 

Three Turtle Shell Parts

You may be surprised to find that a turtle shell actually has three different parts. These parts are the bridge, the carapace and the plastron.

The first part of a turtle’s shell is the upper part, which is called the carapace, whereas the lower part is called the plastron. The third section is called the bridge, and it works to connect the two separate parts together, the carapace and the plastron.  

Scutes

In addition to the three parts, there are scutes on the turtle shell. These scutes form the outermost layer of the turtle shell, made up of keratin much like human nails are. These scutes are layered, making them extremely tough, durable and flexible. 

This extra layer of scutes works to protect the bone part of the turtle shell from retaining damage. As land turtles and tortoises grow and age, the scutes grow along with it, and the turtle shell will have new rings and patterns.

On the other hand, turtles that are aquatic will actually shed their old scutes when they grow and change, making it seem as if the turtle shell is peeling. 

The Carapace

The carapace is an easy part of a turtle’s anatomy to point out. This part is the dome of the shell on the turtle’s back.

It is the convex, curved part of the shell, made up of rib bones and dermal bones. This part of the turtle shell works as both the ribs and the backbone of the shell through the process of ossification.

On top of the bones found here is the skin, which is covered in scutes made of keratin. The scutes work to protect these bones from scrapes, bruises, and any damage.

The carapace is made up of a multitude of different bony plates that form the turtle shell. These plates come together to form the skeleton outline of the carapace and topmost part of the shell. These bones are made up of a multitude of plates, including the proneural plate and neural plates. 

The proneural plate is the bone that is located at the front center part of the turtle shell which is nearest to the point where the head would be. The neural plates are found just after the proneural plate at the front part of the shell.

These plates also go down the middle part of the shell in a sort of line formation towards the tail. Some turtles will have around 8 neural plates that go down the back of the shell. 

Just at the end of the neural plates near the tail of the shell, you will find the suprapygal plates. There are typically two of these bones that sit at the tail. Next to this, there will be a pygal plate at the tail end, and every turtle will only have one!

Along the sides of the neural plates, we will also find the pleural plates. There are generally around 16 pleural plates on each turtle, and these are very long and wide plates that encompass the neural plates in the middle.

Lastly, there are peripheral plates that go along the edge, or the peripheral part of the carapace on the turtle shell. There can be up to 22 peripheral plates on some turtles, as these bones go around the entire outer part of the carapace. 

Carapace Scutes

On top of these bony plates of the shell, you will find the scutes. The majority of turtles will have around 13 main scutes and 24 smaller scutes on top of their shell. These scutes are actually visible on top of the shell and can often be used to identify turtles from one another.

The scute just behind the turtle’s head is called the nuchal scute, whereas in the center of the shell, there are central scutes. Typically, there is only one single central scute on a turtle shell. 

Nex to the central scute, you will find the precentral scutes. There are typically four of these, and will be found close to the center of the shell. Together, the central scutes along with the precentral scutes are called the vertebral.

On each side of the vertebral, you will be able to locate the lateral scutes. In addition to this, there are much smaller scutes that are found along the edge of the carapace and go all of the way around the shell. 

Both the carapace and the scutes make up the top part of the turtle shell, whereas the plastron is the underside of the shell!

The Plastron

The plastron is the part of the shell that is on the underside of the turtle. This is the flattest part of the shell, as is made up of roughly nine bones of the turtle. In addition to this, the plastron includes both the anterior and posterior of the shell as well as the bridge. 

This part of the shell encompasses the epiplastron and the entoplastron. The epiplastron is located at the front part of the plastron. Each turtle will have two epiplastra, the left and the right, and will be located likewise on each side of the turtle shell. 

The entoplastron is just below and underneath the aforementioned epiplastra. This part of the shell borders both of the epiplastra parts and the hyoplastron below it. 

The hyoplastron also has two hyoplastra too, which are located underneath the epiplastra on both sides of the turtle shell. In addition, there are another two hyoplastra underneath, meaning that there are four in total. This part makes up the majority of the middle of the turtle shell underneath.

Then, you have the xiphiplastron underneath the hyoplastra, which is located towards the back part of the shell. There are two xiphiplastrons on the shell. 

Finally, there is the bridge section that connects the underside of the shell (plastron) to the carapace. 

Plastron Scutes

Much like the topside of the turtle shell, the underneath side has scutes. However, there are not as many. Generally speaking, the plastron has 6 different types of scutes. This includes the gular scutes, which are a pair of scutes that are found just behind the turtle’s head. 

Then you have the humeral scutes just behind the gular scutes, followed by a pair of pectoral scutes. Underneath these are the abdominal scutes and then the femoral scutes. At the bottom most point, you will find the anal scutes of the turtle, which also come in a pair. 

Anatomy of A Turtle

The anatomy of a turtle is so unique, and unlike that of any other animal on earth. Only in turtles and tortoises do we see such shells that are made up of so many bones and anatomical parts.

The turtle shell is so distinctive to this type of reptile that it offers many questions concerning its build, strength and capabilities, or even the question: what is inside a turtle shell? 

What Is Inside A Turtle Shell?

The purpose of the turtle shell is to keep its internal and vital organs safe at all times. The shell acts as a barrier of protection for the turtle’s heart, lungs and reproductive organs. 

If you have ever wondered what is inside a turtle shell, then you are in luck. We have here all of the internal organs and parts of the turtle that are protected by its shell. These are:

  • The lungs- respiratory organs of the turtle
  • The esophagus- the passage from mouth to the stomach
  • The heart- the organ that pumps blood through a turtle’s body
  • The trachea- the windpipe of a turtle or tortoise
  • The stomach- the part of the digestive system that is found between the esophagus and intestines
  • The bladder- where urine is stored
  • The liver- where bile is produced
  • The pancreas- where digestive enzymes are produced
  • The rectum- the end of the digestive tract/system
  • The anus- this part acts as the outlet for the digestive tract

Can a turtle live without its shell?

As the turtle shell is part of its body, and actually houses the reptile’s backbone, it is impossible for a turtle to live without its shell. The turtle shell is actually one of the most vital parts of the animal’s anatomy, and living without it would be inconceivable.

However, a turtle can survive with a heavily damaged shell, as the shell is a very powerful part of its body. The turtle shell can sustain a lot of damage, cracks and shatters without impacting the turtle itself too much.

That being said, if you find a turtle or your own turtle has a heavily damaged shell, you should seek medical or professional attention for the turtle. 

How hard is a turtle shell?

Because a turtle shell is made out of bones, it is actually very strong, hard and durable. However, some turtle shells can feel quite soft to the touch, and these types of turtles are actually called softshell turtles.

Most turtles will have soft feeling shells, but the shell itself remains very strong and powerful, capable of protecting the reptile completely. 

The turtle shell will in effect act as a shock absorber for the body underneath, working as a layer or barrier from harm. That being said, it is not impossible for the turtle shell to become damaged, and predators can attack the shell, harming or even killing the turtle inside. 

What does a turtle look like without its shell?

As turtles cannot live without their shells, a turtle without a shell would be a dead turtle.

In addition, there are no turtles that exist without a shell, and so we may never know what a turtle would look like without a shell. 

What is a turtle shell called?

There is no specific or proper term for a turtle shell other than the turtle shell.

The only professional way it is referred to is by its separate parts; the carapace, plastron and bridge. Other than that, it is always called the turtle shell. 

What colors are turtle shells?

Turtle shells can come in a variety of different shapes and colors, and the answer depends on the type of turtle. The most common colors of turtle shells are tan, brown, black, and green. 

However, this will depend on the specific species of turtle as yellow-bellied sliders will have yellow colored plastrons, whereas common turtles will have olive-green and brown turtle shells. 

In addition, the red-bellied cooter has a more red colored plastron, whereas map turtles have a more green tone to their shells with various markings. 

Conclusion

All species of turtles and tortoises will have various different shells of varying shape, size, colors and softness. However, all shells are there to protect the internal organs of the turtle and work as a protective barrier for the turtle, warding off predators that would harm or kill the turtle.

Not only this, turtle shells also work to protect the reptile from the elements and extreme weather conditions. 

The turtle shell does not house the turtle, but is actually made of the turtle, composed of bones, skin and keratin that keeps the turtle safe. The shell is therefore a part of the turtle’s body and anatomy, capable of bleeding or retaining damage just as an animal’s limbs or bones would be. 

Dorothy Razo
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