How Hard Is A Turtle Shell? [More Than You Thought!]

The information is current and up-to-date in accordance with the latest veterinarian research.

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The first thing that makes turtles unique is their unique shell. According to a report, the last 210 years of evolution have brought about bewildering changes in the turtle’s physical features. It also includes shell varieties. Have you ever looked at the turtle shell and thought, “Why do turtles have shells?” or “How hard is a turtle shell?”

Sources claim that turtle shells can withstand forces 200 times their own weight, which can be thousand pounds of pressure. According to the studies, a turtle endures a fracture toughness of 36.4 MPa m^0.5 and maximum flexural strength of 165.1 MPa.

How does a turtle shell withstand this much pressure? Is the shield bullet-proof or unbreakable? The following article includes all the answers to the hardness and toughness of a turtle shell.

How Hard Is A Turtle Shell?

Well, you can not assume the exact hardness of a turtle shell. It is because different parts of the carapace can endure different strengths. Also, the withstand pressure varies from species to species as the physique of the turtle changes.

But yes. You can definitely have an approximate answer. Different groups of scientists have already researched the hardness and toughness of a turtle shell. In this section, I am simplifying the data for you.

Researchers have conducted all types of hardness experiments on a turtle shell. Not all of the data is necessary right now.

First, let’s talk about the tensile strength of a turtle shell. For those who do not know, tensile strength refers to the maximum load any material can withstand without fracturing while being stretched.

You know, the turtle shell is curvy. So, the scientists have divided the carapace into 3 layers to determine the approximate strength. Here is achieved data,

Interior Layer Middle Layer Exterior Layer
40 MPa19 MPa28 MPa

For many species, this tensile strength ranges between 19 MPa to 52 MPa. Compared to the tensile strength of glass and wood, respectively 52 MPa and 40 MPa, the chart numbers are impressive.

On the contrary, compressive strength indicates the maximum load any substance withstands. For turtles, the approximate compressive strength is about 100 MPa.

Remember, turtle shells are hard and brittle. Hence, the elongation or size reduction is not more than a few microns.

If you apply a bending force on a turtle shell, the strength increases to 165.1 MPa. It is known as maximum flexural strength.

What if your turtle’s shell already contains a scratch? The studies support that a turtle shell has an average fracture toughness of 36.4 MPa m^0.5. Fracture toughness is the force essential to scratch the turtle scute surface.

Do you think fracture toughness of 36.4 MPa m^0.5 is not enough? Well, you are absolutely wrong.

If you look at the metal fracture toughness, the aluminum has a rating of 22 MPa m^0.5. So, yes, turtle shells are stronger than aluminum and many more metals.

In short, turtle shells are harder and can endure more pressure than many other naturally occurring materials.

How Much Force Does It Take To Break A Turtle Shell?

The sources claim that empty box turtle shells resist forcing up to 200 times their weight. It is about 1000 pounds of pressure. So, you have to overcome this pressure to break a turtle’s shell.

According to a study, a minimum of 36.4 MPa m^0.5 fracture toughness is required to cut through the turtle scute surface.

However, it is not easy to break a turtle’s shell. The simple ramming or a thud will not damage the scutes and might scratch the surface at best.

A turtle gets its shell damaged when it faces an accident or falls from a height. In the wild, crocodiles or alligator bites have the force to break a turtle’s carapace.

The biting force of an alligator and crocodile is respectively 2125 to 2980 pounds and 3700 pounds. It is, of course, powerful and far more than what a turtle shell withstands.

Hence, we can conclude that breaking a turtle’s shell requires enormous pressure. Primarily, we assume that force to be around 1000 pounds.

But yes, if the shell is underdeveloped or the turtle is suffering from malnutrition, damages will be done with lesser force.

Again, the sea turtles and the softshell turtles have soft shells. So, fracturing or scratching the surface is easier on these scutes.

Which Turtle Has The Hardest Shell?

Determining the exact hardness of a turtle species is nearly impossible. Yet, the scientists and researchers have reached a conclusion depending on the observation.

It is assumed that the sea turtles have stronger shells than the aquatic or semi-aquatic ones. The sea turtles have to dive in deep water and survive the immense pressure force on the shell.

The loggerhead sea turtles own the strongest shells compared to other marine turtles.

Do you find identifying a turtle species confusing? Follow my article on how to identify turtles and be an expert.

Is A Turtle Shell Bulletproof?

Turtle shells are not indestructible and definitely not bulletproof. While a turtle shell can withstand 1000 pounds of pressure, a bullet can generate a force of roughly 16000 pounds at the muzzle.

I have already discussed the toughness of a turtle shell. These shields are hard and safeguarding, and there is no doubt about that. But they will not protect the turtles from all dangers.

Turtle shells can barely survive the powerful jaws of alligators or crocodiles. When it comes to bullets, the defense is not that strong.

Bullets travel at an extreme speed while firing. As these leads work on a small area, they generate a great deal of force at the muzzle. It is way more powerful and deadly than the predator bites.

The studies show that a bullet produces roughly 16000 pounds of force, and the turtle shell resists only 1000 pounds. So, the bullet will penetrate the carapace within seconds.

You know turtle shells are composed of bones and contain blood vessels under the tissues. If they are struck by a bullet, the scutes will get damaged, injuring the turtle severely. In worst cases, the turtles will have broken ribs and wounded limbs.

However, turtles taking a bullet is the rarest event by far. But if these creatures ever meet the lead, they will have injuries beyond repair.

Can A Car Crush A Turtle Shell?

A car coming at a turtle at full speed will smash its shell. Even a small hit by a car can damage the turtle shell.

Turtle shell injury due to a road accident is more common than you think. The gravid turtles often migrate to new places during the nesting season. They have to walk miles in search of a suitable egg chamber.

The female turtles cross all the boundaries and obstacles between them and the nesting places. When the mother turtles are done laying eggs, they will return home. Surprisingly, the turtles own a strong sense of direction. While crossing the road, these turtles often fall victim to deadly accidents.

A turtle, of course, can not run or speed up its movement while crossing the road. The average running rate of a turtle is 3 to 4 miles per hour, and running is not easy for these reptiles. Check this article to find out why a turtle can not run faster.

You know the turtle shells are made of bones and ribs and can handle the pressure of about 1000 pounds. A speedy car hits a passing turtle with more force than that. So, a damaged or cracked shell is the outcome of a car accident. In the worst scenario, the cars will smash the carapace and crack it wide open.

Surprisingly, a turtle can survive days even with an injured shell. An animal rescue center report claims that a turtle, hit by a car and left on the roadside, lived for weeks. Any help in the timeframe can heal the turtle.

If you ever see a wounded turtle on the road, be kind to it and take the animal to a vet. If the injury is severe, contact an animal shelter or ask for help. Here is a step-by-step guide on rescuing turtles.

Can We Break The Shell Of Turtle?

You can not break a turtle shell with your bare hand, no matter how hard you try. Turtle shells can withstand forces 200 times the weight, and so you would require an external source to do the cracking.

What on earth would anyone try to break a turtle shell? I know the carapaces are strong, and depending on the position, the surfaces can withstand more pressure than many metals. But it does not mean you should be careless about the turtle.

A normal thud or even an average hit will not do any harm to the turtle’s carapace. Yet, you have to be gentle while handling or carrying these creatures. An innocent-looking crack on the scutes might get severe if infected by bacteria or fungus. Again, falling from a height or running over by cars can damage the shell.

What Can Break A Turtle Shell?

Anything that can generate force over 1000 pounds might damage the turtle shells. Generally, predators with powerful jaws, like whales, sharks, crocodiles, alligators, etc., are able to break the turtle shell with their bites.

Turtles use their shells for protection against deadly animals and to hide. Sometimes these creatures can not beat the predators due to the lack of speed and become victims of their bites.

So, which animals can break a turtle shell? Here is a list,

Crocodile and Alligator

I have already mentioned the powerful bites of crocodiles and alligators. While an alligator can generate 2980 psi force with its sharp jaws, a crocodile has the ability to apply 5000 psi. These pressures are way more than a turtle shell can resist.

Hence, crocodiles and alligators can smash the turtle shells. In fact, these two predators are the main enemies of the wild turtles.

But yes, I have seen videos of turtles and alligators swimming together. So, it is not always necessary that the crocodiles or alligators attack the sweet, innocent turtles.

Whale and Shark

The sea turtles have flexible and softer shells. They fear whales and sharks, especially tiger sharks.

Tiger sharks love feasting on the leatherback sea turtles. The sharks and whales have strong bites. However, cracking sea turtle shells does not require much force.

Honey Badger

Different studies suggest that a honey badger has an average biting force of 1100 pounds. It is enough to smash the turtle carapace. The turtles fear the honey badgers as these creatures love the bony taste of the shells.


I admit, birds do not have the strength to crack a turtle shell. But they have the intelligence. A viral video shows a seagull carrying a stone-like thing at a high altitude while flying and dropping it on the ground from the height. It simply cracks and opens the rocky shell.

Can Turtles Shell Break?

Turtle shells are not easy to crack. However, a few physical conditions can weaken and deform this shield. As a result, it takes much less force to break the shell.

So, what conditions am I indicating?

One of the common reasons that weaken the turtle shells is pyramiding. It refers to the deformed and uneven growth of the scutes. The turtle shell might get split, cracked, or broken due to this disease.

What causes pyramiding? Overfeeding of protein is mainly responsible for this condition. Other reasons are,

  • Lack of vitamin D3 and calcium in the diet
  • Inadequate UV rays
  • Improper environment, etc.

What Is A Turtle Shell Made Of?

Turtle shells are made of bones that fuse the turtle’s rib cage and spine. The exposed bones are covered with plate-like scutes and build the carapace and plastron structure. Each turtle shell consists of 13 small scutes on the top.

You have already witnessed the strength a turtle shell possesses. But what is the secret behind that?

Of course, the materials of the shells make all the differences. But you can not ignore the engineering of both the carapace and plastron.

Allow me to break down the structure of a turtle shell.

If you remove the carapace and plastron from the turtle body, it is nothing but a web of bones interconnected to each other. The rib cage and the turtle spine get connected to the main structure via the bones.

Scutes are the plate-like pieces that get together and shape the carapace and plastron. These upper and bottom parts of the shells are fused at the edge. It is called a bridge.

The scutes build the main structure of the turtle shell. Scoots, a layer of keratin, covers the scutes. It is the same thing that can be found on human nails and hair.

Can A Turtle Survive Without Its Shell?

A turtle can not live without its shell. If you look at the physique of a turtle, you will notice that the plastron and carapace are fused with the spine and rib cage. So, yes, this part of the turtle is inseparable.

Why do you think turtles own a shell? The most common answer is for security purposes.

Turtles use the shells as their hiding spot from the predators and the rest of the world. I have to admit that the shells are great shields against any danger in the wild.

However, safeguarding life is not the only purpose of the turtle shell. While swimming in the water, the engineering of the shell comes in handy.

The streamlined and smooth shells help the aquatic and semi-aquatic turtles glide through the water. This article on the swimming mechanism of sea turtles will help you understand this purpose clearly.

Again, shells are essential for the healthy growth of turtles. You know turtles bask in the sun to get vitamin D3, which helps them absorb calcium later. As a result, the turtles will have a solid body structure.

If someone paints the turtle shell, it hampers the UV absorption. So, the turtle will end up having a bumpy and underdeveloped shell.

In short, turtles can not live without shells, and yes, these are inseparable.

Can Turtles Survive With A Broken Shell?

Turtle shells are not indestructible, and any severe accident can damage this shield. But thankfully, a broken shell is not the death of the turtles. The injured turtle survives a few weeks even if it does not receive any treatment.

Cracked shells always make the turtles vulnerable. Untreated wounds increase the risk of fungal or bacterial attack, and eventually, the turtles fall victim to shell diseases.

Mark my words. Shell rots can be worse in turtles.

Again, accidents are not always responsible for the cracked shell of a turtle. Pyramiding, hitting on an edgy surface, poor diet, unhealthy habitat, etc., often lead to shell diseases.

As a responsible owner, you should take good care of the turtle shell. It includes a proper habitat and a healthy diet.

Also, if you notice a scratch or crack on the shell, consult an expert immediately before the situation gets worse.

Can Turtle Shell Grow Back?

I know it sounds unbelievable, but turtle shells grow back all by themselves. Yes, you have heard it right. The shells have similarities with human fingernails, and if your nails can grow back, so do the damaged scutes.

But there are some facts you must know.

The shell growth rate is much slower than you can imagine. It might take up to 30 months to heal a broken shell naturally. And yes, the new shell structure will never match the original one.

What will you do if your turtle breaks its shell in an accident? Will you wait for 30 months?

Of course not. The exposed area leads to vulnerability, and soon the turtle will suffer from shell diseases and other physical conditions. Hence, take the pet to a vet and repair the shell with artificial bonding materials. It is a better decision for the turtle.

How To Fix Cracked Turtle Shell?

Turtles fracturing their shells in an accident is nothing uncommon. But thankfully, you can offer them the primary treatment at home for minor damage.

Here are the steps you have to follow to fix a crack turtle shell,

  • Clean any dirt or blood from the wound using diluted iodine or chlorhexidine solution. Continue the cleaning session for 1 week.
  • Keep the turtles dry and let them bask for more hours. Swimming for hours will cause more damage to the wound. Instead, soak the shell with a damp towel every day.
  • Apply antibiotics and disinfectant on the wounds every day.
  • Now, owners often use fiberglass patches and glue to fix the crack. Remember, only experienced keepers should try this at home. If you are new to this, do not experiment with your turtle.
  • Only a fiberglass patch is not applicable for the water turtles as the glue comes off. A resin coating is necessary to seal the patch. Vets often use dental composite to fix the cracks.

If the crack is severe and you feel nervous dealing with the injured turtle, take it to an exotic vet.

Do Turtle Shells Feel Pain?

Turtles can feel their shell and any pain or injury on it. The turtle shell is permanently connected to the spine. So, the spinal cord nerve endings running through the scute surfaces allow these creatures to feel the touch or pain on the shell.

In the previous section, I have discussed the formation of a turtle shell. So, you already know that the scutes are connected to the bones, spines, and rib cages of the turtles.

The spinal cord nerves run all over the shell surfaces. Hence, turtles feel any touch or pain associated with the shell.

However, the scute plates on the shell are layered up with keratin. The human hair, nails, and animal horns contain the same keratin element. Scientists believe the turtle shell acts like human nails because of the scoot or keratin layer.

It means the sensitivity in this area is not as strong as the other body parts. Turtles can only feel a vibration when someone touches the shell.

But wait. Do not think the turtle can not feel any pain on the shell when it gets hurt. The outer layer of the shell transmits the vibration to the inside nerves. As a result, the pain grows, and the turtle goes through much suffering.

If a turtle shell gets cracked, the animal feels extreme pain and many experts compare it to the arm-breaking aching of humans.

Many people ask whether a turtle feels through the shell or not. The answer is yes.

Turtles can feel through the shell, and the intensity depends on the turtle species.

Generally, the turtles with soft shells are more sensitive about touch than the land turtles. However, the sea turtles, especially the leatherback sea turtle, have much stronger shells than the rest species. They dive into the deep ocean and handle the water pressure like a cup of tea.


Turtle shells are hard, and it is not possible to break without applying force over 1000 pounds. Wild predators fall from height, and accidents might damage a turtle shell. If you ever spot a turtle with a broken carapace or plastron, take it to a vet for treatment.

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About Author

Muntaseer Rahman started keeping pet turtles back in 2013. He also owns the largest Turtle & Tortoise Facebook community in Bangladesh. These days he is mostly active on Facebook.


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