Turtles Shell (All Questions Answered)

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The turtle shell is primarily made of two things, keratin and bone. Keratin is the same material that makes up our nails. The shell has two types of bones – the skeletal and dermal bones. Meanwhile, the belly or underside part of the shell is what’s referred to as plastron. The carapace is the top or backside of the turtle’s shell. The part where the carapace and plastron join is the bridge; this has posterior and anterior struts that bind the two halves together.

The carapace comprises 16 different sections dubbed as plural and divided into two halves with eight plurals each. The plurals in the carapace are made of dermal bone and ribs. Just like most vertebrates, the ribs are fused to the spine and bonded to the dermal plates just beneath the turtle skin. While the likes of armadillos have their outer shells not fused directly to the rib cage (and therefore can move their ribs freely inside the shell), turtles have the ribs bonded with the vertebrae.

The shell is further strengthened by a hard outer layer of plates known as scutes to protect the shell from the rigors of life, including standard hits from predators, thorns and minor knocks. Not all turtles have scutes though, some aquatic turtles such as leatherback sea turtles and softshell lack them.

A turtle’s plastron consists of 9 different bones that are located in the anterior divides. The bones are considered homologous to the abdominal ribs. It’s believed that the plastron evolved from the sternum that was found in the ancestors of turtles. Embryological studies have also confirmed that mutations in rib development can result in the malformation of the plastron. Besides, fossils of turtles display intermediate plastron made up of paired gastralia and dermal bones located in the ventral surface of certain reptiles.

Many amniotes accomplish respiration by contracting and expanding the muscles that are bonded to the internal rib cage. On the other hand, chelonians have their ribs bonded to the carapace. Since the carapace does not expand, turtles have evolved a variety of respiration methods. For one, turtles have a muscle sling that’s fused to the shell and can contract and relax to ventilate the lungs. Precisely, the lungs neither expand nor relax and have to rely on the power of this muscle for ventilation.

The outer side of the shell is also part of the turtle’s skin, and one may conclude that turtles molt like snakes. Well, while turtles do molt, most snakes shed all at once. Turtles molt over a long time, sloughing off tiny pieces at a time. As a result, the dead skin will pile in turtles to create thick plates for extra protection.

It’s believed that ancestors of turtles lacked hard shells. A 220-million-year-old fossil of a stem turtle was discovered in China. The fossil possessed a partially formed carapace meaning the shell must have begun long before this. Another discovered 260-million-year-old stem reptile discovered in S. Africa seems to confirm this because it has the early framework of a carapace. Their early turtle ancestors had much broader ribs than most creatures at that time. A turtle’s shell is dark green, brown and may have black coloration to it. There are exceptions, though, because some turtles have brighter shells with red, yellow or orange shells. Tortoises, on the other hand, have heavier shells compared to terrestrial turtles. The softshell and other aquatic turtles also have lighter shells to swim more swiftly and stay buoyant.

Can Turtles Live Without Their Shell?

Ancient turtles may have survived living without shells because they had not developed them. Today, turtles have developed shells and is a part of their body. The shell consists of small bones and is fused to the spine. Without the hard outer covering, turtles would be similar to melted jello.

Besides, turtles would be left defenseless even if they managed to live without a shell. The shell acts as the primary defense against predators. If it were possible to take away the shell, the turtle would be left defenseless.

Top Reasons Why a Turtle Needs its Shell

It’s Part of Their Body

Turtle’s shells cannot be physically removed from their shells, and if you did, they would die in the process. The shells comprise skeletal and dermal bone and have evolved for thousands of years to protect the reptiles. Each portion of the turtle’s shell is known as a “scute”. The scutes interlock to cover the insides and often shed thin layers as the turtle grows. Each scute has a name to be referenced, including the vertebral scutes (along the spine) and the marginal scutes (the external most scutes). The spine fuses with the turtle’s shell, so it’s a part of them. Without the shell, there’s no turtle.

Serves as Protection

Turtles are small reptiles who happen to live in the same habitat with some of the most well-adapted super-predators on the planet, such as crocodiles and alligators. Alligators, for instance, have a mighty bite force that can crush nearly any prey. Nevertheless, the biggest challenge for the alligator is the turtle.

Giant adult turtles can resist a tremendous amount of pressure, although it’s left with marks where the alligator tried to bite them but failed. This does not mean that all predators do not succeed. Some, like raccoons, are likely to succeed in breaking it or sometimes may attack the limbs. However, the turtle has evolved and will prevent a vast majority of attempted attacks.

The actual evolution of turtles is still a mystery. Two hundred million years ago marked the discovery of the oldest turtle fossil with a hardened shell. Before that, turtles were thought to have had wide ribs, although these conclusions are still limited. The plastron came first before the carapace. Besides, the shell seems to have begun with the wider ribs to assist in burrowing.

It Aids In Agility

Turtle and tortoise shells do more than just protection – it also keeps the turtle agile. An interesting fact is different species of turtles use their shell to help them burrow underground. The Gopher tortoise, in particular, uses its shell to dig extravagant tunnels underground. The tunnels can reach great depths and will often be used by other turtles, especially during hibernation. Sulcate tortoise, which is the 3rd largest tort species in the world, can create burrows using the shell.

The shell is not just helpful to terrestrial species; aquatic turtles also benefit from the shell significantly. Still, on agility, turtles that live in water have developed smooth and streamlined shells, which help them cut through the water and move with speeds, especially when running from predators. Some aquatic turtle species have also evolved keels or protruding spikes along vertebral scutes to slice through the water and protect themselves from predators. The fly river and softshell turtles have less ossification and hardening on the shell, which leaves the skin exposed, but can move at incredible speeds. Other turtles such as the Spiny Hill Turtle have evolved spikes and spines along the perimeter of the shells to deter predators attempting to eat them.

As Camouflage

Nearly all turtles have some form of camouflage, which plays a significant role in avoiding potential predators by blending into the environment. The markings of turtles are stunning, and each turtle species has evolved to suit the environment they inhabit. Sulcata tortoises are characterized by a light brown ashy appearance that blends accurately with the sandy deserts. All box turtle species are multicolored and may seem like anything can spot it. Surprisingly, they can blend so well in the wild and particularly in the forest environment. The patterns and colors allow them to mask the image of their shell. Younger turtles and tortoises have brighter but bold colors compared to adults to better blend into the environment. It’s logical considering that the juveniles are more accessible to swallow than full-sized turtles, so they need to hide much better. Still, some turtles, especially those around islands, haven’t evolved camouflage due to the lack of predators.

Shell-less Turtles of the Past? Is it True?

Since the era of dinosaurs, turtles have looked pretty much as they do now with their shells. Even if we know turtles today have shells, it’s still not 100% clear how such an elegant body structure came to be. It’s a debate that has left too many questions about how they acquired the unique suit of armor. In fact, two theories have been put forward to show how turtles got their shells.

One theory suggests that the turtle’s carapace evolved from bony scale-like growths similar to the scutes that developed on the skin of ancient reptiles. Through the ages, they have evolved to gather even more scutes that ended up fusing with the bones underneath. This is how turtles ended up forming the shells we see today, according to the first theory.

The other theory, however, insists that the shell resulted from different transformations. The dermal ossification theory suggested that ancient turtles’ ribs broadened, straightened, and later fused together to form the shell. According to the theory, the ribs lost the barrel-like curvature. This second theory, however, does not specify the reason why it happened.

In a journal named Current Biology, researchers have added fuel to the second theory. This is after further re-examination of the fossil remains of a strange-looking 260-million-year-old reptile discovered in S. Africa. The creature had a lizard-like body with short arms and legs and had a round midsection. The fossil was an early ancestor to turtles for many years, but it lost this honor in the late 1960s.

It wasn’t until another peculiar fossil reptile was discovered in China in 2008 that scientists revisited the one in S. Africa. The 220-million-year-old creature has a rounded midsection and flat ribs. Although it lacked the top shell of a turtle, it had a bony chest plate or plastron. These features shed some light on the evolution path of ancient turtles, which authors estimated to be 210 million years ago.

The oldest fossils suggest that turtles were not aquatic. Instead, they lived on land and liked to burrow. The wide ribs offered more stability for the trunk and enhanced digging. However, wider ribs reduce mobility which makes the turtle more vulnerable to predators. There was the need for more protection, so the ribs fused together over generations forming the shell. The evolution allowed them to spend more time in water and less time digging. These are just theories, but there’s still more to be discovered, and it only gets more interesting.

Can Turtles Get Out of Their Shells? 

No, and you shouldn’t try forcing them to leave the shell. The shell is a part of the animal’s exoskeleton, so there’s no way to remove the shell. If the turtle was detached from the shell, it would cause significant pain and eventually kill the animal. While turtles cannot leave their shells, they do tuck the limbs inside. Some can even close their shells tight and deter anything from outside. Never try to break inside a turtle’s shell. The muscle holding the shell isn’t very strong.

How Do Turtles Shell Get Damaged?

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Just as other animals and pets can develop complications with their skin and fur, pet turtles can also experience problems with their shells.

Car Accidents

One of the most common causes of wild turtle shell injury is being hit by a car. Drivers may not always have time to swerve away. This explains why wild turtles are usually found on the roadside and suffer from severe carapace fractures. It is even more humiliating to realize that some drivers knowingly hit turtles as they cross the road.


Predators pose a great danger to wild turtles that get into open waters. Potential turtle predators include:

Crocodile and alligators – These reptiles have extra-powerful teeth that can crack turtles’ shells.

Sharks and whales – these are also potential predators to sea turtles. When they get a chance, sharks usually attack the sea turtles and the bite is powerful enough to break their shell. However, very few sharks are powerful enough to crush the shell of sea turtles unless it’s the soft shells. Whales in the other hand can easily crush and swallow turtles.

Hippopotamus – This may come as a surprise but hippos also prey on turtles. With more power than crocodiles, a single hippopotamus bite can break a turtle’s shell. The good news is that the hippopotamuses are vegetarians and won’t attack turtles unless agitated.

Honey Badgers – additionally, honey badgers are natural predators to turtles and tortoise. These ferocious beasts will bite the shell a few times and expose the flesh inside.

Birds – Surprisingly, the vultures and eagles can easily spot turtles and make the tastiest meal. With their sharp beaks, they can attack the turtle’s shell aggressively and gnaw meat. If they force isn’t enough, they use their high intelligence to grab the claws to high heights, and drop them to the ground, breaking the thing open.

In captivity, your dog or that of your neighborhood may at times decide it has a toy to play with and chew. Deep wounds on the turtles because of dog bites may damage your little friend’s shell. If your vet does not treat the scars on the shell especially deep wounds, this may cause the shell to rot and be damaged completely.


Box turtles are brilliant escape artists, and if your pet escapes from his habitat high above the ground, he could fall and break his shell. In addition, you could accidentally drop your pet turtle as you move him. The crack may be severe at times, depending on how hard your pet falls, causing significant damage to your companion’s shell.

Poor Water Quality

Fungal and bacterial infections can be the main reason for a damaged shell. In addition, the infection can be caused by parasites. Often the infections are secondary, and if not treated earlier, they can infiltrate into the shell’s layers, thus causing pitting. That said, turtles cannot thrive in dirty water or polluted habitat.

If your pet lives in a highly humid environment or is not correctly cleaned, microorganisms can find a way to your turtle. If not taken to a vet at earlier stages of the infection, the shell may start to rot, ultimately damaging its shell. Also, chlorinated water can weaken the turtle’s shell and is toxic to the turtle eyes.


Due to malnutrition, or metabolic bone disease, your pet turtle may experience irregular growth of the shell. It can be tough to mimic their diet in the wild. A malnourished turtle is likely to have a weaker shell and later break if the malnutrition becomes too severe.

You can always look for natural diets for your turtle and then top it up with pellets. Turtles are not choosy so you just need to feed them the right food. At the same time avoid too much protein to prevent pyramiding. Pyramiding turtle shell makes it easy to crash due to uneven shell growth, thus damaging your companion’s carapace.

Irrespective of the cause of irregular shell growth, a damaged turtle shell requires urgent vet help.

A Lack of Sunlight

Though rare, a lack of sunlight can weaken the shells and cause breaking. Turtles are cold-blooded creatures and cannot control the body temperature without another source. So, when a turtle stays for some time underwater, it needs to find a basking spot to warm up. If a turtle lacks adequate sunlight, keratin will deplete on the shell, resulting to breaking.

What Happens if a Turtle Loses Its Shell?

A turtle cannot survive without a shell because it’s a massive part of the turtle. The turtle’s skin, limbs and bones are connected to the shell, meaning they cannot exist without it. If you find a turtle with an injury on its shell, you should consult a vet or wildlife center for assistance.

What Does an Empty Turtle Shell Mean?

If you find an empty turtle shell, it means the turtle has passed away. The skin, limbs and organs will decompose as soon as it does, leaving the shell. The shell will likely last longer, followed by the scutes falling, and then the shell fully decomposes.

How Much Force is Required to Break a Turtle Shell?

A turtle’s shell can withstand extreme pressure but up to a point. Different species of turtles have varying hardness in shells. Some turtles are said to have sturdy shells enough to resist up to 200 times the weight. That said, it’s safe to say that a 1000-pound pressure is likely not to be enough to break a turtle’s shell. Still, some turtles have softer shells, such as sea turtles that lack scutes.

Are Turtles Born With a Shell?

Yes, turtles are born with a shell. Prior to emerging from its eggs, a turtle hatchling should develop a shell.

Do Turtle Shell Grow With the Turtle?

Yes, turtles are born with a shell, and the shell grows as the turtle grows. Over time, aquatic species shed their scutes, and the shells grow larger. This is different in terrestrial species, though, as the scutes just peel off and grow others depending on growth.

Can Turtles Survive a Broken Shell?

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Absolutely! A broken shell doesn’t necessarily mean the turtle is dead, but it can leave the turtle in an excruciating condition. A break means the turtle’s body is opened up, similar to the crack you get in your fingernails. If the injury is left untreated, it could lead to significant infections. Sometimes poor diet and unclean tanks can cause infections that could cause ulcers around the shell called shell rot. A lack of calcium and adequate sunlight can also cause shell abnormalities, leading to ulcers. Look for signs of liver disease, kidney damage and thyroid problems if your turtle has a developing shell rot.

Do Turtle Shell Heal?

Yes. Turtle’s shells heal minor injuries, but this takes time. If the shell is ultimately, however, the turtle might not be able to heal the shell.

Which Turtle Has The Hardest Shell?

There’s no exact unit to ascertain which turtle has the hardest shell. however, sea turtles tend to have softer shells than freshwater turtles. Red-eared sliders, for instance have denser shells compared to green sea turtles.

Is Turtle Shell Bulletproof?

Turtle shells can be hard but this does not make them bulletproof. Bullets can travel at an extreme speed and can pierce some of the hardest substances. Turtles are just a mass of keratin, bones and fresh.

Can a Turtle Outgrow its Shell?

A turtle cannot trade one shell for another if its shell doesn’t fit fine anymore. Unlike a hermit crab, its shell will never fall off and is never too large or too small because it grows with the animal. The shell is made of a cage and spine and is attached to the internal bones. Just as your vertebrae grow with you, it’s the same for a turtle’s shell.

For most turtles, the scutes on the shell peel away as newer, larger scutes grow. Shedding for them is a natural process, and the scutes will intermittently fall off during daily activities such as basking and swimming. Since turtles are cold-blooded creatures, they usually rely on the temperature of their surroundings to heat and cool themselves.

As well as raising the body temperature, basking helps them to shed scutes by drying them up, making them easier to shed. Some species of turtles in South America lend each other a hand by helping them remove the loose scutes using their jaws.

When the old scutes aren’t shed often, the turtle can easily develop disease and infection. In rare instances, if the scutes are shed too frequently, they can expose the underneath soft tissue linked to renal failure.

Wrap Up

Turtles have an unparalleled natural ability to protect themselves from predators. Besides, they can burrow to survive harsh weather and become extremely agile in the water environment. The shell also allows them to blend and camouflage in their natural environment. Another thing, turtles can’t leave their shells, or they cannot live without their shells since it’s part of their skeletal system.

 The shell isn’t unbreakable though, factors such as deficiency of nutrition, a lack of sunlight and poor water quality can break the shell gradually. Furthermore, predators like crocodiles, honey badgers, sharks, hippos and alligators can crack their shells. if you have a turtle, ensure you provide him with a proper diet, and a dedicated basking spot with a heat lamp.

If you would like to know more details about turtles Shell, check out this Post: Turtles Shell Part 2

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