Tortoise shells have evolved to be very strong over the millennia, protecting them from predators and extreme weather. The shell is resilient against fractures, weight, falls, attacks, and bites.
According to Composites, the fracture resistance of the average tortoise shell is 36.4 MPa m1/2.
A tortoise’s shell is stronger than a turtle’s shell, which can handle 200 times its weight. Even if the shell is damaged, it rarely exposes a tortoise’s internal organs.
Large shells can withstand more damage than small ones, and the shells of healthy tortoises are more resilient than those of tortoises with Metabolic Bone Disorder (MBD).
However, the shell isn’t indestructible, and tortoises can feel pain through their shells.
How Much Weight Can a Tortoise Shell Withstand?
The hardness of a tortoise’s shell depends on the following factors:
- Species
- Size
- Age
- Health
- Diet
- Environment
According to Herpetologica, the shell’s shape plays a significant role in its toughness.
When weight is placed on a tortoise’s shell, it’s strong enough to endure thousands of pounds of pressure. The shell can hold out as long as the weight isn’t in a small, fixed point rather than spread out.
A tortoise’s shell is tougher than aluminum, with a fracture toughness of just 22MPa m1/2. However, titanium has a fracture hardness of 95MPa m1/2, making it tougher than a tortoise shell.
Is A Tortoise Shell Stronger Than A Turtle’s Shell?
When a tortoise’s vs. turtle shell’s strength is compared, a tortoise’s shell is harder.
Tortoises evolved to have more resilient plating than turtles because tortoises can’t flee to the water when in danger. So, they rely exclusively on their shells for protection.
Few studies have been conducted on a tortoise shell’s strength. However, because we know they’re stronger than turtle shells, we can scale up the data found on the aquatic version of this reptile.
Turtle shells are capable of withstanding up to 200 times their weight.
As a result, 1,000 pounds of pressure may be insufficient to shatter a turtle shell. Sea turtles have weaker shells than freshwater turtles, making them more vulnerable to shark bites.
Can a Tortoise Carry Weight?
Tortoise shells are like rib cages fused to the tortoise.
The shell’s shape may distribute weight rather than cracking. However, the leg bones, joints, and muscles lack the strength to pick themselves up when weight is placed on its shell.
Tortoises have powerful, stumpy legs that carry around their heavy shells. However, they’re not designed to carry additional loads, so they can’t become pack mules.
Tortoises crawl on their toes as they walk, so their entire weight is concentrated on their feet. Day after day, they must traverse their environments while carrying that large shell.
It’s a difficult endeavor, but they succeed by taking frequent rest breaks. However, putting additional weight on their backs can be stressful, damage their legs, and cause respiratory issues.
How Strong Is a Baby Tortoise Shell?
Tortoises don’t hatch with a shell as strong and durable as they have once they reach adulthood.
All baby tortoises grow and strengthen as they age, so a tortoise will have a softer, weaker shell when it’s a hatchling. This initially fragile shell takes about 5 years to harden and become fracture-resistant.
Hatchlings are vulnerable during their early years because they can’t shelter under a tough shell, like mature adult tortoises.
To understand how fragile a baby tortoise’s shell is, know that small predators can bite or chew through it. Predatory birds can drop a baby tortoise from a height, causing the shell to break open on impact.
As the tortoise matures, its shell becomes thicker and stronger. Hence, adult tortoises can survive falls and pressure much better than baby tortoises.
Is a Tortoise’s Shell Indestructible?
A tortoise’s shell may be durable, but it can still be cracked or destroyed.
According to Gems & Gemology, a tortoise’s shell is scientifically classified as a natural polymer due to its structure. This consists of long chains of organic molecules with a high molecular weight.
So, the shell is resilient but not indestructible or bulletproof.
Scutes
The scutes are thermoplastic, so they can be heated to make them flexible and pressed into a mold.
Once cooled, they return to their hardened state. The interior structure of the scutes, which is made up of thin plates that are stacked, is altered in this way. So, a tortoise’s shell is hard, but not so hard that it’s impervious to damage.
The scutes range in thickness from ⅛ to ¼ of an inch and weigh between 5 and 25 pounds.
Bones
A tortoise has an exoskeleton (carapace and plastron) and an endoskeleton (appendicular and axial).
The carapace is the top section of the shell, while the plastron is the bottom section. Keratin plates form the plastron and carapace, giving the tortoise’s shell its toughness and resilience.
It’s resistant to weight but less resistant to focused, piercing attacks, such as those from predators’ teeth and beaks, which is why scratches are so common on tortoise shells.
Plastrons have a flat structure that shields the internal organs and protects the tortoise when turned upside down by predators. Both comprise keratin and add a hard coating to the tortoise’s shell.
Keratin supplies these tissues with a strong, fibrous framework. The microscopic structure of keratin is crucial to its resilience and flexibility, but it can still be damaged.
Are Tortoise Shells Bulletproof?
Now you know how strong a tortoise’s shell is, the thought of a bulletproof shell might have crossed your mind. However, this is just an urban myth.
Tortoises use shells to defend themselves from predators. Their thick shell is advantageous, making it difficult for predators to eat or get their teeth around them.
Although tortoise shells are durable, they’re not bulletproof. When fired, bullets move at such a high speed that they can penetrate even the toughest materials, including a tortoise’s shell.
A tortoise’s shell has many bones joined together, and the shell has nerves and vessels that circulate blood within it. Therefore, if a bullet strikes the shell, the shell will be injured, and blood will flow.
Can a Tortoise’s Shell Break?
Despite how strong it is, a tortoise’s shell can break, even from the impact of falling from a height.
In addition to accidents, health issues such as pyramiding and starvation can cause the shell to crack. Inadequate basking areas and opportunities to hydrate can compromise the shell’s health.
The uneven development of scutes in a tortoise’s shell is called pyramiding. The shell may crack, fracture, or shatter with this condition, resulting in a distorted shape.
If a tortoise doesn’t receive optimal nutrition and hospitable environmental conditions to accommodate the growth of a healthy shell, it can be more prone to fractures and deformities.
Even though a tortoise’s shell is among the most resilient defensive coverings, crocodiles, badgers, sharks, hippos, and birds can break it. So, a tortoise’s shell isn’t impenetrable.
A tortoise’s shell can heal from minor fractures but can’t repair itself when severely cracked or damaged.
