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The Ultimate Guide To The Tortoise Anatomy

By Kerry
Updated on

Tortoises are fascinating creatures. Many people own them as pets.

They have a very interesting anatomy to help them adapt to their environment. This article will talk about the anatomy of a tortoise, from what its shell is made out of to how it senses things.

Tortoise on green grass

The Shell Of A Tortoise

Tortoises are reptiles that have shells. Their shells protect them from predators. and are made up of calcium carbonate, making them very hard and durable. 

Their shells are made up of two halves. Their ribs are located on the outside of the body. Their shells are also usually brown or black. 

A tortoise’s shell is formed by adding new layers of keratin on top of the previous ones. This process causes growth rings, which are visible when you cut into the shell. These rings help scientists determine how long ago the tortoise was born.

Tortoises grow slower in colder climates than in warmer climates because there isn’t much vegetation. So less food equals less growth and, therefore, fewer growth rings.

Tortoises have very hard shells. Their shells are made up of 5 parts called Scutes. These scutes are divided into 3 groups: Head Scutes, Tail Scutes, and Marginal Scutes.

The head scutes are directly over the head, the tail scutes are directly over the tail, and the marginal scutes are attached to the bridge (the part of the shell that connects the head and the tail).

The Marginal scutes are also known as flaring scutes because they flare outwards. This gives them more surface area than other types of scutes.

Tortoises have a rigid shell made of calcium carbonate. Tortoises lay eggs inside their shells. Their shells protect them from predators. Female tortoises have a hinge on their plastron that allows them to open up their shells to make room for their eggs. 

Tortoise carapaces are the hard outer shells of tortoises. They are used to protect the tortoises from predators.

The plastron is the softer side of the shell. It protects the internal organs from injury. The plastron has no bones, so it can move freely.

Tortoise shells are generally not used to identify species. However, some species’ shells are distinctive enough to distinguish between them. For example, Aldabra giant tortoises have a unique shell shape.

The Respiratory System Of A Tortoise

When a tortoise breathes, air enters through its nostrils and travels down its throat. Then, it goes into its lungs, where oxygen gets absorbed into the blood. 

After this, the blood passes through the heart and then back into the circulatory system. Tortoises breathe slowly because they need to hold their breath for long periods of time. 

They are much more tolerant of holding their breath than other animals. To get out of a scary situation, they retreat into their shells and stay there until they’re ready to come out.

The lungs of a tortoise are located in the top area of the shell. Their lungs are referred to as chelonian lungs, which function similarly to sponges. 

Tortoises breathe by forcing air through their nostrils, or nares, and down into their lungs with a specific motion.

 It kind of looks as though they’re shrugging, but they are actually working their limbs to help them breathe. 

Tortoises have extremely unique lungs. They are adapted in case a tortoise becomes submerged so that it can hold its breath for a long time. 

Turtles and tortoises are very different, however, and the majority of tortoises don’t really like being in the water, especially if they can’t swim!

The Digestive System Of A Tortoise

Tortoises eat plants and insects. When they eat, they chew their food with their teeth. They swallow their food whole. There are 2 main types of digestive systems: Cecum and Stomach.

Cecum – The cecum is the first section of the intestine. It starts at the bottom of the stomach and ends at the beginning of the large intestine. The cecum is where most of the digestion takes place.

The cecum absorbs nutrients from the food and breaks it down. Then, bacteria in the cecum break down the remaining waste products.

Stomach – The stomach is the second part of the digestive tract. It digests food by mixing it with acid and enzymes. The stomach also stores food for later use.

The Circulatory System Of A Tortoise

Like our own, a tortoise’s circulatory system sends blood to all of its vital organs and muscles, but a large amount is also sent under the shell to warm up before continuing to circulate around its body.

Tortoise Thermoregulation

Tortoises are reptiles that use the sun as an external heat source. Their shells reflect the sun’s rays, keeping their bodies warm. In hotter countries, they’re often light-colored.

A tortoise’s carapaces incorporate tiny pores, which help them to trap in the radiant warmth. Their shells are made of hard material that doesn’t get damaged easily. They need to be kept in a warm place. 

The Reproductive Organs Of A Tortoise

Female tortoises have ovaries that produce eggs. Eggs are laid in nests. Nests are usually found near water or vegetation. Some female tortoises carry their eggs around in their mouths, while others bury theirs.

Male tortoises have testes that produce sperm. Sperm is stored inside the male tortoise’s cloaca (a special opening) and ejaculates during mating.

The Senses Of A Tortoise

Tortoises are very sensitive creatures. They can feel the slightest touch on their shell and skin. They can sense movement in the dark. They can hear sounds from far away.


There hasn’t been much research into the effectiveness of a tortoise’s eyesight. 

We know that tortoise eyesight is decent enough because they have their eyes at the sides of their heads instead of looking straight ahead. 

However, we don’t know how sensitive or acute tortoise eyesight is.

It is thought that turtles definitely use their eyes to see movement but perhaps have trouble seeing details. 

Some tortoises are fond of certain colors, usually red. Whether it is, a real color preference or whether the animal associates it with a favorite food item is open to question.

Tortoises’ eyes are relatively narrow-looking compared to other animals. They look like they’re squinting, but their eyes are actually quite large. 

Tortoises have eyes placed more forward than they do on the sides of their heads because tortoises don’t have that big of a head in comparison with their bodies. 

They also have eyes that are located on the sides of their heads, unlike human beings.

To protect their eyes from sand while burrowing, tortoises possess a third eyelid to keep sand out of their eyes. You can often barely see this eyelid. So don’t worry if you can’t see any sign of your pet tortoise’s third eyelid.

There aren’t a whole lot of studies done about exactly what a tortoise can see. They appear to have fairly good eyesight. 

A tortoise can only see in a narrow range of colors, which helps them find brightly colored fruits and flowers when they’re out in the wild. 

To test this, simply hide a strawberry in their enclosures to see how long it will take them to notice it.


Many publications have tried to give the impression that tortoises cannot hear anything at all, although it is fair enough to say that their hearing differs from ours and may be less sensitive to high frequencies, but they are not deaf.

The ears themselves have nothing external to them and can be best described by saying they are simply flaps or scales that are located behind the tortoises’ eyes towards the back of their heads.

Many people believe that tortoises don’t actually have ears. This is just not true. Their ears aren’t exactly like humans or other animals, which has led to some controversy.

Tortoise ears are hidden underneath a scale beneath the eyes, just above the jaw. They are located close to the rear of the tortoise’s head. The flaps or scales cover the inner ear that travels straight to the tortoise’s eardrum. 

There isn’t a consensus among scientists about what a tortoise hears, never mind whether they can actually make sense of what they hear. 

The argument goes that because tortoises, as we know, don’t communicate like dogs or birds, why do they even have ears in the first place?


A tortoise uses its primary sense (smell) to navigate and detect danger. It has a far more acute sense of smell than most owners realize. 

A tortoise relies on its sense of smell for most of its daily activities, including finding food, finding mates, finding suitable nesting areas, and smelling for predators. A tortoise uses its sense of smell for everything it does, including finding food.


Despite their odd appearance and clumsy-looking manner of walking, tortoises are actually very agile. They are incredible diggers and climbers, partly due to their excellent sense of balancing.

As the tortoise matures, its sense of balance becomes even more refined. Hatchlings observed in captivity always tend to end up on their back, while adults tend to be more stable on their feet. However, this varies from one individual to another

The Head Of A Tortoise

Their eyes are set closely together, and they use a small hole in each nostril to breathe through.

They use their nostrils to inhale and exhale air. Tortoises have long, wrinkly necks together along with five vertebrae, just like many lizards. 

Unlike all creatures, though, tortoises can move their heads directly back into their shells.

The tortoise’s head is made up of the brain, which controls the tortoise’s movements, and a jaw that opens and closes the tortoise’s mouth (the beak). The tip of the tortoise’s head is where its beak is located.

The eyes of the turtle look rather narrow. However, they possess quite large-sized eyes. 

Tortoises’ eyes have been positioned more towards their noses because they don’t possess that high of a head compared to their body.

Their eyes have also been positioned at the side of their heads instead of people’s front-facing eyes. To protect their eyes from predators, tortoises have an extra layer of protection.

The Claws Of A Tortoise

Tortoises have sharp claws. A tortoise walks a little like an elephant on its toes. It’s called “digitigrade”. Some tortoises have large claws, making them excellent diggers. They can even dig around 10 feet down!

They have heavy armor with thick scales on their front legs. The scales can look sort of like spurs or spiny structures which deter predators.

The Feet Of A Tortoise

Tortoises do not possess flippers or webbed feet (turtles do, though!). Webbed feet help them move through water, and tortoises don’t swim well. Tortoises are land creatures, so they’ve got feet and claws.

The Tail Of A Tortoise

Tortoises do have tails. For more mature tortoises, the length of their tail can be used to determine if they’re male or female. Males usually have a longer tail.

At the bottom of the tail, there’s a cloaca, which is also known as a vent. Both male and female tortoises will eliminate waste products from their cloacas.

It is basically a multipurpose hole used by tortoises for pooping, peeing, and reproducing.

The Tortoise Backbone

A Lot of people incorrectly think that tortoiseshells can be slid off and don’t understand how they keep them from sliding. 

A tortoise’s shell is fused with its bone structure, mainly the ribs and the backbones. The shell is so tightly attached to the bones that it can be difficult for them to breathe if they become overweight.

Tortoise Scales

Adult tortoise

Tortoises’ skins are typically quite wrinkly and rough-feeling. It can be hard to tell whether a tortoise is dehydrating. On the rough areas of skin, there are sections of hardened, slightly bumpy scales.

Most tortoises come in shades of gray or brown. However, these colors can vary by breed in captivity. 

Tortoises have limited color variations known as morphs. Tortoises come in different colors depending on their species and where they’re naturally found in the wilderness.

The Lifespan Of A Tortoise

Tortoises are among the oldest creatures on earth. Some species can even live up to 255 years. 

These slow-moving reptiles can survive harsh conditions, but they also need a lot of sleep. They are very sensitive to temperature changes, and they must eat every day.

A tortoise’s diet consists mainly of insects, worms, snails, fruit, vegetables, and grasses. If they do not get enough food, a tortoise may become sick. Tortoises live about 100 years on average. 

Tortoises live longer than turtles. Slow-metabolism tortoises live longer than fast-metabolism tortoises. Their shells are hard enough to protect them from predators but also make them difficult to move around.

Some tortoises come from warmer climates, while others come from colder ones. Different types of tortoises are based on their size, shape, and color. 

In the wild, they’re more likely to die due to predators, and they also live in harsher environments.

In captivity, they’re safer from predators, but they’re still exposed to other dangers. Some people aren’t careful enough when caring for them. Poorly set up conditions can lead to illness, eventually leading to death.

Tortoises are very slow-moving, but they do move. They also need a lot of space to walk around. They can be very sensitive to being too close or far away from each other. Bacteria can build up in them if they aren’t given enough space.

Tortoises need a suitable amount of proteins, which change based on their type. In the wild, environmental factors may prevent them from getting the type of nutrients they need. 

Captive tortoises that aren’t fed the diet they need get ill simply because of ignorance on the owners’ part.

Tortoise eggs hatch into baby tortoises. They grow up as juveniles and then become adults. Tortoises lay eggs about every two years. Each clutch contains anywhere from 2 to 20 eggs. These eggs take around 100-160 days to hatch.

The eggs are covered in dirt and organic material. Once hatched, the babies must crawl out of the shell before they can move.

Tortoises become adults at different ages, depending on the species. Most turtles reach sexual maturity around age 10-20. Once mature, the tortoise will reproduce. The number of rings on their shell tells us how long they’ve been alive. 

Frequently Asked Questions

What Are The Parts Of A Skeleton Of A Tortoise?

A tortoise’s skeleton comprises two parts: an exoskeleton made from a carapace and plastron, which is split into the appendicular and axial skeleton, and an endoskeleton made from internal bones. 

What Do Tortoises Eat?

The majority of tortoises need a diet that is high in fiber and low in protein. You should provide a leafy green diet and use Calcium D3 Vitamin powder twice a week to keep your tortoise healthy. 

Can Tortoises Swim?

Tortoises are land creatures and are not known to be strong swimmers. As such, you should keep your pet tortoise away from sources of water, such as garden ponds, to prevent the risk of drowning. 

Final Thoughts

Tortoises have incredible anatomical features which help them to survive in different conditions, such as a robust shell and an excellent sense of balance. 

They have an incredibly long lifespan, and when they are raised in captivity properly, they can be kept safe from predators. 

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About the author


Kerry White is an avid dog lover and writer, knowing all there is to know about our furry friends. Kerry has been writing for PetDT for three years now, wanting to use her knowledge for good and share everything she can with new dog owners.Kerry has two dogs herself - a German shepherd called Banjo and a chocolate labrador called Buttons. Kerry knows more than anyone how adjusting to new life with a puppy can turn your life upside down, and she wants to ease some of the burdens through her articles.