How to Tell How Old a Turtle Is (Full Beginner’s Guide)

Turtles and tortoises are among the longest living animals on earth. While the average lifespan depends on the species, the turtle Conservation Society approximates that most turtles can live about 10 to 80 years. However, you’ll still find turtles that live beyond 100 years. 

As a pet owner, when you bring a pet turtle home, you want to know everything about it so that you can provide the best care possible. You can learn basic things like diet, species, and providing a better habitat for your turtle online. However, one area seems to give many pet owners a hard time; knowing how old a turtle is.  

Usually, most turtles are rescued and taken to animal shelters where individuals can adopt them.  This makes determining their exact age an uphill task.

Although knowing the date when a turtle was hatched is the only accurate and reliable way to determine its age, there are various ways that pet owners can estimate the turtle’s age. In this article, we’ll help you learn different techniques that you can use to make an informed guess about a turtle’s age.

However, before we jump straight into the methods, let’s first understand why it is essential to know your turtle’s age.

The Importance of Knowing a Turtle’s Age

While it might seem like a worthless quest, finding out how old your pet is will help you create a plan to take good care of it. If you thought that knowing your turtle’s age won’t help you in any way, here are some of the reasons it is crucial.

Determine the Diet

As we all know, different animals have unique nutritional needs at various stages of growth. Knowing the approximate age of your turtle will help you understand how much food you should give it and what to include in its diet to facilitate optimal growth. If you discover that your turtle is still in its early stages of growth and development, you can increase the protein and mineral content in its food to facilitate the growth of strong and healthy bones.

Know the Breeding Capabilities

Once you estimate the actual age of your turtle, you’ll be able to determine whether your turtle can lay eggs if it’s a female. Then, you’ll be able to make the necessary preparations. You’ll make sure that the pet gets the proper nutrients that improve fertility. You’ll also know when to prepare the nesting area so that your turtle can lay eggs safely.

Anticipate Its Size When It Matures

Inherently, turtles need plenty of room and a lot of care to grow. One of the factors that will determine the size of the pool, tank, or enclosure you’ll need for your pet is its size. As a turtle pet owner, knowing your turtle’s age helps you anticipate its size when it matures. This way, you can provide living standards tailored to your turtle’s unique needs at different stages of growth.

A turtle might have a small body only to grow beyond the living conditions and the habitat you provide. Conversely, you may think that a turtle is young due to its small body size, only to realize that it’s actually in its prime.

Plan for Its Existence Once You’re Gone

The relationship between a pet turtle and its owner is one of the longest relationships ever. While human beings have a lifespan of not more than 80 years, turtles can outlast them and hit up to 100 years.

 One of the reasons why it’s crucial to know your turtle’s age is to know how long it will be part of your life. If you discover that the turtle you own has a lifespan beyond 80 years, you can prepare how it will be taken care of. You can organize for its existence once you’re gone.

Now that we know why determining a turtle’s age is essential, let us focus on the techniques you can use to estimate how old your pet turtle is.

Ways to Estimate a Turtle’s Age

Here are some of the methods that you can use to estimate the age of your turtle.

Inspecting the Hardness and Rigidity of the Shell

Essentially, a turtle shell hardens as it grows older. One way to determine the stage of growth of your turtle is to inspect the rigidity of its shell.

When a baby turtle is below six months, its carapace feels a little spongy when touched. Furthermore, the younger the turtle, the less compact and rigid the shell is. So when you pass your hands gently over the turtle’s surface, you’ll be able to tell whether a turtle is below six months or not.

However, this technique is only applicable for turtle species with a hard shell when they mature. This technique can’t work for some turtles like the Softshell Turtle since they boast smooth shells even when they’re mature. 

Of course, the smoothness of the shell is not the same in other baby turtles and Softshell Turtles. While the former feels spongy and immature, the latter feels leathery and tough to enhance protection against dangers.

Turtle owners should also understand that a less compact shell may also indicate the presence of nutritional metabolic bone disease, commonly referred to as nutritional secondary hyperparathyroidism (NSHP).

Also, care should be taken when inspecting the shell to avoid injuring the turtle. A slight press on the shell can cause considerable damage exposing the young animal’s internal organs to external danger.

Counting the Rings within the Scutes

Counting the rings on the upper part of the turtle’s shell has become a globally recognized method of determining the age of a turtle. Before we jump straight into the technique, let’s first understand everything about the scutes.

  • What are scutes?

Scutes are the rigid plates that make up the upper part of a turtle’s carapace. They are the rough covers that protect a turtle from any external dangers. The scute is made of keratin, a component that is also present in our hair and nails.

Essentially, as a turtle grows old, it starts forming two rings on the scutes, depending on how well it feeds. Turtles either get large or small rings on the scute. The broader rings indicate that the reptile has lived through a period of sufficient feeding, like in the summer. On the other hand, the smaller and less prominent rings indicate that the animal had gone through a season when food was scarce, such as in the winter.

  • Counting the rings

Every scute boasts wider rings with a specific colour and smaller rings of another color. When you want to calculate the probable age of your pet turtle, you need to count the rings in all the scutes and sum them up. Ensure that you count the rings and not scutes since the latter doesn’t reflect the turtle’s age.

  • Estimating the age

Now that you know how many rings your turtle has, we move to the last step, dividing the value you got by two to get the age. For example, if a turtle has 12 rings, the turtle’s age is approximately around six years since every two rings represent a year.

All turtles, whether in the wild or captivity, have rings on the scutes. However, when the turtle is above 15 years, it becomes daunting to estimate the age since the rings get too close and start crisscrossing.

Sometimes counting the rings can be unreliable since some turtles may fail to eat even when food is surplus and develop smaller rings.

Measuring the Length of the Turtle’s Shell and Weight

It’s common knowledge that turtles reach a particular length when they mature. While some may continue to increase in size after, the growth rate won’t amount to anything substantial.

Therefore, by measuring the size of the turtle’s carapace from the part near the head to the rear part near the tail, you can tell whether your turtle is mature. You can then use this information to approximate its age.

However, it’s crucial to note that for you to use this method, you need to know your turtle species. This is because different species reach sexual maturity at different sizes and ages. For instance, a Red-eared Slider reaches sexual maturity between 5 to 6 years, measuring 10 to 15 cm.

More importantly, you’ll need to know whether your pet turtle is male or female because males and females come in different sizes in many turtle species. 

To know whether your turtle has reached sexual maturity, you need to compare its measurement with a growth chart for its species. If you can’t access the chart from your local turtle sanctuary, you can search for it online or find a book with all the information about this particular species.

By comparing the measurements you got with a growth chart, you can figure out your turtle’s growth stage. For example, the Southern Painted Turtle can’t grow beyond 15 cm. On the other hand, Western Painted Turtles can reach up to 20cm when they mature fully.

Although this method gives you a rough estimate of your turtle’s age, it can give false impressions. First, some turtles can eat more and overgrow than expected. Secondly, female turtles tend to eat more and grow faster than male turtles. Lastly, turtles in captivity tend to mature more quickly than their counterparts in the wild.

Sexual Maturity

When turtles are juveniles, it can be challenging to know their sex. This is because they don’t exude any differences externally. However, when they reach sexual maturity, they start developing various features that help you to differentiate them.

For instance, when male turtles become of age, their tails become longer. This is because the tail is what houses their reproductive organ. Also, the claws on the front flippers enlarge to help them latch onto the females when mating.

When it comes to the female turtles, they don’t have anything outstanding to differentiate them from the males. However, like any other egg-laying animal, female turtles start laying eggs when they attain sexual maturity.  They’ll lay eggs even if there is no male to mate with them.

Therefore, when you start noticing that the male turtles are developing long tails and foreclaws or see that the female turtles have begun laying eggs, this is a sign that they have reached sexual maturity. Since there are records of when various turtle species start laying eggs, you can use them to estimate your turtle’s minimum age.

However, like the rest of the methods, this technique is not 100% accurate. However, it will provide a rough estimate of your turtle’s age.

Visual Inspection

You can also estimate the age of your pet by looking at various visual sides of aging. When turtles get older, their shells change in color and become degraded. This method is best suited for wild turtles because they are more prone to wear and tear.

As turtles age, they get injured and get multiple dents, chips, and scratches on the carapace. Additionally, their head or legs will have scars, and their plastrons will become smoother. The older the turtle is, the smoother the shell. Continuous sunlight, rainfall, and sand can degrade rings, scutes, bumps, and ridges.

Although this method can tell a lot about wild turtles, it can’t say much about captive turtles since they reside in well-maintained ponds or aquariums. Wear and tear and injuries are not expected in captivity. However, with age, turtle’s carapaces become darker and less alluring.

However, visual signs can be misleading since some turtles may have degraded carapaces due to poor nutrition and diet. Nevertheless, it’s still an ideal technique to tell you whether your turtle is fully mature.

Skeletochronology Testing

Skeletochronology is an advanced technology that helps determine the age of turtles when they die. This technique involves counting LAGs (lines of arrested annual growth) in the animal’s skeletal tissue to determine its growth rate and age.

The turtle’s scapula, humerus, and femur bones are studied during these tests to help determine the age. The method has for a long time been used to determine how old sea turtles found dead on the shores of the seas are.

Skeletochronology is considered a more accurate method of determining a turtle’s age than counting rings and visual inspection. Unfortunately, a turtle needs to be dead for this test to be performed.

This type of testing has proved beneficial to marine zoologists and other professionals who want to study sea turtles, mainland turtles, and tortoises.

Tracking the Hatching Date

As mentioned earlier, there is no better way to determine a turtle’s age than to track its hatching date. Knowing the month and year within which your pet turtle was hatched can help you accurately determine a turtle’s age.

The rest of the methods discussed in this write-up may help you estimate the age of a turtle, but not with all certainty. Keeping track of the hatch date is the only way to tell how old a turtle is.

However, unlike the other methods, tracking a turtle’s hatching date is a difficult task. Since turtles have one of the most extended life spans, they often change hands several times. As the turtle moves from one owner to the next, some vital information, such as hatching date and reproduction, can get lost in between. This makes it extremely challenging to know the actual age of a turtle.

Therefore, if you want to know the age of your turtle pet with certainty, you must document the progress from the moment they’ve been hatched. Make sure to pass the records to the next person if you need to let go of your pet turtle. 

Seek Professional Help

If you feel like you have hit a dead rock when determining a turtle’s age, the last option is to ask for professional help. You’ll need to look for a veterinarian officer who specializes in reptiles, especially turtles.

Using their experience and expertise, vets can help estimate your turtle’s age better than you can. If they’ve dealt with turtles from the same species as yours before, they might have extensive knowledge that will help approximate the age even better than an internet search.


Telling how old a turtle is can be very challenging. Obviously, there is no better way to know the age of a turtle than tracking its hatching date. However, this doesn’t mean that you can’t estimate your turtle’s age if you don’t know its hatch date. Over the years, several methods have been devised to help pet owners guess a turtle’s age.

One of the commonly used methods is counting the rings on the turtle’s scutes. This method assumes that every two rings represent an entire year. Unfortunately, the method may be unreliable since turtles can develop more than two rings a year.

The other methods you can use to approximate a turtle’s age include visual inspection, checking sexual maturity, measuring the turtle’s length, and inspecting the hardness of their shells. There is also a more advanced technique of studying the turtle’s bones known as Skeletochronology Testing. Although the method has higher accuracy than the other methods, it is unfortunate that it’s only performed on dead turtles.

You can use these methods to estimate a turtle’s age, but you can always seek professional guidance if none of the techniques seems to work.

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