How To Tell The Age Of A Tortoise? [Chart, Picture]

Have you ever looked at a tortoise and wondered how old it is? Depending on the species, tortoises can live over 100 years. You cannot guess a tortoise’s age just looking at it. Even if it is easy to identify which stage of life they are at, it is not easy to determine their exact age. So, how to tell the age of a tortoise? 

It is only possible to know the exact age of a tortoise if you know when it was born. Otherwise, you can only estimate by examining its shell texture, size, and markings. You can also take the help of an expert to know a tortoise’s age through scientific tests. 

In this article, you will learn a few methods to tell the age of your pet tortoise or a wild tortoise. However, keep in mind that these methods may not always provide the exact age of a tortoise. 

Why It Is Important To Know The Age Of A Tortoise? 

There are many reasons to know how old a tortoise or turtle is. You will understand what food you should feed them according to their age. You will also know what type of behavior to expect. Thus, you will know whether a tortoise is slowing down because of old age or sickness.  

So, by knowing the age of a tortoise, you can provide better living conditions and health care for your pet or wild tortoises. 

Life Cycle of Tortoise 

Like any other animals, tortoises also go through different stages in life. There are four stages in a tortoise’s life. These are:

• Egg/ nesting: Adult female tortoises lay eggs once they become sexually active. Depending on the species, tortoises can lay 1 to 20 eggs in a single clutch. 
• Hatchling: The baby tortoises use their egg tooth to break out from the eggshells. This is a sensitive period for tortoises, as they are most vulnerable in this stage of life. 
• Juvenile: After the hatchling phase. Tortoises reach their juvenile phase. During this time, they start rapidly growing. 
• Adulthood: At the age of 10 to 20 years, tortoises reach their sexual maturity and grow to their full size. Then female tortoises will mate with male tortoises to procreate. 

During these different stages, tortoises go through various behavioral and physical changes, especially their size changes. 

How To Determine The Age Of A Tortoise? 

There are different ways to find out the age of tortoises. Although there are few ways to know the exact age of a tortoise, you can still figure out which stage of life the tortoise is in. 

Most of these methods are easy, and you can do them yourself. However, you will also know about scientific methods for better age estimation of tortoises. 

Learn When The Tortoise Hatched 

If you want to be absolutely sure about a tortoise’s age, you must know when it hatched. It is the only way to know its exact age. 

Breeders of tortoises keep count of the age of the tortoises. If you get a tortoise from a pet store, ask the seller to provide information about your tortoise’s hatching date. 

Use An Age Chart for Tortoise

It is not necessary to know the exact age of a tortoise to provide them with food and care. Knowing at which stage a tortoise is enough. If you do not know the date of a tortoise’s hatching, you can use an age chart for tortoises. You can find out whether your tortoise is mature with the help of the size chart. 

But first, you must know which species of tortoises you have. Then compare it with the size it is expected to reach when it matures. Usually, tortoises reach their maximum size in 10 to 20 years. 

Also, the size of a tortoise is measured by the size of the carapace (The shell). To measure a tortoise, use a measuring tape. Measure the length of the tortoise by holding the measuring tape from one end of the shell to the other end.

After getting the measurement, compare your tortoise size to the ideal mature size according to its species. 

Here is a list of different species of mature tortoises and the size and weight they should have: 

Species of Tortoise	Male Size	Female Size	Weight
Aldabra Tortoise	4 feet	3 feet	350 – 550 pounds
Burmese Mountain Tortoise	2 feet	2 – 2.5 feet	70 –100 pounds
Egyptian Tortoises	3 – 4 inches	4 – 5 inches	105 – 450 grams
Elongated Tortoise	12 inches	12 – 14 inches	7 pounds
Greek Tortoise	5.5 – 6 inches	7 – 10 inches	2 – 5 pounds
Hermann’s Tortoise	7 inches	8 – 9 inches	7 – 9 pounds
Indian Star Tortoise	7  inches	10 inches	3 – 4.9 pounds
Leopard Tortoise	10 – 18 inches	12 – 18 inches	28 – 30 pounds
Marginated Tortoise	12 – 14 inches	10 – 12 inches	9 – 11 pounds
Radiated Tortoise	15 – 16  inches	15 – 16 inches	25 – 30 pounds
Red-Footed Tortoises	11 – 13.5 inches	10 – 11.25 inches	20 – 30 pounds
Russian Tortoise	5 – 7 inches	7 ­– 10 inches	1.5 – 4 pounds
Spider Tortoise	4.5 – 6 inches	5 – 7 inches	200 – 400 grams
Sulcata Tortoise	2.5 – 3.5 feet	2 – 3 feet	80 – 100 pounds
Yellow-Footed Tortoise	15 – 25 inches	14 – inches	25 – 35 pounds

The chart provides an average size and weight for matured tortoises of different species. However, there can be some exceptional cases where tortoises can grow below or above their average size. 

Sexual Maturity 

Like humans, tortoises reach their sexual maturity before they are fully grown. Depending on the species, tortoises can become sexually mature in 4 to 15 years. 

So, if you find female tortoises laying eggs, you can assume they are between 4 to 15 years old, and the same can be said for their male counterparts. In the case of male tortoises, you can tell when they mount on female tortoises for mating. 

Can You Tell A Tortoise’s Age By Its Shell?

There is a misconception about counting the scutes rings on shell to tell the exact age of a tortoise. So, is it really possible? Unfortunately, it is not possible to figure out the exact age of a tortoise from its shell. 

However, a tortoise’s shell gives off enough about the likely age of the tortoise. Therefore, you can learn how to examine the shell to estimate the age of a tortoise. 

Here are a few ways to do that: 

Feel the Shell

You can pick up the tortoise or just put your hands on the shell to feel it. Young tortoises have soft shells. So, tortoises that are less than 6 months old have semi-rigid shells. On the other hand, an adult tortoise will have hard shells. In fact, the shells of tortoises get harder after 6-8 months. 

When you pick up or touch the shell of a tortoise, make sure not to hurt them. Just feel the hardness of the shell with your hand gently. 

The shell or carapace is a part of the tortoise’s bone structure. The spine is connected to it. So, a tortoise can feel the pain when the shell gets damaged. 

Counting Shell Rings

Many people used to think the number of rings reveals the actual age of a tortoise. But this theory has been debunked. However, counting scute rings is still a common method for guessing an approximate age of a tortoise. 

If you look at the shell of a tortoise, you can see oblong patches all over the shell. These patches are known as scutes. Scutes are made of keratin. So, it grows like our fingernails. When the tortoises grow, the scutes also enlarge. As they expand, they form visible rings on the shell. 

Two different kinds of rings appear on the scutes. One is thicker, and the other is thinner. The thicker rings develop during the main annual growth period when a tortoise eats plenty of food. Also, the thinner rings appear annually during a slow growth period. 

Do not make the mistake of counting each ring for a year. According to experts, the best way to calculate a tortoise is by counting a thicker and a thinner ring beside it as one year. 

So, if you see 30 pairs of rings on a shell, you can estimate that the tortoise is more or less 30 years old. 

However, turtles only form thicker rings when they are well-fed. So, a famished tortoise may not form the annual thicker ring even if it gets a year older. Again, food might be available for the tortoise all year round. Thus, it can form two thicker rings annually. 

Besides, the counting ring method becomes unreliable once a tortoise becomes 15 to 20 years old. By then, the rings may form closely, and they can also erode. So, it will not be surprising if you count 30 pairs of rings, but the tortoise is actually 20 or 40 years old instead of 30 years. 

Visual Signs of Aging 

As mentioned before, the roughness and patches of the shell of a wild tortoise can get smoothed because of encountering years of rain and blowing sand. A century-old tortoise will have a smoother and plainer shell compared to a young tortoise. 

Besides, old tortoises become more inactive. They prefer to spend their time lying around on the ground. Their skin also appears to be much wrinkled and scaled than young tortoises.  

Other Methods of Telling Tortoise Age

Apart from measuring the size and texture of the carapace of a tortoise, there are some other ways to know the age of a tortoise. But these methods are mostly scientific, and only experts can use these methods. 

Take The Help Of A Vet

A veterinarian is surely more skilled in finding out animal ages. Of course, a vet uses the same methods mentioned above to examine a tortoise. But they will also take a blood sample of your tortoise for tests. 

A blood test will help get a metabolic profile of the tortoise to have an estimated age. It is possible to make a better age assumption with the blood result and other physical signs.  

Tagging

Wild tortoises are difficult to track. So, scientists often use the ‘mark and recapture’ method to estimate their age. 

They capture tortoises not more than two years old. Then the scientists put a harmless mark on their carapace and let them go. This way, the tortoises are tracked for years. 

Examine the Fungal Growth

Tortoises in the wild can have fungus growing on them. If you see a tortoise with lots of fungal growth, you can assume it is an adult or old tortoise. 

Scientists take a sample of the fungus from the shell to know how old the tortoise is. 

Skeletochronology Testing

The skeleton or bone structure of a tortoise can tell a lot about its age. Examining the growth layers on the bones is called skeletochronology. This method can provide pretty accurate results. 

Unfortunately, the skeletochronology test cannot be done on tortoises while they are alive. Hence, scientists use this method on deceased tortoises to know at what age they died.  

What Is The Average Life Span Of Different Species Of Tortoises?

Tortoises can live a long life if the conditions are in their favor. An Aldabra giant tortoise named Adwaita lived about 250 years. Also, the Galápagos tortoises are well-known for living over 150 years. 

Even though all tortoises do not live for centuries, they still live quite a long life. On average, different species of tortoises can live 50 to 100 years. 

Here is a list of life expectancy of different species of Tortoises:

Species of Tortoise	Lifespan
Aldabra Tortoise	80 to 120 years
Elongated Tortoise	40 to 50 years
Greek Tortoise	125+ years
Hermann’s Tortoise	60 to 80 years
Indian Star Tortoise	35 to 80 years
Leopard Tortoise	30 to 75 years
Marginated Tortoise	100 to 140 years
Red-Footed Tortoises	50 to 60 years
Russian Tortoise	50+ years
Sulcata Tortoise	80 to 150 years

 The table above shows the typical life expectancy of different species of tortoises. Tortoise can outlive their life expectancy if they live in a safe environment with plenty of food and care. 

Conclusion 

By now, you should have learned how to tell the age of a tortoise. As you can see, the only way to be sure about a tortoise’s age is if you know when they hatched. Other methods cannot give the exact age. However, these methods can tell you the approximate age of a tortoise, which is enough to provide the support and care it needs.