How To Tell The Age Of A Turtle? [Illustrated Guide]

The information is current and up-to-date in accordance with the latest veterinarian research.

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In this article, I am going to explain how to tell the age of a turtle. let me start by saying that, there is no one reliable way to determine the age of a turtle accurately. There are some ways to guess the age, but these methods are not 100% reliable. If you want to determine the accurate age of your turtle, you’ll have to know when it was born. Otherwise, unfortunately, you can only guess the age of a turtle.

There are basically two methods to guess the age of a turtle. these methods are counting the rings on the turtle’s carapace (upper shell) and comparing the size with another same species of turtle. however, as I have said before, both of these methods are only good at guessing the age of the turtle.

“Counting Rings” method:

In this method, we count the rings on the scutes of the turtle’s upper shell. The scutes are basically the scales that cover the turtle’s carapace. Generally, the rings only develop in times of proper feeding and scarcity of food. In other words, the rings can form when the turtle was properly fed or seriously famished, not only during summer and winter. So, this method can only give a rough estimate of the turtle’s age.

  • You can observe the rings on the scutes of the turtle’s carapace. You can see that the rings alternate between a wider ring and a narrower ring in the scutes. The rings can also alternate between colors. Generally, the wider ring represents the time when the turtle was properly fed, also considered as the summertime. On the other hand, the narrow rings represent the time of scarcity of food, which is also considered as the winter time. So, theoretically, a wide ring and a narrow ring both forms up a whole year. So, if you count all the rings and divide it by 2, you should get a rough estimate of the turtle’s age.
  • Do not count the scutes. You need to count the rings within the scout. In some turtle species, the rings are more visually prominent than the others.
  • After you’ve counted the rings, you just need to divide it by 2. Suppose, you’ve counted 14 rings. Then the turtle’s age should be around 7 years old. However, it is difficult to count the rings after the turtle has passed 15 years, as the rings get closer with age.

“Checking The Size” Method:

Male Plastron Length (mm)Female Plastron Length (mm)Age (Years)
30 to 4030 to 40Newborn
Around 75Around 1305
Around 100Around 16010
A little above 100Around 22530
A little above 100Around 23040
A little above 100Around 23550
Please note that the data considered here are just a general assumption. Actual data can vary depending on the species of the turtle and many other factors.

In this method, we measure the size of the turtle to get a rough estimate of its age. Here’s how this method works:

  • This method is mostly applicable for matured turtles. you need to measure the length of your turtle from tip of the nose to the tail. you can either use a measuring tape or ruler. If you face a hard time to keep the turtle still, a tempting treat can help.
  • Now you need to get your hands on a size chart for the particular species of turtle you are keeping. You can look for a size chart in online or in a library. Make sure you are getting the chart for the exact specific turtle. it is seen that turtles in captivity grow much quicker than in the wild. This quick growth can give a false reading when determining the turtle’s age.
  • Once you got the size chart, compare your turtle’s length in the chart against the age. This method particularly works if your turtle hasn’t reached its full length yet.

Visual signs of age:

Some turtles, especially in the wild, show some visual signs of aging. Though these signs don’t tell the exact age of a turtle, these are helpful to determine whether a turtle has reached maturity or not. For example, in wild, the shell’s condition, as well as its coloration, indicate whether a turtle has reached adulthood or not. In wild, the carapace of older turtles is more worn and torn. The carapace can also have dents and chips. While the plastron can be smooth, there can be scars on the head and legs. Such signs tell that a turtle has reached its matured age, which is approximately 10 to 20 years old.

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These signs are not prominent in captive bred turtles, as the shells of captive-bred turtles do not sustain injuries like wild turtles. So, this method won’t work well for turtles in captivity. Also, some turtles start to get darker as their age increases.

Giving too much priority on the condition of the shell to determine the age is not recommended. A turtle that has lived on poor nutrition will grow a bad shell and can look older than it is actually. Turtles that didn’t have a proper diet for several years can grow a bumpy, rough shell which will give you a false reading of age. So, the visual signs are not 100% reliable when determining the age of a turtle.

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Examining the bones:

While this method is not for any average turtle keepers, scientists have started to use this method for determining the age of sea turtles. The scientific name for this method is skeletochronology. The way this method works is, theoretically some bones in sea turtles produce annual rings. So, by counting this annual rings, we can determine the age of the turtle.

However, a team of investigators under Dr. Brian Wallace from the “Non-profit Sea Turtle Conservation Organization” has revealed that this method produced mixed results. According to Dr. Wallace, this method worked well with some species of the sea turtles, such as Kemp’s Ridley Sea Turtle species. However, it didn’t work on some species like the leatherback sea turtles.

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 How to tell the age of a red-eared slider turtle:

How to tell the age of a red-eared slider turtle

Red-eared slider is one of the most popular pet turtles in the USA. They can easily live for up to 50 years in captivity. It is really difficult to determine the age of a slider turtle unless you know when it has hatched. However, there are some methods which can help you guess the age of the slider turtle. here are the steps to guess the age of a red-eared slider turtle:

  • When the red-eared sliders are hatchlings, they get very bright coloring. The shells are dark green with bright yellow markings all over it. However, the colors start to fade after about 1 year. The dark green color fades into an olive hue. After about 2 years, the red markings beside the ears start to disappear. The shell also turns into a brownish color.
  • Another way to guess the age is by measuring the length of the carapace. If the turtle is just hatched, it’s carapace will be shorter than your thumb. When the turtle is 2 years old, its carapace should be about 4 inches long. By the time the carapace reaches 6 to 8 inches long, the turtle is at least 4 years old. Thus the growth of the carapace continues until it reaches about 12 to 13 inches long.
  • The third way is to observe the turtle’s front and back. Male red-eared sliders start to grow large claws and tail after the age of 2. The claws start to get refined and prickly between the age 2 and 3. After that, the claws get shorter and duller as the turtle continues to age.

How to tell how old a painted turtle is?

How to tell how old a painted turtle is

Like red-eared sliders, painted turtles are also very common and popular in the USA. Here are the steps to guess how old a painted turtle is:

  • You need to turn the painted turtle upside down. It will not be an easy task as turtles hate being upside down, as this is their most vulnerable position. The turtle may hiss or try to bite you. So, take precautions. Handle the turtle gently to avoid any accidents.
  • We need to observe the abdominal area. The abdominal area will likely be in the middle of the plastron, slightly on the lower half. You should see about 8 sections there. There will be two abdominal areas. Choose only the left or the right one.
  • Now you need to count the rings. Each ring represents a complete growth cycle. The first ring should be counted as zero as it is present when the turtle is born.
  • You can guess the age of the turtle on the number of rings. If the abdominal area has 5 rings, then the turtle is likely 4 years old (as you have counted the first ring zero). This is not an exact estimate, rather than an educated guess.
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How to tell how old a snapping turtle is?

How to tell how old a snapping turtle is

Guessing the age of a snapping turtle is very difficult, especially when the turtle is matured. Counting the rings to get an estimated age is a reliable way, but it doesn’t work on matured species. Sometimes, the shell condition and the size also gives a good estimation of the age of the snapping turtle.

  • Many turtle keepers count the growth rings to get an estimated age of the snapping turtle. you can observe the growth rings on the scutes of the snapping turtle. the scutes grow very quickly when there is plenty of food for the turtle. on the contrary, the growth rate of the scutes slows down when there is a scarcity of food. Each ring generally represents an annual cycle. So, if the snapping turtle has 7 rings, it is likely to be 7 years old.
  • Size is also a good way to estimate the age of a snapping turtle. in general, larger snapping turtles are older than the small ones. A recent study by the Tortoise Trust showed that a 10 years old snapping turtle can easily have 7 inches long carapace. Their carapace can get 11 inches long when the turtle reaches 25 years of age. Snapping turtles that are living for 70 to 100 years are likely to have about 18 inches long carapace.
  • The shell gives a very little clue when determining the age of a snapping turtle. it can only tell us whether the snapping turtle is a hatchling or not. Generally, the hatchlings have three ridges on their carapace. As they grow, the ridges start to disappear and the carapace gets smoother. So, if your snapping turtle has a smooth carapace, it is likely to be at least a few years old.

So, this is my detailed guide on how to tell the age of a turtle. Like I have said before, there are no definite ways which can exactly tell a turtle’s age. These methods can only give you a calculated guess of the turtle’s age.

Determining The age of a turtle: infographic

If you want a printable version of this infographic, click here!

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About Author

Muntaseer Rahman started keeping pet turtles back in 2013. He also owns the largest Turtle & Tortoise Facebook community in Bangladesh. These days he is mostly active on Facebook.


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