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How To Tell The Age of a Tortoise: A Step-By-Step Guide

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By Nicole Cosgrove

indian star tortoise looking at the camera

If you’re a tortoise enthusiast, an aspiring pet owner, or just naturally curious, understanding how to tell the age of a tortoise can be a fascinating subject.

Not only does it give you an insight into your pet’s stage in life, but it can also help guide proper care and inform breeding practices. Here’s a step-by-step guide on determining the age of a tortoise.

Before You Start: Understanding the Basics

While it’s virtually impossible to know a tortoise’s exact age unless you know the hatch date, there are, thankfully, several methods to help estimate it.

From examining the tortoise’s shell to observing behavioral characteristics, these techniques can provide a range of years rather than a precise age. Some methods require a hands-on approach, while others involve a visual analysis or scientific procedure.

  • Know When the Tortoise Hatched: The surest way to know a tortoise’s exact age is to know its hatch date. This information can usually be obtained from breeders or pet stores, as they keep track of the hatching dates of the tortoises they sell. If you have this information, the mystery of your tortoise’s age is easily solved.
  • Sexual Maturity—A Clue to Age: Like many species, tortoises reach sexual maturity before they’re fully grown. Depending on the species, tortoises can become sexually mature between 4 and 15 years. If a female tortoise is laying eggs or a male is displaying mating behaviors, it’s likely they’re within this age range.
  • Examining the Shell: Can It Tell the Age? While the notion of counting the scute rings on a tortoise’s shell to determine its age is a myth, the shell can give a general idea about the tortoise’s stage of life.
Marginated Tortoise on the grass
Image Credit: Joel Mathey, Unsplash

Step-By-Step Guide to Tell the Age of a Tortoise

1. Feel the Shell

Touching the shell can provide valuable insights. Young tortoises, particularly those less than 6 months old, have softer, semi-rigid shells, whereas adult tortoises have hard ones. When handling the tortoise, remember to be gentle to avoid causing any harm or discomfort.

2. Look for Signs of Aging on the Shell

With time, the shell of a wild tortoise can smooth out due to environmental factors like rain and wind-blown sand. Older tortoises tend to have smoother, less detailed shells compared to their younger counterparts. However, if the tortoise has been in captivity for most of its life, this might not be the best method to tell the age.

Kleinmann's tortoise (Testudo kleinmanni), also called commonly the Egyptian tortoise
Image Credit: Michal Sloviak,Shutterstock

3. Behavioral Indicators of Age

Observing the behavior of a tortoise can provide clues about its age. Older tortoises are generally less active, often spending their time resting. Also, their skin appears more wrinkled and scaled than that of younger tortoises.

4. Seek Help From a Vet

If you’re unsure about your tortoise’s age or want a more accurate estimation, a veterinarian can help. They might use similar methods discussed here, but they can also perform blood tests to create a metabolic profile that, along with other physical signs, can help estimate the tortoise’s age more accurately.

veterinarians examining a healed tortoise
Image Credit: Gorodenkoff, Shutterstock

Scientific Methods: Beyond the Basics

If you’re dealing with wild tortoises or need a more precise age determination, scientific methods are used. The following are the most effective ways to best tell its age:

1. Tagging

Scientists have developed a systematic “mark and recapture” method for studying wild tortoises and estimating their age. This method involves capturing tortoises, typically those not over two years old, and placing a harmless, durable mark on their carapace or upper shell. These tortoises are then released back into the wild.

By periodically recapturing these marked tortoises over the years, scientists can track their growth rate and gain a reliable estimate of their age. The advantage of this method is that it doesn’t harm or cause distress to the tortoise, making it an ethically sound approach for scientific study.

sulcata tortoise in a vet clinic
Image Credit: thirawatana phaisalratana, Shutterstock

2. Fungal Growth Examination

It’s quite common for wild tortoises to have fungus growing on their shells. The extent and type of this fungal growth can provide clues about the tortoise’s age. Scientists can collect a sample of this fungus and examine it under laboratory conditions to estimate the tortoise’s age.

Factors such as the type of fungus, its growth rate, and the environmental conditions can impact the accuracy of this method. However, when used in conjunction with other age-determining techniques, the examination of fungal growth can provide a more complete picture of a tortoise’s age.

3. Skeletochronology Testing

Skeletochronology is a method of age determination based on the analysis of the growth layers in bones. These growth layers, much like the shell ring counting method, can indicate the age of a tortoise. By examining these layers under a microscope, scientists can count them and make a fairly accurate estimation of the tortoise’s age.

However, there’s a significant caveat to this method: it can only be performed on deceased tortoises. That’s because the process involves examining the bones, which requires dissection. Therefore, skeletochronology is primarily used in post-mortem studies or historical research where the tortoise’s remains are already available.

Marginated tortoise (Testudo marginata) walking
Image Credit: Rudmer Zwerver, Shutterstock


Telling the age of a tortoise is not a straightforward task and requires a combination of methods for a reliable estimation. Still, whether you’re using your hands or eyes or seeking professional help, understanding your tortoise’s age can be a rewarding experience that enhances your connection with your pet.

Featured Image Credit: Lakeview Images, Shutterstock

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