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How to tell turtles apart?

Telling your pet turtles appart when there are two of the same species can be a little tough sometimes. If the turtles are different species, it’s obviously much easier.

In this article, we will be looking at how to tell turtles from the same species apart.  Except looking for physical differences, the easiest way to tell turtles apart is by marking them. There are different types of marks that can be done.

It is not advisable to use any kind of paint that you just have laying around, as this could be toxic for the turtle.

1. Using Physical Inspection to Tell Them Apart

No matter how similar any two turtles are, they are never perfectly the same. There will be small differences that you can use to tell them apart.

Shell differences

Shell color differences
Note the shell differences on these two tortoises, the colors, the shapes, and the patters.

The shells and markings differ from one turtle to another. This is particularly true of the underside. Physically inspecting and memorizing the differences should help you easily identify them.

If you don’t think you can memorize these differences, why not take a picture and label it with the turtle’s name. If you are ever confused about who is who, you can simply compare them to the photographs. You can also sketch the shells and make notes on easily distinguishable features.


Most turtles will have a natural mark that you can use to distinguish them. This can be a scar or a nick, a malformed scute, and color splotches.

In the above image you can see the markings are slightly different, the legs, though retracted on one are different as well as features such as nails.


Going by color also works however, it is necessary to note that turtles change color as they grow. Most turtles will darken in color as they reach maturity and over the years.

In the image above you can see the top tortoise has lighter dark marks while the bottom has a more pronounce black outline of each raised area.

Physical differences – Gender (Boy or Girl)

Male water turtles will have front nails that are much longer compared to a females. Another feature is their tails will be longer and thinnger.

Male sliders are also much smaller than females which can be a dead giveaway.

See your guide on identifying what gender your turtle is for more in depth tips.

2. Making Physical Permanent Marks (not recommended)

I do not recommend this as the shell is a living organ of the turtle. There is always a risk of severely injuring the turtle.

Here the marks/cuts are made to the marginal scutes. Tiny v-shaped cutes are made as shown in the picture below –

Biologists use this series of marks to ID turtles in the wild. Here, bridge marginal scutes are not marked.

The marks are made to the posterior dorsal scutes.

3. Using Paint Or Marker To Mark Your Turtle And Tell Them Apart

When it comes to painting your turtle to tell them apart, care needs to be taken. Most paints are hazardous to chelonians. Some paints contain fumes and apart from that the paint can seep into the turtle’s bloodstream and lead to poisoning.

Option 1: Use A Paint Marker

Materials Needed

Some paints are nontoxic and work well for marking chelonians (both aquatic turtles and tortoises). The one I most recommend is the Markal paint markers. These markers are easy to use and come in a variety of colors, they are UV resistant and weather resistant and can last for years. On turtles, the mark will last until their next scute shed.

This can be in a few weeks to even a few months. Tortoises don’t shed their scutes and as such will last longer. These markers are even used by biologists to mark wild turtles in order to keep track of their numbers and movements.

Torotoise with an old injury
Example of tortoise with old injury marked on it’s shell with number 194

When using a non-toxic paint on the turtle make a small mark. Nothing big. Covering a large surface will inhibit the turtle’s ability to absorb sunlight/UV light. The turtle needs this to synthesize vitamin D3, which is an essential nutrient.

Most people make a tiny dot in the center of the scutes. These marks are easily seen even from afar. 

Option 2: Use Other Commonly Found Items

Materials You May Need

  • Duct Tape
  • Permanent Marker
  • Nail Polish

Other objects can also be used as short-term solutions. 

Duct Tape: You can use a small piece of duct tape. If you have several turtles you can mark the duct tape with paint before sticking it onto the turtle’s back.

Permanent Marker: Normal permanent marker also works well. These will fade much faster than a Markal marker but they can get the job done. A small mark should do, nothing elaborate.

Nail Polish: I don’t recommend these but they should work for a while. They are prone to chipping and coming off much quicker as well. Some might also contain chemicals that can be harmful to the turtle.


Here are some frequently asked questions. These should provide you with extra information. Topics addressed include removing paint marks, why you shouldn’t paint your turtle as well as harmful chemicals to avoid marking your turtle with.

How do you remove paint marks from your turtle?

Marks from a Markal marker will last for years, several years. However since turtles shed their scutes, this should last several months. Since it is water-resistant and UV resistant, don’t expect it to come off using water. Use a solvent to remove the mark. Solvents can be used include turpentine, mineral spirits, and paint thinner.

These solvents can be easily found. Dip a toothbrush with soft bristles in the solvent and then gently scrub the paint away. Saturate a clean cloth with the solvent and wipe loose paint off. The mark should come out with ease.

Why shouldn’t you paint the turtle’s shell?

Making a small mark using nontoxic paint is fine but you shouldn’t paint the turtle’s shell even with non-toxic paint. Doing this can hinder the turtle’s ability to absorb ultraviolet light. Turtles require a healthy dose of UV light (UVA and UVB) daily. This is why turtles spend several hours basking each day.

The carapace is the widest part of the turtle and it absorbs most of the UV radiation needed. Covering up this surface will seriously affect the turtle negatively.

Why shouldn’t you use regular house paint or nail polish?

The fumes from the paint can cause respiratory problems; the chemicals can also seep into the bloodstream and harm the turtles. Chemicals such as camphor, butyl acetate, and acetone are all toxic to the turtle. If you must, a bit of nail polish should be okay. However, this will fade faster than a Markal marker.

Apart from regular house paints and other paints. Xylene-based paint pens should not be used. Xylene is toxic to most turtle species. This chemical can alter their behavior.


Just give it time you will be able to tell apart all your turtles including those from the same species. However, if you need to quickly tell them apart, here are some techniques to use.

You can use paint or a marker to mark a scute. This mark may last just a few weeks as turtles tend to shed the outer layer of their scutes. Regardless, this should allow you to easily identify each turtle immediately.

Physically inspecting the turtles is another route to take. You can take note of unique features such as scars or nicks, malformed scutes, and color splotches. You can also take labeled photos of the turtles then you can compare the turtle to the pictures if you ever have difficulties telling them apart.

If you have any questions or extra information, a comment is welcomed.

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Terre' Trail

Friday 15th of October 2021

I have a small turtle that I have NO IDEA what kind he is - is there anywhere I can send a pic and have someone let me know?