How To Tell If Tortoise Eggs Are Fertile?

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

Tortoises are sexually active and lay eggs almost every year. But are all the laid eggs fertile? How can you determine a fertile egg?

The fertile eggs have characteristics like:

  • Just-laid eggs will be pink or red due to the prominent blood vessels.
  • Within 5 – 7 days of incubation, veins can be spotted on the eggshells.
  • The entire egg will be covered with white patches or chalk.
  • Embryo development can be seen with candling.

Find the most common questions and answers on tortoise egg fertility below.

Key Takeaways

  • Fertile eggs contain blood vessels and veins. Chalking is also a sign that the eggs are in good health.
  • Candling the eggs every 3 – 4 days will show embryo development.
  • Infertile eggs do not chalk and rot within a week or so.

5 Signs That Your Tortoise Eggs Are Fertile

Multiple tricks are available to determine whether the tortoise eggs are fertile. In fact, it is possible to distinguish the fertile eggs a few hours after the tortoise has laid them. But yes, wait for 2 – 3 days for 100% confirmation.

Go through the tortoise fertility check tests below,

1. Look At The Color

The just-laid eggs are generally red or pink in color due to the blood vessels. Right after fertilization in the oviduct tube, the eggs require a continuous supply of nutrients. The blood vessels ensure an uninterrupted supply-chain relationship.

Remember, only the fertilized eggs will appear red or pink for a short period. You can not spot the embryo in such a state. As time passes, the eggs will turn white with a blue hue.

2. Fertilized Eggs Have Veins

You will notice veins only in fertile eggs after 5 – 7 days of incubation. As the embryo starts to develop, the veins stretch out around it like a dark spider web. The veins are first visible on both the top and bottom of the eggs, which then extend towards the center.

3. Spot The Embryo

An embryo is visible after a few weeks of incubation. For some clutches, it can take a month for embryo development.

When you candle the eggs, the embryo will appear as a black dot. You can even spot the movement of the embryo inside. Soon the embryo will develop bigger, filling out the entire egg shape.

No embryo means that the egg is infertile.

4. Chalking Indicates Fertile Eggs

Just-laid tortoise eggs are fragile and have a squashy texture. After 2 – 3 days, the eggs will show some development signs with chalking or shell whitening. The term itself justifies the meaning, but let me explain it in simple terms.

Chalking (the first stage of egg development) is nothing but the growth of white patches on the eggshells. These white spots expand quickly and multiply in no time. Soon the whole egg is covered with white patches, and the shell gets stronger.

Unfortunately, the just-laid eggs are always at risk of mold attack. The fungus can also leave white patches all over the egg. Newbies often mistake mold attacks for chalking, which can ruin the entire clutch. Therefore, talk to an expert to confirm the good health of the eggs.

5. Candling: The Ultimate Trick

While candling can 100% confirm the fertility of the eggs, you must wait a week or so before carrying out this test. Candling is nothing but observing the embryo’s development with a regular flashlight.

Well, there are some rules to maintain while candling tortoise eggs. Such as,

  • Do not mess up the orientation of the eggs, which means you can not shake or turn them over. Remember, candling does not require picking up the eggs. A little shake may drown the embryo, detaching it from the shell and killing it at the end.
  • Take the incubator or the egg box in a dark room. Close the blinds to make the room pitch black.
  • Next, use a regular flashlight and press it gently against the eggs. You can not see the embryo and the blood vessels clearly.
  • Candle the eggs every 3 – 4 days for regular observation. However, daily candling can disturb the hatching process.

Do Tortoises Lay Infertile Eggs?

Some owners have complained that their tortoises have laid eggs without any mating. I know this may sound like a miracle, but wait. Experts say female tortoises can store the male partner’s sperm and fertilize their eggs in the following years. Well, it explains the sudden nesting.

However, here is a twist. The claims are that the clutches without proper mating have a high risk of infertility. This statement is not entirely true.

Well, of course, female tortoises can store sperm for more than 4 years. But as time passes, the chances of expelling fertile eggs get lower.

Furthermore, sometimes tortoises lay fertile and healthy clutches. But because of the external pressure and environment, the eggs go infertile. Some circumstances are,

  • Tempering with the egg orientation
  • Infected eggs
  • Desiccation of the egg
  • Improper incubation temperature and humidity
  • Detached yolk from the shell, etc.

How Do Female Tortoises Fertilize Their Eggs?

In spring, right after hibernation, the male tortoises seek a female partner for mating. During intercourse, the male penetrates his penis into the female’s cloaca. As the male ejaculates, his sperm travels to the female’s olva.

Only the fertile ovum will move to the oviduct tube. There, the egg white will surround the ovum as a protection layer.

In the next stage, the eggshells are formed in the shell gland. The primary function of this shell is to prevent bacterial attacks on the embryo and keep the ovum hydrated. The shell pores are closed for this purpose right before the eggs are laid.

How To Keep Tortoise Eggs Fertile?

Of course, you can not guarantee the fertility of any egg for 100%. But there is no harm in trying to maintain the good health of the clutch. Some effective tips are,

  • Do not move the eggs from the nest for 2 – 3 days.
  • Candle the eggs every 3 – 4 days to track embryo development.
  • Never shake the eggs or change their orientation in any circumstances.
  • Look for any mold or bacterial attack on the eggs.
  • If you find an infected egg, separate it immediately.
  • Keep an eye on the temperature and humidity of the incubator.
  • Consult a vet regularly.

How To Hatch Tortoise Eggs Successfully?

In the wild, mother nature takes care of the eggs, and the entire clutch hatches on time. But in captivity, you can not recreate the wild soil pressure, temperature, or humidity inside the nesting box. Therefore, you must take action to hatch the eggs in a homemade or commercial incubator.

Here are the steps to hatch tortoise eggs successfully,

  • Use a spoon to dig out the eggs from the nesting box after 2 – 3 days. One clutch contains 6 – 8 eggs on average.
  • Brush off the dirt from the eggs and transfer them to the incubator.
  • Draw a mark on the top of each egg to avoid messing up their orientations.
  • The incubator temperature range should be between 77F to 95F, which changes with species. Install a thermometer to track the inside temperature. Generally, a low temperature yields male tortoises, and an elevated temperature produces female tortoises.
  • Again, there must be enough moisture present in the incubator. Usually, 80% humidity is recommended for successful hatching.
  • Depending on the species, tortoise eggs will hatch within 70 – 120 days. Some tortoise hatchlings may come out earlier than this timeline. For example, the incubation period for Hermann’s tortoise is 53 – 100 days.

Tortoise Egg Incubator Complications

You may face some complications when incubating the tortoise eggs. Such as,

1. Eggs Do Not Chalk

As mentioned, chalking is the first stage of egg development. If your tortoise eggs do not chalk, they are surely infertile.

2. Chalking But No Embryo Or Veins

Well, candling the eggs allows us to detect the dark black spot inside the eggs. The dot or the embryo ensures that the eggs are fertile.

However, sometimes, you may notice the eggs chalking, but there is no embryo inside. Such a situation indicates that the eggs are infertile. Lack of calcium in the eggs or an improper incubator environment is responsible for this infertility.

3. Reverse Chalking

The eggs may start to shed due to environmental factors or any unknown reasons. As a result, the white eggs will take a pinkish tone. Unfortunately, this means that the egg is ruined.

4. Egg Explosion

Well, your infertile eggs can explode into pieces at any moment. If you do not throw away the infertile eggs, they will rot, inviting bacterial growth. These microorganisms produce hydrogen sulfide gas as a byproduct.

Accumulated hydrogen sulfide can create pressure inside the eggs, forcing them to pop like a balloon.

Before You Go…

In captivity, owners must take responsibility for hatching the tortoise eggs. It is because you can not replicate the wild nesting environment indoors so precisely. Go through the below article to get an ultimate tortoise egg care guide.

Tortoise Egg Care Guide [Common Questions Answered]

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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