How To Tell If Tortoise Eggs Are Fertile

How To Tell If Tortoise Eggs Are Fertile 

If you’re a tortoise owner, you may be curious about whether your tortoise eggs are fertile or not. Determining the fertility of tortoise eggs can be a bit of a mystery, but there are a few methods you can use to find out.

So, how to tell if tortoise eggs are fertile? The first method is by candling. This is observing the eggs regularly by shining light on them to observe the inside of the egg. You’ll notice a distinct sign of an embryo if it’s fertile. Also, the appearance (pinkish or reddish color shows it’s fertile) and veins present in the egg are other methods too. 

In this article, we’ll discuss in detail how to tell if your tortoise eggs are fertile. 

How To Tell If Tortoise Eggs Are Fertile?


Determining the fertility of tortoise eggs can be challenging, as the signs can be subtle and vary. Note that it’s possible to differentiate the fertile eggs shortly after the tortoise has laid them. 

How To Tell If Tortoise Eggs Are Fertile

Nevertheless, complete certainty requires a waiting period of 2 to 3 days. Below is how to tell if the tortoise eggs are fertile.   


This process involves shining a light source through the egg to observe the interior. Look for these vital cues.

  • Signs of embryo development.  Fertile eggs show a network of blood vessels.
  • Dark spots indicate that the embryo is growing. 

Remember, it’s essential you perform candling in a dark room to get a clear view of the internal changes.


When candled, fertile eggs have a reddish or pinkish hue due to the presence of blood vessels and the developing embryo. Conversely, when externally viewed, these eggs appear white and opaque. 

Therefore, within a span of 2-3 days, you’ll notice these eggs begin displaying indicators of progress, such as a chalky appearance.

Egg Texture and Firmness

Apply slight pressure to identify the subtle firmness of fertile eggs versus infertile ones. Note that the fertile one undergoes gradual moisture loss as the embryo develops.

Handle with care, especially in smaller eggs, to ensure they remain intact throughout your assessment process.

Tortoise Egg Texture and Firmness

Visualizing Veins

Look for vein patterns – small red dots that mature into prominent veins. Typically, these veins appear within 5-7 days after the female tortoise lays her eggs, indicating fertility.

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Incubation Period

Each tortoise species has a unique incubation period. Match the passing days to this duration for clues. Fertile eggs generally require 70 to 120 days, varying by species. If this period elapses with no developments, it hints at potential infertility.

Process Female Tortoises Fertilize Their Eggs

Process Female Tortoises Fertilize Their Eggs

Here is a process of how eggs are fertilized.

  1. Mating Preparation: As spring arrives and male tortoises emerge from hibernation, they actively search for female companions to mate with.
  2. Cloacal Connection: When a compatible male is found, the courtship begins. The male nudges the female, and she responds by extending her cloaca.
  3. Transfer of Sperm and fertilization: Through ejaculation, male sperm makes its journey to the female’s reproductive opening.
  4. Eggshell Formation and Pore Sealing: After fertilization, the egg moves down the oviduct to the shell gland, where eggshell formation occurs. This shell is vital for embryo protection and maintaining hydration.

The shell pores are sealed to serve this specific function just before the eggs are laid.

How To Keep Tortoise Eggs Fertile?

How To Keep Tortoise Eggs Fertile

Here are steps that will help to keep tortoise eggs fertile for successful hatching.

  • Step 1. Allow the eggs to remain undisturbed in the nest for a period of 2 to 3 days.
  • Step 2. Monitor the eggs’ progress by candling them every 3 to 4 days to observe the embryo.
  • Step 3. Carefully remove discolored eggs or eggs with developed mold.
  • Step 4. Mark each egg with a non-toxic pencil to keep track of its orientation during incubation.
  • Step 5. Handle eggs minimally and with clean hands.
  • Step 6. Place eggs in the incubation medium with the same orientation they were laid.
  • Step 7. Use a suitable incubation medium such as vermiculite, perlite, or a specialized reptile incubation substrate.
  • Step 8. Maintain proper humidity levels in the incubation medium, usually around 80%-90%, to prevent dehydration of the eggs.
  • Step 9. Keep eggs at the appropriate temperature for the specific tortoise species. This can vary, but a general range is often around 80°-90°F (26°-32°C).
  • Step 10. Be patient and observe the eggs regularly. Avoid opening the incubator unnecessarily to avoid stressing the embryos.
  • Step 11. Keep a record of when eggs were laid and candled and any changes you make to the incubation conditions.
  • Step 12. If you need more clarification, seek advice from experienced tortoise breeders or reptile veterinarians.
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Here are questions people also asked on how to tell if tortoise eggs are fertile.

Q1. Can a female tortoise lay eggs without mating? 

Yes, Female tortoises can reproduce asexually, laying viable but unhatchable eggs. Eggs from non-mating females won’t hatch. Tortoises lay eggs annually, with or without mating.

Q2. How many eggs does a tortoise lay?

Tortoise egg production varies due to species, size, and age. Larger species like the Sulcata lay 15-30 eggs 2-5 times yearly. Healthy females usually lay 4-8 eggs per cycle, while Angulate tortoises lay 1-7 times annually.

Q3. What age do tortoises lay eggs? 

Breeding for wild tortoises usually commences around 15-20 years of age, while well-fed pet tortoises reach this stage at approximately half that age.

Final Words

Determining the fertility of tortoise eggs is important and identifying fertile eggs becomes feasible. This is carried out by observing egg appearance and maintaining optimal incubation conditions. Also, candling offers a deeper insight, showcasing embryo development or blood vessels by shining a light on the egg.

Patience during the incubation period is essential for accurate assessment. Seeking expert guidance adds an extra layer of assurance. Ultimately, mastering these methods enhances understanding and kindles excitement for the possibility of welcoming vibrant tortoise hatchlings into the world.

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