Tortoise Egg Incubation
Incubating tortoise eggs is an exciting adventure. There are many variables with tortoise egg incubation, mainly due to the fact that based on the specific breed, you may have a wide range of time frames with hatching. Also, it is common for some eggs to take much longer to hatch than others, even though they are still viable.
It is crucial that you be very attentive and careful when recovering eggs. Sometimes the dirt in the nest can be packed down rather tightly, so you will need to be careful to avoid breaking your eggs. Often tools like a clean toothbrush, spoon, and other small utensils are used to help move the dirt away from the eggs so you can collect them more easily.
Like poultry incubation, you will want to put an "X" or other identifying indicator on the top of each egg. With birds this is so you can keep track of the ones you have turned. For tortoise egg incubation, it is for the opposite reason- you make the mark so you can avoid turning them! Turning tortoise eggs can result in death of the embryo, so it is very important to keep this in mind the entire time you are incubating.
Selecting Incubation Method
Turtles and tortoises can lay either soft or hard shelled eggs, depending on their breed. Tortoises from dry regions typically lay hard shelled eggs, while box and water turtles lay soft-shelled eggs. Harder shelled eggs can be incubated using low humidity, while soft eggs need a high humidity method.
Either way, you will want to be able to maintain a consistent temperature and humidity that is appropriate for your egg type.
Temperature for Tortoise Incubation
Some types of tortoise eggs can be subject to Environmental Sex Determination (ESD). This means that the environment in which they are incubated can help determine their gender. Lower temps produce males, higher temps for females.
The temperature not only impacts the gender of the egg, it also effects the incubation time. The average is 8-11 weeks for most turtle and tortoise species, however the lower the temp, the longer it takes. So if you are temp sexing, looking for mostly males, it will take you longer to hatch your eggs than if you are looking for mixed or all females.
The temperature gradient for incubating tortoise eggs is very large- anwyere from 85 degrees F to 90 degrees F should do the trick.
Humidity for Tortoise Incubation
Humidity is much more important for soft shelled eggs than for hard shelled eggs. Since most tortoise eggs are of the hard shelled variety, we will focus more on that here.
Humidity for tortoise eggs should be at about 70%. Many breeders report that they don't use a hygrometer, but for someone who is less experienced at understanding the signs of humidity that is too low (pitting, collapsing of the eggs) or humidity that is too high (excess moisture, bacteria growth), we definitely recommend picking up a hygrometer to monitor and maintain your humidity.
Setting up your Incubator
As with any incubation project, we encourage you to set-up your incubator atleast 24-48 hours prior to placing eggs inside. This gives you the opportunity to make sure your unit is thoroughly cleaned and sterilized, as well as make sure all components are working properly. You should double check your temperature and humidity and let the device regulate before placing your eggs inside.
You will then need to periodically check your eggs, about once an hour for the first few hours, as the temp and humidity will change with the addition of the eggs to the unit. You may then need to dial your temp up or down slightly to account for more mass inside the unit.
For the first time breeder, incubating tortoise eggs can be ominous, but it is extremely rewarding. Many breeds of tortoise are very hardy and will thus hatch even without ideal incubation circumstances. However, anything you can do to improve your incubation equipment and process will only improve your chances of having a more successful hatch.