The most mentioned environmental parameter, influencing the development of the embryo of a tortoise is the temperature of the egg during the development. Successful breeding is only possible within a specific temperature range. For a constant incubation temperature below 23°C and above 34°C the embryo mortality rate for Testudo hermanni boettgeri is 100%.
Below the results of measured incubation periods for constant incubation temperatures are shown. The drawn curve is based on regression analysis of a total of 282 data for Testudo hermanni in the range of 24 to 34°C. The incubation period is defined as the time interval between ovi position and emergence of the full grown hatchling.