Originally Posted by
Grumpy
From the referenced article:
Because they are ectothermic, temperature affects a variety of biological functions in painted turtles, including egg development. In fact, temperatures can even affect the growth rate of the individuals after they hatch. To ensure proper development, you must keep painted turtle eggs between 78 and 86 degrees Fahrenheit. Within this range of tolerable temperatures, the eggs develop more quickly in warmer temperatures than cooler temperatures, but incubation temperature also influences other biological process; specifically, the determination of the turtle’s sex.
This phenomenon -- known to scientists as temperature dependent sex determination -- is common to many species, notably turtles and geckos. This means that you can decide which sex you want the hatchlings to be. Those incubated at the upper end of the acceptable range become females, while incubation temperatures at the lower end of the range produce males. Intermediate temperatures of about 84 degrees yield a mix of both sexes.
Interesting, we have a large population of western painted turtles at our cabin in northern Idaho, and they have been busy traveling across lawns and roads away from the Lake to lay eggs over the last couple of weeks. Our soil temperatures are much cooler that 78 to 86 degrees so apparently our western turtles have adapted. Thanks for sharing your turtle egg troubles.