As of right now the majority of all out dated and up to date information on spotted turtles as well as most chelonians does state that sex is determined by incubation temperature. There are so many different personal experiences on record but most information on the subject is exchanged only through word of mouth. There still is not enough literature on sex determination as well as any other data on turtles in general. As a rule it is said that the higher the temperature will produce females, and the lower the temperature will produce males, in between will give you a mixture of both. I have experimented with my own captive animals and have used different incubation techniques along with various incubation mediums. Two years ago I hatched serveral Northern Diamondback Terrapins from my group that I purposely incubated at a shocking 90 degrees. I kept one hatchling back to see what it would result in and surprisingly it is a male. There could be so many factors as to why this happened though. Was there a fluctuation in the overall temperature in the incubator durring the sex determining stage of the embryo? I have no idea. I did also notice that most of my spotted and north american wood turtle eggs did not survive such a high temperature while the diamondback and eastern box turtle eggs did. Since that year my eggs are set for 87 degrees for females and 75 degrees for males in seperate incubators. A pair of spotted turtles I hatched in 2003 that are now with a friend have recently been determined females and they were set at 86 degrees. One of the most interesting theories is how north american wood turtles do not apply to sex determined by temperature. They use chromosomes like humans that decide their sex. I have hatched out both sexes every year since 2002 and keep the eggs at 87 degrees. They hatch rather quickly in 43 to 61 days and have no imperfections at hatching. When incubated at higher temperatures my spotted and diamondback eggs tend to come out with extra scutes while the box turtles only do sometimes and the woods almost never do. In field research it is known to find more males of a given species if the habitat is under a canopy where sunlight is not as strong as in open areas. If the habitat is more exposed to the sun, females are found in larger numbers. This is however not always the case, which is one of the many reasons why chelonian research is ongoing and poorly understood. So many factors condradict each other, and the best way to learn in my opinion is personal experience. The only year I ever lost a significant amount of eggs is when I really pushed the temperature up too high, other than that I hatch decent numbers of various species of emydid turtles every year. I'm sure you will talk to others who have different results than I do and I think personal experience really needs to be shared more often because lets face it, captive breeding efforts are about the only way to save our world's turtles and tortoises as long as native habitats are still being destroyed.

-Chris

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