Review: Abdel Rahman El Gamal (Founder of the website)
In most animals, the sex is determined by biological sex determination mechanisms (e.g. sex chromosomes). However, in sea turtles, the matter is different where the sex is determined by temperature during egg incubation.
Typically, turtle female leaves the water and comes to the shore where she lays and buries her clutch of eggs in a sandy nest which she digs.
Depending on the turtle species, when the temperature within the sandy nest is about 28-29 degrees Celsius, the embryos of sea turtle embryos develop into almost equal number of male and female baby turtle. On the other hand, the baby turtles produced upon warmer incubation temperatures are skewed to females while the incubation at lower temperature results in turtle offspring predominated by male hatchlings. It may worth mentioning that the difference between the influencing hotter and cooler temperature is only a few degrees.
The influence of temperature goes beyond the speed of hatching as well as the sex ratio creating more concern regarding the global warming. In fact, many scientists expressed their concern regarding the expected predominance of baby turtles by females as a result of rising global temperatures and warmer sand. This concern is supported by reports on the born sea turtles in northern Australia that has been very much dominated by females. The same is true in regard to the findings of a study where as much as 99 percent of baby green sea turtles in warm equatorial regions are females.