We all know that the temperature of the nest affects the gender of turtle hatchlings while the eggs are still buried in the sand. Researchers have recently discovered another factor that impacts on the hatchlings' gender—where they are positioned within the egg.
A new study has revealed that while still in their shells, turtle embryos sometimes can influence their own gender.
The researchers, from Chinese Academy of Sciences (CAS) and Macquarie University, discovered that the embryos would move around to find different temperatures within the egg.
In the course of their research—which involved incubating turtle eggs at various temperatures in both the lab and outdoor ponds—they found that the temperature gradient within the egg was up to 4.7 degrees Celsius.
According to corresponding author CAS Professor Wei-Guo Du, any shift larger than 2 degrees Celsius can massively change the offspring sex ratio of many turtle species.
However, whether or not the embryo moves around due to temperature differences is dependent on some factors. "Embryonic thermoregulation can be limited if the thermal gradient within an egg is too small, or if the embryo is too large to move around or too young to have developed these abilities yet," added Du.
Would the ability of the turtle embryos be enough to counter the effects of climate changes, which has resulted in some sea turtle populations becoming nearly all-female?
Du is doubtful it can buffer the impact, but said that “the discovery of this surprising level of control in such a tiny organism suggests that in at least some cases, evolution has conferred an ability to deal with such challenges."