Hotter climate could turn sea turtles all-girl

It has been known for decades that reptile reproduction is highly sensitive to temperature, with the ratio of male to female offspring varying. For species of sea-turtles, the pivotal temperature is an oddly uniform 29 degrees for incubation, beyond which more females emerge from the eggs

At about 30.5 degrees, populations become fully female. As remaining males die off, ''it will be end of story without human intervention'', Professor Hays said. At higher than 33 degrees, embryos do not survive.

The study focused on a globally important loggerhead turtle rookery on the Cape Verde Islands in the Atlantic but its results also apply to species elsewhere, including the Pacific. It found light-coloured sandy beaches already produce 70.1 per cent females, while beaches with darker sands are at 93.5 per cent.

The findings should help steer conservation efforts to make a priority of protecting lighter-coloured sandy beaches or planting more vegetation near dark ones to ameliorate the warming. 

It remains to be seen whether sea turtles, which have survived hundreds of millions of years, can adjust quickly enough to a changing climate.

Possible adjustments could include females laying their eggs at milder times of the year or shifting to cooler regions.

Read more: http://www.smh.com.au/environment/animals/hotter-climate-could-turn-sea-turtles-allgirl-20140518-38hy2.html#ixzz32B0jfzDF