When the Going Gets Hot, The Sea Turtles Go All-Female

From the Sydney Morning Herald:

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.

This is pegged to a new study on temperature-dependent sex determination and other aspects of Turtle Warming, published online today:

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 abstract says that “entire feminization of this population is not imminent,” but my mind is already in a very Margaret Atwood place about all of this. [SMH]