The government and environment groups in Japan have been surveying temperatures of nesting sites for endangered loggerhead sea turtles as warmer incubation periods brought on by climate change risks creating an outsize proportion of female hatchlings.
The sex of a sea turtle is determined by the temperature at which the egg is incubated. Higher temperatures produce more females, and cases of groups of hatchlings being almost entirely female have been reported overseas.
Experts warn that if temperatures continue to rise, loggerhead sea turtles born in Japan are also at risk of being mostly female, putting the species under the threat of extinction.