Because incubation temperature of turtle eggs determines the animalís sex, a warmer nest results in more females. Increasing temperatures in Queenslandís north, linked to climate change, have led to virtually no male northern green sea turtles being born.

For the study, scientists caught green turtles at the Howick Group of islands where both northern and southern green turtle populations forage in the Great Barrier Reef. Using a combination of endocrinology and genetic tests, researchers identified the turtlesí sex and nesting origin.