Climate change killing nestlings with heat could be worse than sex ratios going too female
Worries about climate change threatening sea turtles may have been misdirected.
Warming that could lead to far more female hatchlings than males isn’t the most immediate danger from climate shifts. Lethally overheated beach nests are more important, researchers argue February 8 in Proceedings of the Royal Society B.
Climate change can meddle with sex ratios of the seven species of sea turtles because their embryos start life without a genetically fixed sex. Nest temperatures greater than roughly 29° Celsius tip the ratio toward more female hatchlings, explains marine ecologist Graeme Hays of Deakin University in Warrnambool, Australia.
Warm the nesting beaches enough, and sea turtle populations with few to no male mates might get feminized to extinction, biologists have warned. Yet records from 75 sea turtle nesting sites around the world suggest that many still-abundant populations are skewed to extreme female bias. “That’s not