Gender Gap: Sea Turtles Skew Female

Scientists warn that as the Earth gets hotter, sea turtle hatchlings worldwide are expected to trend dangerously female. The West African island of Cape Verde is home to a sixth of the planet’s total nesting loggerheads, and 84 percent of youngsters are now female, researchers from Britain’s University of Exeter stated in a July report. “Males here could vanish in two or three decades,” says Adolfo Marco, a Spanish researcher. “There will be no reproduction.”

Sea turtle eggs that incubate in sand below 81.86 degrees Fahrenheit produce males, according to the National Oceanic and Atmospheric Administration, while nests in the mid-80s create a gender mix. Temperatures higher than 87.8 degrees effect 100 percent females. In Cape Verde, the sand temperature has risen about 2.3 degrees Fahrenheit since 1964. Populations in Florida and Australia are also showing dramatic sex imbalances, casting the shadow of extinction over the ancient species. Sea turtles can live for 100 years and lay more than 1,000 eggs. They are polyamorous, and one male can fertilize dozens of females.

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