All the Sea Turtles Are She Turtles
Climate change has done a number on the sex ratio.
Florida’s green sea turtles are making a comeback — sort of.
They had their best-ever nesting season in 2023, with 74,300 nests — a 40% increase over the previous record, set in 2017, The New York Timesreports. But this welcome news comes with an unsettling catch: The percentage of male turtle hatchlings has dropped precipitously. In recent seasons, according to the Times, “Between 87 and 100 percent of the hatchlings” tested by Dr. Jeanette Wyneken, a professor at Florida Atlantic University, were female.
Climate change is a likely contributor to the imbalance, as a green sea turtle’s sex is determined by the temperature of the sand in which its egg develops. Warmer sand results in more females; cooler sand, more males. In the short term, this might benefit the turtles, with more females able to produce more eggs once they reach maturity (providing “there’s enough boys to service the girls,” as Dr. Wyneken put it). But another side effect of the changing climate is that extreme heat dries out the turtles’ nests — killing the baby turtles before they’ve had a chance to hatch.
As with so much else in the natural world, such news is a case of two steps forward, one step back (or, perhaps, one flipper-crawl back). Thanks in part to decades of conservation efforts, 2023 has also seen record green sea turtle nest counts in Texas and Alabama — and while such milestones are a cause to celebrate, climate change’s effects on the resulting offspring are a reminder that there is always more work to do.