Too Many Girls? Warming Sands Threaten Mediterranean Sea Turtles

Rising temperatures across the Mediterranean are creating an unexpected problem for endangered sea turtles, with scientists warning that increasingly warm nesting beaches are producing far more female hatchlings than males.

Unlike humans, the sex of a loggerhead turtle (Caretta caretta) is determined by the temperature of the sand surrounding its eggs. Cooler nests generally produce males, while warmer conditions favour females.

As Mediterranean temperatures continue to rise, researchers are becoming increasingly concerned about the long-term consequences for turtle populations.

According to a recent Reuters report, research at Patara Beach in Turkey suggests that around 70% of loggerhead hatchlings are female. Elsewhere, scientists estimate that females may account for as many as 80–90% of hatchlings in some sea turtle populations.

Sea turtle biologist Yakup Kaska, who monitors nesting activity at Turkey’s Iztuzu Beach, reports that nest temperatures there have increased by almost 1°C over the past two decades.

Warmer conditions are also affecting nesting behaviour, with turtles laying their eggs earlier in the season and incubation periods becoming shorter.

And it’s not just the imbalance between males and females that concerns researchers. When nest temperatures climb above 30°C, the risk of embryos dying before hatching also increases.

Although producing more females might initially seem beneficial, scientists fear that continued warming could eventually leave too few males to maintain healthy breeding populations.

Despite these challenges, conservation efforts have helped protect important nesting beaches across the Mediterranean. At Iztuzu Beach, volunteers monitor nests throughout the night and protect eggs from predators, helping thousands of young turtles make their journey towards the sea.

The findings come ahead of the COP31 United Nations climate summit, which takes place in Antalya, Turkey, next month, where marine conservation is expected to feature among the discussions.

For a species that has survived for millions of years, the changing temperature of a few centimetres of sand could have profound consequences for future generations.

Source: Reuters, 16 October 2026 – Turtles offer early warning from a warming Mediterranean ahead of COP31

IMAGE: Young loggerhead turtle (Caretta caretta) swimming near the surface. Photo: Jane Morgan.