Why 99% sea turtles in Florida are born female?

Florida sea turtles face a gender imbalance exacerbated by climate change. Recent heat waves have made the sand on some beaches so hot that nearly all of the turtles hatched were female. 

"The scariest thing is that the last four summers in Florida have been the hottest on record," says Bette Zirkelbach, director of the Turtle Hospital in Marathon, a city in the Florida Keys, a chain of tropical islands. stretching from the southern tip of the state. 

"Scientists studying sea turtle hatchlings and eggs haven't found any males, so there are only female sea turtles in the last four years," said Zirkelbach, whose turtle center has been in business since 1986.  

When a female turtle digs a nest on a beach, the temperature of the sand determines the sex of the hatchlings. Zirkelbach said an Australian study showed similar statistics: "99% of new sea turtle hatchlings are female."  

Rather than determining sex during fertilization, the sex of sea turtles and alligators depends on the temperature of the developing eggs, according to the National Oceanographic and Atmospheric Administration (NOAA). 

If a turtle's eggs are incubated below 80 degrees Fahrenheit (27.7 degrees Celsius), the hatchlings will be male, while if they are incubated above 90 degrees Fahrenheit, they will be female, according to the National Health Service website.

"Over the years, there's going to be a sharp population decline because we don't have genetic diversity," says Melissa Rosales Rodriguez, a sea turtle keeper at Zoo Miami's newly opened turtle hospital. "We don't have the male to female ratio needed to be able to have successful breeding sessions." 

“The scary thing is that the last four summers in Florida have been the hottest summers on record,” said Bette Zirkelbach, manager of Turtle Hospital in Marathon, a city in the Florida Keys, which is a chain of tropical islands that stretches from the southern end of the state.

"Scientists studying sea turtle hatchlings and eggs have found not male sea turtles, but female sea turtles for the past four years," said Zirkelbach, whose turtle center has operated since 1986.

The trend is just one of many signs that the climate crisis is interfering with Earth's natural ecosystems, moving too fast for many species to adapt.

When a female turtle digs a nest on a beach, the temperature of the sand determines the sex of the hatchlings. Zirkelbach said an Australian study showed similar statistics: "99% of new baby sea turtles are female."

Rather than determining sex during fertilization, the sex of sea turtles and alligators depends on the temperature of the developing eggs, according to the National Oceanographic Atmospheric Administration (NOAA).

If a turtle's eggs are incubated below 81.86 Fahrenheit (27.7 Celsius), the turtle hatchlings will be male, while if they are incubated above 88.8 F (31C), they will be female, according to the NOAA's National Ocean Service website.

"Over the years, you're going to see a sharp decline in their population because we just don't have the genetic diversity," said Melissa Rosales Rodriguez, a sea turtle keeper at the recently opened turtle hospital at Zoo Miami. "We don't have the male-to-female ratio necessary to be able to have successful breeding sessions.

"The two turtle hospitals are also fighting tumors in turtles known as fibropapillomatosis, also known as FP. These tumors are contagious to other turtles and can cause death if left untreated.

With the weather affecting the tortoises' future and the disease so widespread, Zirkelbach sees a need to save as many tortoises as he can and open more rehabilitation centers.

“Turtle Hospital was the first. But unfortunately and fortunately, there is a need throughout Florida.”

Keep Reading

Part 1: Cloudburst  in Ganderbal's Padabal village & unfulfilled promises