Nearly all sea turtles born in Florida are now female due to climate crisis

In 2019, one South Florida scientist had documented only female hatchlings in seven of the preceding 10 years

As Climate Change Worsens These Sea Turtles Are Finding It Difficult to Cope

When sea turtles lay their eggs, the temperature of the sand determines whether that egg becomes a male or female turtle.

But the planet is getting hotter— and that means a lot more turtles, in key nesting sites like Florida, are being born female.

"Scientists that are studying sea turtle hatchlings and eggs have found no boy sea turtles, so only female sea turtles for the past four years," Bette Zirkelbach, who manages a turtle rescue operation in the Florida Keys, told Reuters.

Sea turtles live in the ocean but come up onto beaches all over the world to lay their eggs in the sand.

When the sand is cooler, more of those eggs become males — and when it’s warmer, more of the eggs become females.

The precise temperature at which the change occurs may differ between species and locations, but at around 29 degrees Celsius (84 degrees Fahrenheit) you’ll often see a 50/50 split between male and female hatchlings.

However the climate crisis is pushing temperatures up around the world, and the oceans are filling up with female turtles.

In 2019, the Miami Herald reported that one South Florida scientist had documented only female hatchlings in seven of the preceding 10 years.

These kinds of results are showing up elsewhere, too. A 2018 paper found that while cooler beaches in Australia’s Great Barrier Reef had between 65-69 per cent female turtles, warmer beaches in the reef had upwards of 90 per cent female turtles.

In Cape Verde, an island nation off West Africa, beaches with light-coloured sand produced around 70 per cent female turtles, while beaches with dark-coloured sand produced around 93 per cent female turtles, according to a 2014 study. Dark colours absorb more energy from the sun, making them hotter.

This process is called “feminization” — and some scientists warn that it could be a long-term threat to sea turtles as the climate crisis pushes temperatures even higher, as both males and females are needed for the species to reproduce.

The same issue may also threaten other reptiles whose eggs’ sex is based on temperature, like alligators.

There are some potential mitigations for this problem, such as providing more shade on beaches, covering nests in lighter-coloured sand or moving nests to cooler spots.

But all of these require human interference with the nesting process, which the sea turtles have been doing undisturbed for millions of years.

In addition to higher temperatures, sea turtles face other climate-related threats like sea-level rise and intense hurricanes, which can damage their coastal nesting sites.

Register for free to continue reading

Registration is a free and easy way to support our truly independent journalism

By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists

Please enter a valid email
Please enter a valid email
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Please enter your first name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
Please enter your last name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
You must be over 18 years old to register
You must be over 18 years old to register
Opt-out-policy
You can opt-out at any time by signing in to your account to manage your preferences. Each email has a link to unsubscribe.

By clicking ‘Create my account’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Already have an account? sign in

By clicking ‘Register’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Register for free to continue reading

Registration is a free and easy way to support our truly independent journalism

By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists

Already have an account? sign in

By clicking ‘Register’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Join our new commenting forum

Join thought-provoking conversations, follow other Independent readers and see their replies

Comments

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged inPlease refresh your browser to be logged in