Climate change is creating more female sea turtles than males - and it could end the species

The animal's temperature-dependant reproductive process could be good news in the next decades but lead to extinction in the long term

Temperature rises triggered by climate change could kill off the world’s population of sea turtles as hotter sands – where the creatures bury their eggs – cause more females than males to be born.

This is because the gender of sea turtle offspring is not decided by sex chromosomes, but by the ambient temperature of the beaches where mothers bury their eggs.

“The logic is that warming temperatures will lead to more female hatchlings being produced, because the females are produced at the warmer temperatures,” Professor Graeme Hays, one of the lead authors of the new study published in the journal Nature Climate Change, told The Guardian.

At what Hays calls the “pivotal temperature” of 29C the ratio of male to female sea turtles is balanced, but an increase of just two degrees could “almost exclusively produce female hatchlings”.

The same study also found a strong correlation between the colour of a beach and the gender ratio of hatchlings, with light-coloured sandy beaches reflecting more heat and so producing less female sea turtles. Darker beaches absorbed more heat and produced more females – as many as 93 per cent in some cases.

Sea turtle mothers lay their eggs in the sand, with the offspring crawling to the saftey of the ocean around 60 days later.

In the short term these changes might actually be beneficial to sea turtles, as males breed more often than females meaning that over the next two to three decades there will actually be a “population expansions” as more females lay more eggs.

However, Professor Hays warned that this ­pattern was far from sustainable. “Ultimately, if you extrapolate long enough into the future […] once you get 100 years or more into the future, then things start to look serious. You have so few males left that it’s likely to be a problem. There will be heaps of female but not enough males to fertilise all those eggs.”

The study suggested that while sea turtle populations might migrate to cooler parts of the world as a result, humans could also help by moving nests from dark beaches to light beaches or planting vegetation as shade on beaches with hotter temperatures.

However, these temperature changes are likely to affect other animals as well. Crocodiles, alligators and several species of lizard also have temperature-dependant gender, although for each animal the precise “pivotal temperature” differs.

Scientists are still uncertain why this particular reproductive quirk evolved, though some speculate that temperature-dependant gender allowed sex to best match the baby’s environment, while others suggest that it gave mothers some choice over the gender of their offspring.  

Start your day with The Independent, sign up for daily news emails
Property
pets
Arts and Entertainment
The Ridiculous Six has been produced by Adam Sandler, who also stars in it
filmNew controversy after nine Native American actors walked off set
Life and Style
The original ZX Spectrum was simple to plug into your TV and get playing on
techThirty years on, the ZX Spectrum is back, after a fashion
Sport
football
ebooks
ebooksA celebration of British elections
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Senior Digital Marketing Consultant

£28000 - £45000 per annum: Recruitment Genius: A Senior Digital Marketing Cons...

Recruitment Genius: Assistant Stores Keeper

£16640 - £18500 per annum: Recruitment Genius: An Assistant Stores Keeper is r...

Recruitment Genius: Claims Administrator

£16000 - £18500 per annum: Recruitment Genius: This is an excellent opportunit...

Recruitment Genius: Software Developer - C# / ASP.NET / SQL

£17000 - £30000 per annum: Recruitment Genius: Developer required to join a bu...

Day In a Page

'It was first time I had ever tasted chocolate. I kept a piece, and when Amsterdam was liberated, I gave it to the first Allied soldier I saw'

Bread from heaven

Dutch survivors thank RAF for World War II drop that saved millions
Britain will be 'run for the wealthy and powerful' if Tories retain power - Labour

How 'the Axe' helped Labour

UK will be 'run for the wealthy and powerful' if Tories retain power
Rare and exclusive video shows the horrific price paid by activists for challenging the rule of jihadist extremists in Syria

The price to be paid for challenging the rule of extremists

A revolution now 'consuming its own children'
Welcome to the world of Megagames

Welcome to the world of Megagames

300 players take part in Watch the Skies! board game in London
'Nymphomaniac' actress reveals what it was really like to star in one of the most explicit films ever

Charlotte Gainsbourg on 'Nymphomaniac'

Starring in one of the most explicit films ever
Robert Fisk in Abu Dhabi: The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers

Robert Fisk in Abu Dhabi

The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers
Vince Cable interview: Charging fees for employment tribunals was 'a very bad move'

Vince Cable exclusive interview

Charging fees for employment tribunals was 'a very bad move'
Iwan Rheon interview: Game of Thrones star returns to his Welsh roots to record debut album

Iwan Rheon is returning to his Welsh roots

Rheon is best known for his role as the Bastard of Bolton. It's gruelling playing a sadistic torturer, he tells Craig McLean, but it hasn't stopped him recording an album of Welsh psychedelia
Russell Brand's interview with Ed Miliband has got everyone talking about The Trews

Everyone is talking about The Trews

Russell Brand's 'true news' videos attract millions of viewers. But today's 'Milibrand' interview introduced his resolutely amateurish style to a whole new crowd
Morne Hardenberg interview: Cameraman for BBC's upcoming show Shark on filming the ocean's most dangerous predator

It's time for my close-up

Meet the man who films great whites for a living
Increasing numbers of homeless people in America keep their mobile phones on the streets

Homeless people keep mobile phones

A homeless person with a smartphone is a common sight in the US. And that's creating a network where the 'hobo' community can share information - and fight stigma - like never before
'Queer saint' Peter Watson left his mark on British culture by bankrolling artworld giants

'Queer saint' who bankrolled artworld giants

British culture owes a huge debt to Peter Watson, says Michael Prodger
Pushkin Prizes: Unusual exchange programme aims to bring countries together through culture

Pushkin Prizes brings countries together

Ten Scottish schoolchildren and their Russian peers attended a creative writing workshop in the Highlands this week
14 best kids' hoodies

14 best kids' hoodies

Don't get caught out by that wind on the beach. Zip them up in a lightweight top to see them through summer to autumn
Robert Fisk in Abu Dhabi: The acceptable face of the Emirates

The acceptable face of the Emirates

Has Abu Dhabi found a way to blend petrodollars with principles, asks Robert Fisk