The Cape Verde Islands in the Atlantic are one of the places where many sea turtles come to lay eggs.

Research shows that 84 percent of the eggs hatched here are females.

Global warming is singled out as the cause.

The sex of all seven species is controlled by how hot it is during the egg's development phase. 


- In warm temperatures there are usually females and in lower more males, says conservation biologist Brendan Godley in the documentary "The last turtles?".

“Being cooked in the sand” 

Costa Rica, which also has a large population of sea turtles, shares the problem with too hot beaches.

The phenomenon 'arribada' takes place here regularly.

Up to half a million females then come to the same beach for a couple of days to lay and bury their eggs.

Here, researchers see how reduced precipitation has devastating consequences.  

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See why the island in West Africa is one of the places where males continue to hatch.

Photo: SVT / The documentary "The last turtles"

- The temperature reaches lethal levels and the eggs are boiled in the sand.

No chicks hatch at all from certain nests.

The rain is needed to lower the temperature in the sand, says marine biologist Vanessa Bezy. 

Scientists fear that climate change will lead to the extinction of certain populations of sea turtles.  


- We can reach a breaking point in some populations where very few or no males are born and the sand becomes too hot for hatching to succeed.

It will be doomsday for those populations, says Brendan Godley at the University of Exeter.

Can establish themselves in new places

At the same time, they see points of light.

With GPS tracking, it has been possible to see that males move over large areas and could fertilize females in populations where the males are too few.

There is also a possibility that climate change will cause the sea turtle to establish itself in new places.



- There are places where they can reproduce where they currently do not live, says researcher Brendan Godley.

Want to know more about how climate change threatens the sea turtle.

Watch the entire documentary "The last turtles?"

in SVT Play or on Tuesday 10 August at 20:00 in SVT2.