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How Does Climate Change Impact Turtle Sex Ratios?

By 29 August 2023November 3rd, 2023No Comments

Sea turtles make their nests in the sand. Most turtles even return to the beach where they were born. However, most eggs do not hatch because they fall prey to microbes, wild animals or other turtles that destroy new nests.

Once they have hatched, the turtles must return to the ocean as quickly as possible, avoiding predators such as seabirds and raccoons.

Once in the ocean, other predators such as crabs and fish still threaten the baby turtles. As a result, only 1% of baby turtles reach adulthood.

Turtles heading for the ocean

The gender ratio issue

For turtles, the gender of the baby turtles is defined by the temperature of the nest: below 27.7 degrees Celsius, the turtles laid will be males and above 31 degrees Celsius, the baby turtles will be females.

Now, with climate change, the temperature of the sand is getting warmer, resulting in more female baby turtles being born than male baby turtles.

“All over the world, the sea turtle gender balance is being thrown way out of whack” (Lucy Hawkes, an English ecologist who led a study on Boa Vista)

This is what researcher Camryn Allen, a scientist with the National Oceanic and Atmospheric Administration in Hawaii, found when she studied Pacific Ocean green turtles in their largest nesting area, on Raine Island in Australia.

In fact, as the sand warmed up, baby turtles now outnumbered baby male turtles 116 to one.

The same was true in San Diego, where the number of baby female green turtles rose from 65% to 78% as the sands got hotter and hotter.

Hatching turtles

“There will be no reproduction. Males here could vanish in two or three decades” (Adolfo Marco, a Spanish researcher)

And if the male turtles were to disappear, the whole species would disappear…


Solutions and initiatives

To tackle this imbalance, initiatives such as the Nest Dome manufactured by Wunderman Thompson for Banana Boat and The Colombian Sea Turtle Conservation Program are being launched.

The domes, inspired by the shape of turtle shells, are made from natural materials and help to protect and cool the nests they cover, thanks also to slits that circulate the air.

Source: Wunderman Thompson