magnetic fields? Migratory sea turtles actually have no idea where they swim – Wel.nl

Earth’s magnetic fields guide birds as they migrate south. It has long been thought that this also applies to sea turtles, but this is disappointing: their sense of direction leaves much to be desired.

How migratory animals, such as sea turtles, travel hundreds or even thousands of miles across the ocean has intrigued scientists since Charles Darwin. But now it turns out that they may not have such a clear idea of ​​where to swim.

An international group of scientists has tracked the movements of 22 hawksbill turtles as they migrate from where they lay eggs to where they forage. Find out, as they write in Royal Society Interface Magazine, that animals take a big turn. They traveled twice the distance required to reach their destination. One swam 1,306 kilometers to land on an island only 176 kilometers away.

in a straight line
So the researchers conclude that their open ocean navigation skills are somewhat disappointing. Animals only know approximately where to swim. “The sea turtles we tracked had not eaten for four to five months,” said study leader Professor Graeme Hayes of Deakin University. against the Guardian† If they knew exactly where to go, they most likely swam in a straight line to their destination.

Previous research appears to indicate that sea turtles, like birds, only use Earth’s magnetic fields for migration. “In fact, they’re almost certainly using geomagnetic navigation, but it’s partly and globally guiding them in the right direction,” Hayes says.

According to the scientist, animals also have other ways. This way they can smell the island they want to go to and may just get to know the place. “They see the sandbar because the water gets less deep, just as we learn about things when we get into a familiar environment.”