Environmental Intelligence, Natural GPS

A new study confirms that the loggerhead sea turtle Caretta caretta has an amazing ability to learn and memorize the coordinates of the Earth's magnetic field, using them as a veritable natural GPS to navigate to their favorite nesting and feeding sites. The discovery, published in the prestigious journal Nature, provides the first direct evidence that these animals can learn and recognize specific magnetic fingerprints, strengthening the hypothesis of a dual orientation mechanism.

• A natural navigation system based on the magnetic field

Caretta caretta turtles are large migrants, able to cross the oceans guided by currents and an internal orientation system. They use the Earth's magnetic field not only to maintain their direction, but also to recognize familiar locations based on the strength and inclination of the magnetic field lines. To demonstrate this ability, researchers at the University of North Carolina conducted experiments with young captive turtles, exposing them to magnetic conditions similar to those in the Atlantic Ocean. For two months, they were fed only in a specific artificial magnetic zone. The result was surprising: even in the absence of food, the turtles recognized the correct location, demonstrating that they can remember and use these magnetic landmarks to navigate.

• Electromagnetic interference can disrupt turtle orientation

Another experiment tested the effect of radio waves on turtle orientation. When exposed to a radio frequency emission, the turtles lost their direction, scattering randomly, suggesting that their navigation is sensitive to electromagnetic disturbances.

• Implications for the conservation of migratory species

These findings not only reveal a fascinating mechanism for orientation in turtles, but may also have important implications for their conservation. Since electromagnetic interference can affect their ability to navigate, electromagnetic pollution generated by human activities could pose a significant risk to the migration and survival of these animals. This research opens new insights into how migratory animals plan their routes and suggests that similar mechanisms may be found in other species, such as birds and salmon.