For decades, scientists have known that many animals—from birds to sea turtles—possess an internal “biological GPS” using Earth’s magnetic field for navigation. However, the exact mechanisms and evolutionary origins of this magnetoreception remained largely mysterious. Now, a new study by researchers at Cambridge University and the Helmholtz-Zentrum Berlin provides the first direct evidence that animals have been navigating using this method for at least 97 million years.
The Discovery of “Giant” Magnetofossils
The breakthrough stems from analyzing microscopic fossils—dubbed “giant” magnetofossils due to their unusually large size compared to magnetic receptors found in bacteria—scattered across ancient ocean floors. These fossils contain internal structures that clearly indicate the ability to sense and interact with magnetic fields.
Previously, studying the inner workings of such fossils was difficult because traditional X-ray techniques couldn’t penetrate their outer layers. Researchers overcame this hurdle by developing a new method called magnetic tomography, which uses magnetic fields to visualize internal structures. This technique allowed them to map the arrangement of tiny magnetic fields within the fossils, confirming their magnetoreceptive capabilities.
“Whatever creature made these magnetofossils, we now know it was most likely capable of accurate navigation,” explains Rich Harrison, co-leader of the research team at Cambridge’s Earth Sciences Department.
A Missing Link in Evolutionary History
The significance of this discovery lies in its ability to bridge a gap in understanding how simple bacterial magnetoreception evolved into sophisticated, GPS-like navigation systems in more complex animals. The fossils suggest that the underlying mechanisms for sensing magnetic fields have been around for a very long time.
The exact animal that created these fossils remains unknown, though eels—which evolved around 100 million years ago and are known for their long-distance migrations—are a leading candidate. Identifying the creature is now a key focus for future research.
Implications for Understanding Animal Behavior
This study isn’t just about ancient history; it has implications for understanding modern animal behavior. If scientists can pinpoint the creature responsible for these fossils, it could unlock further insights into how magnetic navigation works in living species. The findings also highlight the power of interdisciplinary research, combining paleontology, geophysics, and advanced imaging techniques to solve long-standing biological mysteries.
The discovery of these ancient magnetofossils confirms that magnetic navigation isn’t a recent evolutionary development, but rather a deeply rooted ability that has shaped animal life on Earth for millions of years.
