Researchers have identified what may be the oldest known animal navigation system: 97-million-year-old magnetofossils preserved in ancient seafloor sediments. The tiny structures, shaped like spearheads, spindles, bullets, and needles, are no larger than bacterial cells and were likely produced by an unknown ocean organism.
Using a new 3D magnetic imaging technique, scientists from the University of Cambridge and Helmholtz Zentrum Berlin mapped the internal magnetic structure of the fossils. They found a tornado-like vortex pattern that appears optimized for detecting both the direction and strength of Earth's magnetic field. According to the researchers, this would have allowed the creature to determine its latitude and longitude-like information, enabling navigation across thousands of kilometers.
The findings, published in Communications Earth & Environment, provide the first direct evidence that animals used magnetoreception at least 97 million years ago. Modern bacteria use simpler magnetic particles as compass needles, but these giant magnetofossils are 10 to 20 times larger and show far more complex magnetic behavior. The discovery helps explain how this poorly understood sense may have evolved in birds, fish, and insects.