97-million-year-old fossils reveal earliest known animal magnetic navigation

October 2, 2026 at 05:28 PM2 min

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Researchers have identified 97-million-year-old magnetic fossils that may be the earliest evidence of an internal animal navigation system. The fossils, preserved in ancient seafloor sediments, show structures optimized for detecting Earth's magnetic field direction and strength. The findings, reported in Communications Earth & Environment, suggest animals were navigating using magnetoreception at least 97 million years ago.

Key Facts

The magnetic fossils date back 97 million years and were preserved in ancient seafloor sediments.
The fossils come in shapes resembling spearheads, spindles, bullets, and needles, each no larger than a bacterial cell.
Scientists from the University of Cambridge and Helmholtz Zentrum Berlin produced the first 3D images of the magnetic structure inside the fossils.
The findings are reported in the journal Communications Earth & Environment.
Some bacteria living in lakes use chains of magnetic particles 50-100 nanometers wide to orient with Earth's magnetic field.

Magnetic Navigation Evidence

The fossils, known as magnetofossils, appear to have been produced by an organism whose identity remains unknown. The 3D analysis revealed features optimized for detecting both the direction and strength of Earth's magnetic field. Professor Rich Harrison from Cambridge's Department of Earth Sciences said the creature was most likely capable of accurate navigation. The findings provide the first direct evidence that animals were navigating with Earth's magnetic field at least 97 million years ago.

Magnetoreception and Bacterial Compasses

Magnetoreception remains one of the least understood senses found in nature, with birds, fish, and insects using Earth's magnetic field to travel enormous distances. One leading idea involves magnetite, a magnetic mineral that may form tiny crystals inside an animal's body, aligning with Earth's magnetic field like microscopic compass needles. Some bacteria living in lakes and other aquatic environments use chains of magnetic particles to orient themselves with Earth's magnetic field. Harrison noted that at just 50-100 nanometers wide, these particles are the perfect compass needles, and smaller is better for an efficient magnetic sense. The magnetofossils examined in the new research are much larger than these bacterial particles.