Many animals use a natural magnetic mineral called magnetite as an internal compass for navigation.

Magnetite (Fe3O4) is the most magnetic naturally occurring mineral on Earth. For decades, biologists have studied how organisms use this mineral for magnetoreception, which is the ability to perceive magnetic fields. In 1975, Richard Blakemore discovered magnetotactic bacteria that use internal magnetite chains to align themselves with Earth's magnetic lines. This discovery proved that biological systems could synthesize and utilize magnetic minerals for orientation.In birds, specifically homing pigeons, researchers have identified magnetite clusters within the upper beak and inner ear. A study published in the journal 'Nature' highlighted that these deposits are linked to the trigeminal nerve, which sends magnetic data directly to the brain. This allows the birds to determine their geographic position by sensing the intensity and inclination of the magnetic field. It is estimated that these biological compasses are sensitive enough to detect changes as small as 10 to 100 nanoteslas.Honeybees also utilize magnetite, with particles found in their abdominal cells. Research conducted at the University of Hawaii demonstrated that bees use these sensors to navigate between food sources and their hives. Even some aquatic species, like sockeye salmon and sea turtles, rely on magnetite for long-distance migrations across featureless oceans. This internal navigation system is so precise that it functions effectively even in total darkness or under heavy cloud cover.