A research team in Germany has published new data on how pigeons use magnetic fields as a navigation method when visibility is limited. A key part of the long-sought answer could lie in an unexpected organ, their livers.

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But given the birds' inability to navigate magnetically without the assistance from their livers, the researchers concluded: "We propose that in homing pigeons, superparamagnetic macrophages in the liver are required for finding magnetic direction."

Macrophages are immune cells that break down old red blood cells. As part of this process, they accumulate iron, which may allow them to respond to magnetic fields.

Link to the paper