Study links pigeon liver macrophages to magnetic navigation

Scientists have identified a potential new biological mechanism that may explain how homing pigeons navigate across long distances, according to a new study. The research suggests specialized immune cells in the birds' livers, rich in iron, could act as an internal compass by detecting Earth's magnetic field.

The study, published in the journal Science, points to macrophages in the liver as key suspects. These cells, part of the immune system, break down old red blood cells and accumulate iron in the form of tiny iron-oxide nanoparticles. An international team, including researchers from the University of Bonn, University Hospital Bonn, the University of Duisburg-Essen, and the Max Planck Institute of Animal Behavior, found these cells exhibit superparamagnetic properties, making them highly responsive to magnetic fields.

"We didn't expect immune cells to act like sensors for magnetic fields at all," said Christian Kurts, director of the Institute of Molecular Medicine and Experimental Immunology at University Hospital Bonn and a co-senior author of the study. "Our results reveal a previously unknown mechanism for magnetic perception in animals."