Pigeons Use 12.4-Mile Liver Compass as Iron-Rich Immune Cells Sense Earth’s Magnetic Field
Updated
Updated · Popular Science · May 28
Pigeons Use 12.4-Mile Liver Compass as Iron-Rich Immune Cells Sense Earth’s Magnetic Field
17 articles · Updated · Popular Science · May 28
Science published evidence that pigeon liver macrophages act as an internal compass, using iron nanoparticles to detect Earth’s magnetic field.
Iron from broken-down red blood cells makes those immune cells superparamagnetic; the particles align in a magnetic field and appear to pass signals to the brain through nearby nerve fibers.
In tests with pigeons trained to return to an aviary from more than 12.4 miles away, birds whose macrophages were removed got lost under overcast skies but still homed successfully in sunshine.
The result helps explain how birds combine magnetic and solar cues, and researchers say the mechanism could also apply to night migrants and animals such as sharks or bats navigating in darkness.
The finding also broadens “immuno-sensation,” suggesting the immune system can detect environmental signals beyond pathogens and tissue damage.
Is the pigeon's liver its only internal compass, or part of a larger navigation system?
Could this liver-based 'sixth sense' exist in other animals, or even in humans?