Scientists have made a surprising discovery regarding how pigeons navigate. Throughout history, pigeons have been relied upon to deliver important messages over long distances. Researchers have long known that pigeons use various cues like the sun, smells, and visual landmarks to navigate. However, when these cues are absent, such as during overcast skies or nighttime flights, pigeons also appear to rely on the Earth’s magnetic field. Despite this knowledge, scientists have been puzzled about how pigeons precisely utilize this magnetic sense.
Recent research led by Clivia Lisowski and her team suggests that iron-rich immune cells in pigeons’ livers may be serving as sensors that detect the Earth’s magnetic field to aid in navigation. This breakthrough idea emerged from previous studies in mice, where it was found that immune cells in the spleen, accumulating iron from old red blood cells, were sensitive to magnetic fields. Collaborating with animal behavior scientist Martin Wikelski, the researchers found that pigeon livers contain a high concentration of iron-rich macrophages, which play a role in recycling and iron extraction.
To test their hypothesis, the team temporarily disrupted macrophages in pigeons and observed that untreated pigeons could orient themselves, while those without functioning macrophages struggled to navigate. This finding has been lauded by experts like David Bird, an emeritus professor, who believes this discovery could shed light on how other animals, including migratory birds like pigeons, sharks, and dogs, navigate. Scott MacDougall-Shackleton, director of avian research at Western University, also expressed intrigue at the research, suggesting that it could broaden our understanding of how organisms interact with their environment.
While this research opens up new possibilities for understanding animal navigation, further studies are needed to validate the mechanism and eliminate alternative explanations. Researchers are particularly interested in exploring how magnetic information is transmitted from the liver to the brain and utilized by pigeons for direction. Clivia Lisowski emphasizes that this research has transformed her perspective on the immune system, highlighting the immune system’s potential as a sensory organ beyond its traditional role in defense.