A Hidden Liver Compass May Help Pigeons Navigate Long Distances
Indian Express
Homing pigeons have long fascinated scientists with their ability to find their way back over long distances. But exactly how they do it has remained one of nature s biggest mysteries
Homing pigeons have long fascinated scientists with their ability to find their way back over long distances. But exactly how they do it has remained one of nature’s biggest mysteries. However, a new study published in the journal Science suggests the birds may rely on an unexpected navigation tool: iron-rich immune cells in their liver.
Many animals, including birds, sea turtles, sharks and dogs, are believed to use Earth’s magnetic field to navigate. Scientists have proposed various explanations over the years, from magnetic particles acting like tiny compass needles to special proteins in the eyes helping animals detect magnetic fields.
The new study points to a surprising alternative. Researchers found that immune cells called macrophages in the livers of homing pigeons contain large amounts of iron stored in a protein called ferritin. These cells were located close to nerve cells, suggesting they may help detect magnetic information and pass it on to the brain.
To test the idea, scientists trained 34 homing pigeons to fly a 19-kilometre route. They then used a drug to temporarily remove these iron-rich immune cells in some of the birds.
However, when the same treated pigeons were released on sunny days, they navigated successfully using the Sun as a guide. This suggests the liver cells may specifically help pigeons sense Earth’s magnetic field when other navigation cues are unavailable.
Scientists are still trying to understand exactly how the process works. One possibility is that the iron stored inside the cells responds to Earth’s magnetic field and sends signals to nearby nerves, which then relay the information to the brain.
Experts who were not involved in the research have called the findings “mind-blowing” and “extraordinarily exciting,” though they caution that more studies are needed.
If confirmed, the discovery could have implications far beyond pigeons. Researchers believe similar mechanisms may exist in other animals that rely on magnetic navigation, from bees and bats to whales and sharks.