What is the story about?
NEW YORK (AP) — A surprising gut feeling may help pigeons find their way home. Animals use various techniques to navigate, including following the stars
and remembering key landmarks. Birds, fish, and turtles orient themselves using Earth's magnetic field as a compass, but the exact mechanisms remain unclear.
Pigeons, known for their remarkable ability to travel long distances, can cover hundreds of miles in a single day. For centuries, humans have relied on them to carry messages and news.Researchers have long sought to understand how these birds navigate without losing their way. Some scientists propose that pigeons detect magnetic cues through light-sensitive molecules in their eyes, while others suggest that the mechanism may be located in the beak or inner ear.
Martin Wikelski, a researcher at the Max Planck Institute of Animal Behavior in Germany, stated, “The magnetic sense has been this mystery for almost 100 years.” In a recent study, Wikelski and colleagues investigated the navigational abilities of pigeons and discovered a strong magnetic signal emanating from an unexpected organ: the liver.
In their findings, they noted that specialized immune cells within the pigeon's liver break down red blood cells and store iron. When the researchers temporarily removed these immune cells and allowed the pigeons to fly, the birds “just couldn't find their way,” according to Christian Kurts from the University of Bonn in Germany. This observation suggests that the iron-rich liver cells may be integral to the birds' navigational capabilities.
The study revealed that the pigeons' magnetic compasses were particularly affected on overcast days, as they also rely on the sun for navigation. While the role of immune cells in magnetic sensing had been previously speculated, this study, published in the journal Science, is the first to propose a comprehensive theory on the matter.
Albert Kao, a behavioral ecologist from the University of Massachusetts Boston who was not involved in the study, remarked, “I would never have guessed it, but once it was explained to me, it makes sense.” The immune cells are situated near nerve fibers in the liver, which may facilitate their transmission of magnetic signals to the brain, aiding the pigeons in navigation, as explained by study co-author Clivia Lisowski from the University of Bonn.
The researchers hypothesize that other birds and animals, including mice, may also utilize a similar magnetic navigation system. However, experts outside the study caution that further research is needed to confirm that pigeons navigate using this mechanism and to clarify how these signals are processed by the brain. They noted that while the strongest magnetic signal was detected in the pigeons' livers, similar immune cells have also been found in other parts of the body, including the beak and spleen.
Veterinary pathologist Simon Spiro and biologist Hal Drakesmith commented in an accompanying editorial that the magnetic navigation puzzle might not have a single solution. They suggested that birds could employ different methods to sense magnetic fields depending on the circumstances, such as traveling long distances or pinpointing a specific location. “Indeed, it could be prudent to have more than one way of getting home in the dark,” they wrote.
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.
