It’s well-known that birds have a great sense of orientation that helps them migrate and then find their way back home. It turns out they might be able to see magnetic fields and follow them during their migration routes. This is possible thanks to some special proteins these birds have in their eyes.
Birds can sense Earth’s magnetic fields and orient
Scientists have come up with dozens of theories to explain birds’ unusual sense of orientation. At first, they assumed they had some cells rich in iron in their beaks, and this helped them find their way. However, a new research proves this theory wrong, suggesting the secret lies in birds’ eyes.
Scientists concentrated on a unique molecule they called Cry4, or cryptochromes. This protein is present in the retina, is sensitive to light and, according to the studies, it evolved with the clear purpose to identify magnetic fields. Also, this protein is strictly of animal origin, so it’s impossible to find it in humans.
Cry4 proteins function over a 24-hour cycle
Cry4 proteins play an important role in regulating the circadian rhythm of the body. However, scientists have just discovered that some of these proteins can read magnetic fields. Therefore, it is really possible that birds should sense Earth’s fields and use them for orientation.
However, Cry4 proteins belong to a bigger class, and not all of them might interact with magnetic fields. This is why researchers decided to study the muscles, brains, and retinas of 39 birds belonging to the zebra finch species. Then, they studied the production of Cry4 and two other related proteins, Cry1 and Cry2. The levels of the latter proteins fluctuated during the day, while Cry4 levels remained constant.
Birds need to have their orientation skills up anytime, so they probably use this magnetic compass of theirs both during daytime and nighttime. These findings are backed up by similar results on robins, who used the Cry4 protein over a complete cycle of 24 hours. All the researchers were then summed up in a paper in the Journal of the Royal Society Interface.
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