Certain bird species such as zebra finches and European robins have the ability to detect the earth’s magnetic field. No wonder they can easily navigate even when they fly off to unfamiliar places and can migrate thousands of kilometers without any hassles when seasons undergo a change.
Previously, it was assumed that birds relied on their beak cells, rich in iron, to act as a microscopic compass. However, recent research has unveiled that a bird’s eye has specific proteins which allow them to detect the earth’s magnetic field. One of the studies, published in the Journal of the Royal Society Interface in March of this year, examined zebra finches, whereas the other study, published in the
Current Biology journal in January, focused on European robins. Though the subjects of the two studies were different, the conclusions are the same.
The retina of a bird eye contains Cry4, a protein sensitive to light. Cry4 belongs to cryptochromes, the protein class responsible for biological sleep cycles and circadian rhythms. Some of the proteins in this group can also react to the magnetic field, and thus, help birds sense it.
Peter Hore of the University of Oxford is excited about the discovery, claiming that papers like these are definitely needed more.
The zebra finch study was conducted by Atticus Pinzon-Rodriguezm, a biologist at a Sweden university and his team. They studied the retinas, brains and muscles of zebra finches in order to detect the presence of Cry1, Cry2 and Cry4, the proteins involved in quantum interactions. During an entire day, the levels of the first two proteins varied according to a rhythmic pattern, but Cry4 levels remained the same, indicating a steady protein production. Rachel Muheim, also on the zebra finch team, explained that birds can supposedly use the magnetic compass at any time, regardless of whether it’s day or night.
The European robin team had similar results to share. They also concluded that Cry4 levels were constant throughout the day, but they tended to rise during migratory period. Moreover, this protein was found in an area, receiving a significant amount of light – the position could help the protein work as a compass.
So while there is plenty of evidence, there is still no concrete proof said Henrik Mouritsen, a participant of the robin study who is associated with the Institute of Biology and Environmental Sciences in Oldenburg, Germany. He also stated that birds without Cry4 protein should be examined as well for presence of an internal compass.
If these conclusions are true, then this is the first time that a magnetic field detecting molecule has been found in animals.