A newly discovered protein in bird’s eyes has shed light on how our winged friends can navigate the planet so well. It turns out this protein gives birds a 6th sense that allows them to “see” the Earth’s magnetic fields.
The Earth’s magnetic fields, thought to be created from deep within the planet’s core, are invisible to most human eyes.
A flow of liquid Earth-core iron generates electric currents which then produce magnetic fields. (The moon also creates a weak magnetic field with its gravitational pull on our salty oceans.)
Stunning new SWARM images have allowed us to see the Earth’s magnetic fields in more clarity than ever, but birds are already more advanced than us at least in one regard. They can see these magnetic fields without any help from scientific instruments.
Even with highly accurate tracking scientists say that the magnetic field is very difficult to pinpoint. “It’s a really tiny magnetic field. It’s about 2-2.5 nanotesla at satellite altitude, which is about 20,000 times weaker than the Earth’s global magnetic field,” Nils Olsen, head of geomagnetism at the Technical University of Denmark says.
However, birds use the Earth’s magnetic fields to guide them around the planet with ease. Scientists discovered this looking at two bird species – robins and zebra finches.
Cry4 a special protein in the lens of birds’ eyes, is in a class of proteins called cryptochromes. They are photoreceptors sensitive to blue light, found in both plants and animals. These proteins play a role in regulating circadian rhythms.
These cryptochromes are also believed to help birds orient themselves in space, giving them what many of us would consider a superpower – magnetoreception. The visual ability to detect magnetic fields may also work due to quantum coherence within the blue light spectrum.
Scientists at Lund University in Sweden confirmed the presence of three of the magnetoreceptive proteins – Cry1, Cry2 and Cry4 – in the bodies of zebra finches, and similar research conducted at Carl von Ossietzky University Oldenburg in Germany, arrived at similar results after studying the presence of Cry4 in robins. The proteins seem to be concentrated in the part of the bird’s eyes that receive a lot of light –meaning that they would navigate better according to circadian rhythms as well.
What’s even more fascinating, is that the scientists who studied finches and robins believe that other animals, perhaps all of them including humans, have magnetic receptors that can pick up on magnetic fields as well. This means we all have an ability to see an “invisible” magnetic field, not just sense it.
Moreover, as research confirms that the Earth’s magnetic fields are likely to flip, we’ll all be just fine. We shouldn’t expect a geomagnetic apocalypse, but we might need to use this 6th sense exemplified in birds’ eyes as a way to navigate ourselves.