Many migratory animals have the Earth’s magnetic fields tattooed on their skin, embedded in the bones, grafted into the muscles and tendons. This has long been intuited by popular wisdom: there is no other way to explain how tiny animals are able to navigate thousands of miles without getting disoriented along the way.
Or rather, “there was” no other way to explain it. More interesting hypotheses have been proposed in recent years, of course. The most promising tell us about light-sensitive proteins (the ‘cryptochromes’); that is, that where really were those ‘organic compasses’ that have marveled us for centuries was in the eyes. The problem is that until now we were not very clear about what those specific proteins were like and what physical properties supported those machinery.
Quantum effects in the fundus of the eyes
Peter Hore and his team at the University of Oxford have studied cryptochrome 4 (CRY4), a protein that is expressed in the visual cells of European robins, in detail. In doing so, they discovered that said protein had magnetic properties that could act as magnetic compasses dependent on light. It sounds as complicated as it sounds.
So much so that it relates very interesting quantum effects. For this reason, today, ‘Nature’ dedicates a study in which it explains how this mechanism allows a chemical reaction that, through certain optical effects, amplifies magnetic signals and could articulate a magnetic system accurate enough to allow robin’s migrations.
And not only that, they have discovered that the CRY4 is more sensitive to magnetic fields in these types of migratory birds than in chickens. or non-migratory pigeons. Something that, in the absence of better evidence, supports the thesis that these proteins are important from an evolutionary point of view.
Because, indeed, we need better evidence. Specifically, we need to see directly how the protein works in the eyes of these types of birds. In other words, we have discovered a piece: we need to know how it engages in the complete mechanism. And discovering it will be very interesting because it will allow us to advance our knowledge of what bioengineering is capable of achieving.
Image | Alfred Kenneally