How do birds nevigate?
Yet Earth's magnetic field is very week. It ranges from approximately 30 to 60 millionths of one tesla. By comparison, magnetic resonance imaging, or MRI, uses magnetic fields from 1.5 to 3.0 tesla
So scientists unsure exactly how birds do it.
New research finds that a photochemical compass may simulate how migrating birds use the magnetic field, along with light, to navigate.
One theory for how it all works has been that photoreceptors in a bird's retina absorb light, which causes a chemical reaction that, in turn, produces a short-lived photochemical species whose lifetime is sensitive to the magnitude and direction of a weak magnetic field.
The idea is supported by the fact that blue light photoreceptors have been detected in retinas of migratory birds when they perform magnetic orientation. However, it has not been confirmed that a magnetic field as we ...more