Birds Do It, Bats Do it

Birds Do It, Bats Do It

Do our bodies contain an ancestral but atrophied gift for "seeing" magnetic fields? Birds navigate with the aid of a protein in their retinas called cryptochrome, which is sensitive to the Earth's magnetic field and therefore serves as a built-in compass. And it's not just birds that can do this trick but bats, turtles, ants, mole rats, sharks, rays, and flies. What's more, the molecule that confers the sensitivity is "an ancient protein with versions in all branches of life," including humans. Drosophila flies can be trained by artificial magnetic fields to search for food in a particular direction. Remove the gene responsible for their cryptochrome and they lose the ability -- but it can be restored by giving them human cryptochrome.

Even if human bodies contain a retinal molecule that is sensitive to the angle of the magnetic field, that doesn't mean that humans have (or still have) a sensory and neural apparatus that permits them to translate the molecule's sensitivity into a useful perception. There has been limited, and disputed, research into whether some people have a robust sense of direction that can't be explained by visual cues. The investigation is complicated by the possibility that any magnetic/directional sense we do have is tied to the retina and therefore hard to untangle from ordinary visual clues. Still, the possibility of these mysterious ninja talents always enchants me.

Related: From a link at the same site, an article about echolocation and the "the brain’s extraordinary flexibility and power to squeeze perception out of a range of information streams, some of which are normally non-conscious to us." Some great video there:

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