Interesting work is reported in a NY Times story about this.
Many animals rely on the magnetic field for navigation, and researchers have often wondered if people, too, might be able to detect the field; that might explain how Polynesian navigators can make 3,000-mile journeys under starless skies. But after years of inconclusive experiments, interest in people’s possible magnetic sense has waned.
That may change after an experiment being reported last week by Steven M. Reppert, a neurobiologist at the University of Massachusetts Medical School, and his colleagues Lauren E. Foley and Robert J. Gegear. They have been studying cryptochromes, light-sensitive proteins that help regulate the daily rhythm of the body’s cells, and how they help set the sun compass by which monarchs navigate.Because the DNA sequence of one of the butterfly's cryptochrome genes is similar to that of a human gene (CRY), they transplanted the human gene into fruitflies and report their results.
But it is simply preposterous, we think, to give this the usual hyperbolic spin. Humans move too slowly for much of this to make sense, even if the gene does code for a useful magnetosensor. As with any other 'chaos' formation, if our direction is even slightly off, then we'd be wildly off over any distance--as off as if we had no magnetic sense. Going very long distances would not be practical with this sense and we know from centuries of direct evidence that sailors got lost and drowned because without real instruments (even with the stars available) it wasn't possible. No fitness advantage there, til the astrolabe-gene came along. Did the magneto-gene evolve in a very non-Darwinian way, millions of years ago, to lay in waiting til the Age of Sail?
Our own personal (lack of) sense of direction (one of us could get lost just going out to pick up the paper) is also clear proof of the Bollocks Principle: don't believe what you read about science without first thinking seriously about it.