We have the right stuff to sense magnetic fields - New Scientist - New Scientist

We have the right stuff to sense magnetic fields: The mutant flies were trained to associate a sugar reward with a magnetic field. When given the option to fly down either a magnetised or non-magnetised arm of a maze they opted for the magnetised one. Flies genetically engineered to lack cryptochrome altogether were indifferent to the magnetic field in one arm and were evenly distributed down both arms of the maze. Apparently, fruit flies have no problem using human cryptochrome to sense magnetic fields, which implies humans have the hardware to do the same, but for some reason do not activate the ability, says Reppert.