Trout nose cells follow magnetic fields

Cells plucked from a trout’s snout swivel like tiny compasses to line up with a nearby magnet. That sensitivity, credited to iron inside the cells, could explain how fish, birds and other animals sense Earth’s magnetic field — a long-standing mystery among biologists.

“For decades scientists have been searching for the cells responsible for magnetosensation,” says David Keays, a neuroscientist at the Research Institute of Molecular Pathology in Vienna who wasn’t involved in the new study.