Iron-rich tissue may serve as biological compass
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. “They're the biological equivalent of the elusive Higgs boson.”
The first demonstration of an animal’s internal compass dates to nearly half a century ago, when experiments showed that caged robins turn when exposed to rotating magnetic fields. Other birds, as well as sea turtles and some fish and amphibians, share this remarkable ability.
But the cells behind the unusual sense — which humans either lack or aren&