The amazing rainbow trout fish compass

Picture of a rainbow trout.

How do rainbow trout navigate?

New Zealand biologists have found that they have “a magnetic compass in their noses,” reports New Scientist magazine.

Many birds and reptiles and some mammals can orient themselves relative to earth’s magnetic field.

But scientists had never identified north-sensing cells, cells believed to contain the magnetic mineral magnetite.

In trout, researchers at the University of Auckland discovered a nerve fiber in the fish’s face that fires when exposed to a magnetic field.

Tracing the fiber led them back to the fish’s nose, where they found nerve cells that contain magnetite.