Do animals really use magnetism in any interesting way to navigate?

We think so, but the subject is still under investigation. Certain typoes of bacteria called Magnetotactic Bacteria have internal bodies composed of lodestone ( magnetite) and there is no chemically sensible reason why bacteria would have favored this element over all others unless the magnetic properties of this element were important. Biologists think that bacteria use these as built-in magnetic compasses to sense where 'down' is so that they can find food.

For a long time it has been thought that 'homing pigeons' use some kind of magnetic sense to navigate when they can't use the sun or stars, but this is still considered to be somewhat controversial because a specific organ acting like a magnetic compass has not been found.

So, only bacteria seem to have both an organ and a need for magnetic navigation.

Return to the Ask the Space Scientist main page.

All answers are provided by Dr. Sten Odenwald (Raytheon STX) for the