Postprint version. Published in Journal of Magnetism and Magnetic Materials, Volume 15-18, Issue 3, January 1, 1980, pages 1562-1564.
NOTE: At the time of publication, the author Richard B. Frankel was not yet affiliated with Cal Poly.
The definitive version is available at https://doi.org/10.1016/0304-8853(80)90409-6.
Magnetotactic bacteria that orient and swim in a preferred direction in the geomagnetic field contain sufficient single domain magnetite to constitute a biomagnetic compass.