Bioessays. 2006 Feb;28(2):157-68. doi: 10.1002/bies.20363.


The vector of the geomagnetic field provides animals with directional information, while intensity and/or inclination provide them with positional information. For magnetoreception, two hypotheses are currently discussed: one proposing magnetite-based mechanisms, the other suggesting radical pair processes involving photopigments. Behavioral studies indicate that birds use both mechanisms: they responded to a short, strong magnetic pulse designed to change the magnetization of magnetite particles, while, at the same time, their orientation was found to be light-dependent and could be disrupted by high-frequency magnetic fields in the MHz range, which is diagnostic for radical pair processes. Details of these findings, together with electrophysiological and histological studies, suggest that, in birds, a radical pair mechanism located in the right eye provides directional information for a compass, while a magnetite-based mechanism located in the upper beak records magnetic intensity, thus providing positional information. The mechanisms of magnetoreception in other animals have not yet been analyzed in detail.

Publication types

  • Review

MeSH terms

  • Animal Migration / physiology*
  • Animals
  • Electrophysiology
  • Ferrosoferric Oxide
  • Light
  • Magnetics*
  • Models, Biological*


  • Ferrosoferric Oxide