Scientists have known for more than 60 years that animals can sense the Earth’s magnetic field, and there is a wealth of behavioural evidence supporting their use of this cue as a navigation mechanism. But despite this evidence, there’s no consensus as to how animals actually sense the magnetic field.
Magnetic cues appear to be used by animals in all sorts of circumstances, not simply for long-distance navigation. Magnetoreception is used for orientation in invertebrates, fish, amphibians and reptiles. Mammals use it in behaviour such as nest building and hunting, as well as homing.
