Scientists summarise the methods used to explore how the Earth’s magnetic field influences the behaviour of various animal species. This review is an ideal starting point for scientists wishing to enter this fascinating but poorly-understood topic in modern sensory biology.

For more than 50 years, researchers have noted that the Earth’s magnetic field can affect the behaviour of a wide range of species. But, despite decades of study, the precise makeup of this “magnetic sense” is still unknown. A thorough overview of this interdisciplinary topic has now been produced by Will Schneider, Richard Holland, Oliver Lindecke, and others from Bangor University in Wales, Institute for Biology in Oldenburg, Germany, emphasising the methodology used. The EPJ Special Topics journal has now published this piece.

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This magnetic sense, or ‘magnetoreception’, was first noticed in birds, particularly in migratory songbirds. It has now been observed in many other species including mammals, fish and insects. However, the exact relationship between the magnetic field and the behaviour is difficult to pin down because it can be masked by other environmental factors.

Experiments must be very carefully designed if their results are to be statistically sound.
“We aim to provide a balanced overview for researchers who wish to enter this exciting area of sensory biology,” said Schneider. He and his co-authors outlined a range of methods that are used to deduce whether an animal’s behaviour is affected by a magnetic field.

These include using GPS to mark animals’ alignment with the Earth’s field during normal activities, such as cows grazing; observing behaviour after tissues thought to be responsible for magnetoreception have been removed, or genes knocked out; and attaching small magnets on or near the animals’ bodies to disrupt the mechanism.

Further work by animal physiologists, neuroscientists, geneticists and others will also be necessary to truly understand this phenomenon.

And this research is not only of academic interest. “Understanding animal magnetoreception will help us to protect animals released into unknown environments in the wild,” added Lindecke.