The mystery behind animal magnetism and power lines
Animals have the ability to navigate by detecting both the strength of the magnetic field emitted by the Earth's liquid core, and the angle at which the field meets the Earth. And research has shown that cows and deer, for example, orient themselves in a north-south alignment. But a Czech-German team of researchers has discovered that the animals' navigating skills go awry when high-voltage power lines are in the area. This latest discovery provides further evidence that animals respond to magnetic effects, particularly because power lines generate a magnetic field. The findings have been published in the Proceedings of the National Academy of Sciences.
How does the animal brain process magnetic information? Past studies have shown that some species have particular brain areas that respond to magnetic information. These areas may also have nerve cells that detect changes in the magnetic field. And the presence of the naturally magnetic mineral magnetite in the brains of some animals triggers magnetoreception (i.e. the ability to detect a magnetic field, to perceive direction, altitude or location).
Professor Hynek Burda from the University of Duisberg-Essen in Germany proposed in a research study last August that the north-south orientation occurred in response to the Earth's magnetic field. Using Google Earth to prove this theory, the researcher found that herds pointed either north or south.
However, Professor Burda and his colleague Dr Sabine Begall took the research one step further and found that if power lines run from east to west, the grazing cattle will line up in that manner as well. In contrast, the cattle and deer will graze in random directions if they are under northeast-south-west or northwest-southeast power lines. Their built-in 'magnetic compass', which controls their behaviour, gets out of whack the closer the animals are to power lines.
'Extremely low-frequency magnetic fields (ELFMFs) produced by high-voltage power lines interrupt the alignment of the bodies of these animals with the geomagnetic field,' the co-authors of the study wrote. 'Body orientation of cattle and roe deer was random on pastures under or near power lines. Moreover, cattle exposed to various magnetic fields directly beneath or in the vicinity of power lines trending in various magnetic directions exhibited distinct patterns of alignment.'
The Czech-German research team used satellite and aerial images to assess the cows and deer. 'The disturbing effect of the ELFMFs on body alignment diminished with the distance from conductors,' the researchers said. 'These findings constitute evidence for magnetic sensation in large mammals as well as evidence of an overt behavioural reaction to weak ELFMFs in vertebrates,' they added. 'The demonstrated reaction to weak ELFMFs implies effects at the cellular and molecular levels.'
The other institutions participating in the study were the Czech University of Life Sciences, the Academy of Sciences of the Czech Republic and Charles University in Prague.