High-voltage power lines short-circuit cows' satnav

Published on Monday 16 March 2009 20:58

RATHER than just following the herd, cows have their own in-built sat-nav system pointing them in a north-south alignment when grazing or resting.

However, researchers who revealed this fact last year have now found that cows grazing under high-voltage power lines running east to west will direct themselves in that direction.

But to complicate matters further, cows chewing the cud under north-east/south-west or north-west/south-west power lines face random directions.

Hynek Burda and Sabine Begall of the faculty of biology at the University of Duisburg-Essen in Germany led a research team who studied cows and deer using satellite and aerial images.

Their findings, published today in the Proceedings of the National Academy of Sciences, reveal that whereas last year research indicated the animals' north-south orientation was in response to the earth's magnetic fields, further investigation shows the animals may be responding to magnetic effects since power lines also produce a magnetic field.

The research also found the effect was most noticeable close to the power lines but declined the further away the animals were from their magnetic field.

A Google mapping tool was used to study photos of some 300 herds of cattle around the world.

The earth's magnetic field is thought to be a factor in how birds navigate, flying thousands of miles during migration but finding their way home each year.

Other animals, such as certain species of birds and most bees possess a similar trait which helps guide migration.