The most surprising science story of 2008 has returned to the news today, with a follow up to the study that appeared to show cows have a magnetic sense.

As we reported last year:

An analysis of more than 8,000 cows claims they have a statistically significant preference to align themselves in a north-south direction. The team behind this study has also found a similar preference in deer, and believes the animals must be sensing the Earth’s magnetic field.

Of course the researchers realised a claim like this would likely meet with some scepticism. So they decided to look at cows that happened to live near power lines, and the magnetic fields that come with them. As Nature’s story from last year noted, at-the-time-unpublished work seemed to show that cows near power lines were not aligned north-south.

This work, utilising satellite and aerial photographs of cows – and field observations of deer – near power lines has now been published.

“Whatever the underlying mechanism, our results provide further evidence that the recently described spontaneous directional preference in grazing and resting cattle and deer represents a case of magnetic alignment,” write Hynek Burda, of the University of Duisburg-Essen, and colleagues in PNAS. “The fact that animals grazing under or near high-voltage power lines were not commonly aligned but exhibited distinct alignment patterns beneath or in the vicinity of power lines trending in various magnetic directions clearly rules out a role of the sun compass in alignment behaviour of ruminants.”

The article will be available here later this week.

Headline watch

How Udderly Odd – TinySci

Power lines spark interest over effect on animals – Yorkshire Post

High-voltage power lines short-circuit cows’ satnav – Scotsman

No bull: High voltage power lines can affect which direction grazing cows choose to face – KFSM

Image: paper author J. Cerveny