Go West, Young Cow?

The report (http://www.newsvine.com/_news/2008/08/25/1784447-cows-seem-to-know-which-way-is-north) that some German and Czech scientists have used more than 8500 images of cattle and deer herds from Google Earth to reveal that the animals (whether grazing or resting) generally orientated themselves along the north-south axis is intriguing. It suggests that such cattle (in addition to pigeons) can detect the Earth's electromagnetic field. Why they do this appears less certain but it could be simply related to prevailing wind direction (i.e. not true field detection?) although the fact that the phenomenon appeared in a range of geographical locations possibly rules this out. One thing is certain, if you get lost in a fog without a compass, you could do worse than take your directions from cattle encountered in fields.