Cows and Magnetic allignment

Google earth's mapping has thrown up an info. Researchers noted that Cattle shown to align north-south while grazing. This seems to be applicable to certain other species like deer etc.
The conjucture being that the earths magnetic field is being used for this subconscious alignement.
Does that mean that magnetic fields have an effect on the Human Beings also.
Well we are not cattle ... but then is there any harm in having such an attribute.
As per vaastu our sleeping position should be North South - maybe there is some strength in that. So our ancestors have also observed some relationship.