Accordingto popular folklore, many animals are smarter than they appear. Dogsbark before earthquakes; cattle predict rainfall by sitting on theground. But cattle may have another hidden talent in telling whichway is north.

   Smallanimals such as mole rats living underground are known for the use ofmagnetism to navigate. Dr. Begall and her colleagues wanted to knowwhether larger mammals also have the ability to perceive magneticfields. They investigated this possibility by studying images ofthousands of cattle captured on Google Earth, a website that stitchestogether satellite photographs to produce an image of the Earth’ssurface.

   Grazinganimals are known to orient themselves in a way that minimizes windchill from the north and maximizes the warmth of the sun when theyare cold. The researchers therefore had to study a lot of cowsgrazing in lots of different places at different times of day, inorder to average out these factors and see whether cattle could actlike compass needles.

   Theresearchers concluded that cattle do generally orient themselves in anorth-southdirection. This north-southpreference has also been noted in flies, termites and honeybees. Butunfortunately, even the high resolution of Google Earth is notpowerful enough to tell which end of the cow is its head, and whichits tail. The researchers were therefore unable to answer theirresearch questions of whether cattle prefer to look north or south,and whether that differs in the northern and southern hemispheres.