Cattle partake in some directional grazing. Have you ever noticed that herds of grazing animals all face the same way? Images from Google Earth have confirmed that cattle tend to align their bodies in a north-south direction. Wild deer also display this behavior – a phenomenon that has apparently gone unnoticed by herdsmen and hunters for thousands of years.
In the Proceedings for the National Academy of Sciences, scientists say the Earth’s magnetic fields may influence the behavior of these animals. The Earth can be viewed as a huge magnet, with magnetic north and south situated close to the geographical poles. Many species – including birds and salmon – are known to use the Earth’s magnetic fields in migration, rather like a natural GPS. A few studies have shown that some mammals – including bats – also use a “magnetic compass” to help their sense of direction. This sense may be quite widespread in the animal kingdom.
The researchers surveyed Google Earth images of 8,510 grazing and resting cattle in 308 pasture plains across the globe. The scientists were unable to distinguish between the head and rear of the cattle but could tell that the animals tended to face either north or south. Their study ruled out the possibility that the sun position or wind direction were major influences on the orientation of the cattle. In Africa and South America, the cattle were shifted slightly to a more north-eastern-south-western direction. But it is known that the Earth’s magnetic field is much weaker there. The researchers also recorded the body positions of 2,974 wild deer in 277 locations across the Czech Republic. Their fieldwork revealed that most grazing and resting deer face northward. About one-third of the deer faced southward.