Why do cows eat facing north

He added: "We need to think about some really fundamental things that this sensory ability provides in animals. Most Popular Now 56, people are reading stories on the site right now. BBC News Updated every minute of every day. One-Minute World News. News Front Page. E-mail this to a friend Printable version. Cattle partake in some directional grazing. This sense may be quite widespread in the animal kingdom.

Forest dormitory: Deer "beds" are seen in a line. Dr Sabine Begall. A strong wind or sunlight on a cold day have typically proved more the "exceptions to the rule" that might cause large animals to face away from magnetic north-south. The data on 2, deer came from direct ground observations and photos in the Czech Republic.

Researchers also examined fresh beds left by resting deer in the snow, where the animals had sought shelter deep in the forest away from the wind. Both cattle and deer faced a more magnetic north-south direction rather than geographic north-south, Earth's magnetic poles do not line up perfectly with the North and South Poles.

Cows are unique in that they have fewer teeth than other animals. Plant materials sometimes contain tough stems, but because a cow chews food in a side-to-side motion, the molars shred the grass into small pieces that are more easily digested.

When grazing or resting cows tend to align their bodies with the magnetic North and south Poles? By analyzing the images, the team found that cows tend to face either magnetic north or south when grazing or resting.

Cows tend to stand and graze around a field facing the same way as each other to avoid threats to, and within, the herd. Cows are herd animals and stick together to reduce the threat from predators. Facing the same way also cuts down on conflict in the herd because it avoids head-to-head confrontations. The four compartments allow ruminant animals to digest grass or vegetation without completely chewing it first. Instead, they only partially chew the vegetation, then microorganisms in the rumen section of the stomach break down the rest.

The group, led by Sabine Begall of the University of Duisburg-Essen in Germany, found that cows were not positioning themselves willy-nilly in their pastures; they aligned their bodies in a north-south direction. Begall and colleagues thought the most likely explanation for their finding was magnetic alignment. This is a simple directional response to the earth's geomagnetic field. Some animals prefer to orient their bodies, especially when resting, in a certain direction with respect to the north-south axis.

Magnetic alignment has been found in diverse animals, including honeybees, fruit flies, zebrafish, bats, foxes, and some rodents. More familiar are the animals that use their magnetic sense as a cue in long migrations, such as sea turtles and pigeons. The detection and use of the planet's magnetic field for navigation is a well-accepted and well-studied phenomenon.

Simple magnetic alignment is less readily acknowledged. This could be because magnetic alignment is a subtler behavior or because we don't really know why animals do it. And it could be due to the difficulty in observing magnetic alignment in many animals. That's where Google Earth comes in. Its widely accessible collection of satellite images allowed scientists a bird's-eye view of how cows were aligned with respect to Earth's magnetic field.