Why do cows…
… often stand in a field facing the same direction? The reason might seem obvious—but it is wrong!
They all face the same way, especially when grazing. I have known why for a long time now: because of the wind. Could anything be more obvious? They all face the direction from which the wind is coming, to offer least resistance to it. Is there any room for debate?
Apparently there is:
Sabine Begall of the University of Duisburg-Essen, Germany, examined Google Earth images and found that “whether grazing or resting, these animals face either magnetic north or south”. Since the direction of the wind and sun “varied widely where the images were taken”, it’s reasonable to suggest they’re reacting to the planet’s magnetic influence. Professor Begall found a similar preference in deer, who she believes must also be sensing the Earth’s magnetic field. The results were published in the Proceedings of the National Academy of Sciences, where the authors demonstrate “by means of simple, noninvasive methods (analysis of satellite images, field observations, and measuring ‘deer beds’ in snow) that domestic cattle (n = 8,510 in 308 pastures) across the globe, and grazing and resting red and roe deer (n = 2,974 at 241 localities), align their body axes in roughly a north–south direction.” Actually the team was unable to reliably distinguish between the head and rear of the cattle, but could tell that the animals tended to face either north or south.
So we have to assume that cattle and deer, like birds, bats, a number of rodents, and even butterflies (!) have a sixth magnetic sense, which might be quite common in the animal kingdom — but is missing in homo sapiens, who have to build compasses and GPS to catch up.
In the paper Begall excludes the explanation that the animals may be aligning to maximise heating from the sun. On fields close to the poles, where the difference between the direction of magnetic north and true north is greatest, the animals should be aligned to true north to achieve the greatest effect. But they are oriented more to magnetic north than to geographic. Begall also refutes the idea that the cattle are trying to minimise their profile against the wind. Apparently she found no correlation with body alignment: if wind was a factor there would be more random alignments, rather than a global preference to point north-south.
Case closed? Not quite. The original Begall et al. paper appeared in 2008, and was extensively covered in the media. But then 2011 in this PhysOrg.com article the authors were taken to task. I enjoy these scientific controversies so much that I need to share some of Bob Yirka’s “Cow row” piece with you:
Sometimes, scientists hard at work in their field, come across findings that they cannot explain, and instead of simply writing a paper describing what they’ve seen, they instead choose to write a paper describing what they think their observations have shown. Case in point, back in 2008, a group of guys with Biology and wildlife backgrounds were apparently sitting around looking at pictures taken by Google Earth, when they noticed that there seemed to be a pattern in the way some cows in a pasture aligned themselves. After looking at more pictures, a larger pattern began to emerge. Oddly enough, the cows seemed to be aligning themselves with the Earth’s magnetic field lines. The group, led by Hynek Burda wrote up a paper describing what they’d found and had it published in the Proceedings of the National Academy of Sciences. Later, the team did additional research and found that no such kinds of lining up occurred around power lines which they thought might disrupt the cow’s ability to sense magnetic fields.
Because the whole thing was technically based on science, another group decided this year to see if they could replicate what the first group had found. Unfortunately, this second group failed to find any real good examples to back up the claims made by the first, and said so in their paper published in the Journal of Comparative Physiology A.
The first group, clearly annoyed at the findings of the second group, asked to have a look at what they had been looking at in basing their findings, and lo and behold, found, at least to their eyes, all manner of errors, not the least of which was that the second group seemed to be looking at hay bales, barns and other inanimate objects in addition to the cows that were supposed to be the focus of the research. They also found that the second group had apparently been looking at individual cows, rather than at herds overall. This led them to conclude that the work done by the second group was flawed and thus their findings were not valid.
Luckily, others have also had a look at the work that both teams did and have done some looking of their own, and most apparently, at least at this point, are siding with the first team, saying that there does indeed seem to be some evidence that shows that cows, for whatever reason, do indeed tend to align themselves with the Earth’s magnetic field lines. Which means, of course, we can all smile inwardly and get on with our day, safe in the knowledge that the world’s scientists are hard at work trying to solve the great mysteries of our time.
Driving past a field of cattle (above), recently in Cornwall, my friend John proposed a different theory: cows are, as you might know, herd animals, and as such tend to imitate the behaviour of each other—usually following the example of a dominant member. Also, since they are grazing they keep moving to new pastures, and don’t do this aimlessly. They tend to follow a few leaders. I find this explanation very plausible, though it would not explain the preponderantly north-south orientation, if the satellite observations are indeed valid.
Finally I want to challenge you to guess why the cows in the above picture have gathered together and are all looking in the same direction. Really, try to think of an explanation before you click this YouTube link for the solution.
