Cows truly have animal magnetism

Birds do it, bees do it, and so, apparently, do ... cows?   

No, it’s not that. We’re talking about sensing the Earth’s magnetic field.

German scientists using satellite images posted online by the Google Earth software program have observed something that has escaped the notice of farmers, herders and hunters for thousands of years: Cattle grazing or at rest tend to orient their bodies in a north-south direction just like a compass needle.

Studying photographs of 8,510 cattle in 308 herds from around the world, zoologists Sabine Begall and Hynek Burda of the University of Duisburg-Essen and their colleagues found that two out of every three animals in the pictures were oriented in a direction roughly pointing to magnetic north.

The resolution of the images was not sufficient to tell which ends of the cows were pointing north, however. Asked if he had ever observed such behavior in cows, dairy farmer Rob Fletcher of Tulare said, “Absolutely not.” But, he added, “I don’t spend a lot of time worrying about stuff like that.”

Similar results were found in field studies of 2,974 red and roe deer in the Czech Republic, the researchers reported Tuesday in the Proceedings of the National Academy of Sciences.

The researchers had been studying magnetism in smaller animals and were looking for a way to extend their work to larger species. Cows are known to align their bodies facing uphill, facing into a strong wind to minimize heat loss or broadside to the sun on cold mornings to absorb heat, but the fact that the pictures were taken at many locations, at different times of day and in generally calm weather minimized the impact of environmental factors, the researchers said.

Researchers have long known that certain bacteria, birds, fish, whales and even rodents have minute organs in their brains containing particles of magnetite that can act like a compass. But the new results are the first hint that larger land-based mammals may also have such organs, said biologist Kenneth J. Lohmann of the University of North Carolina at Chapel Hill, who was not involved in the research.

The findings are “very interesting and not at all implausible,” said Caltech geobiologist Joseph Kirschvink, who was also not involved in the research. “We have to remember that whales are descended from a common ancestor of [cows], so this is not a surprise given what we know about whales.” And, he added, “this is an incredibly neat use of Google Earth. This is a study we would not have dreamed about doing five years ago.”

Bats, birds, bees and whales all use their magnetic sense to help navigate. Kirschvink recently reported, for example, that if a pulsing magnetic field is applied to bats perpendicular to the Earth’s field, the animals will change the direction of their flight by 90 degrees.

What the benefit could be for cows, however, remains a mystery. It might help them find their way home, experts said, or perhaps it is simply a vestigial sense that is no longer used for any purpose.

Furthermore, the authors noted, no one has examined cows or deer to determine whether their brains contain magnetic particles. Experts acknowledged that the research almost certainly has no practical applications.

-- Thomas H. Maugh II

Photo: Dave Martin/Associated Press

Comments

[Ben Bangerter]

Idiots, The sun warms there flanks

[PJR]

This is very interesting and may be very important. It would be interesting to observe this over a much longer time period. I do believe that there is evidence that the earths magnetic field is in the process of 'flipping' from north to south, albeit over a long time period, i.e eventually a compass would point south rather than north. I am interested to know if animals, insects and bacteria could acts as indicators of the shift in the polarity of the earth?

[Erm...]

Maybe they just like the sun on their flanks?

[Moe]

If wind in the areas looked at typically blows east to west or vice versa, then the behaviour could be to allow the cattle to better see, smell or react to predators who like to approach from downwind. It may have nothing to do with a compass effect at all, but be based on the wind at the time the images were taken, or habits formed by the typical wind direction in the areas viewed.

If could also be caused by human choices regarding the placement of any of a variety of farm features. I wouldn't jump to the conclusion that cattle have an internal compass.

If it's true that cattle do this, I'm sure many children have noticed it and been rebuffed or ignored by their parents.

[Joseph]

This argument does not follow logically. Just because there were a statistically significant number of cows oriented north-south does not mean that they can detect the earth's magnetic field. There could be some other cause. For example, they could always try to be perpendicular to the sun.

Plus, what is the evolutionary motivation for a magnetic sense in cows? Maybe for migration, but why does that affect how they orient themselves when standing or resting?

[Brien Comerford]

It's inexplicable that people are still eating the flesh of cows, pigs, lambs, chickens and our other fellow creatures in the 21st century. It's almost tantamount to cannabalism.