The next time you're lost in cottage country, look for a deer or a cow — they can tell you directions, scientists say.
Researchers in Germany and the Czech Republic have found that deer and cows have an innate magnetic sense, as they tend to align themselves with the Earth's magnetic field lines when at rest. When grazing or resting, the animals were found to face either magnetic north or south, according to the report that appears in Monday's edition of the Proceedings of the National Academy of Sciences.
In their study, researchers looked at Google Earth satellite photographs of 8,510 cattle in 308 pastures and plains around the world, as well as field data collected on nearly 3,000 deer in 225 locations in the Czech Republic.
Wind and sunlight tend to have a big effect on positioning, the researchers said, as the animals tend to orient themselves in ways that best take advantage of available warmth. However, those effects were discounted in the positioning study because they varied greatly across geographies.
That meant a magnetic sense was the most logical rationale, the researchers wrote. Although ranchers have long known that a herd of cattle tend to face the same direction, no one has ever noticed the specific direction they face.
"Amazingly, this ubiquitous phenomenon does not seem to have been noticed by herdsman, ranchers or hunters," the report says. "Because wind and light conditions could be excluded as a common denominator determining the body axis orientation, magnetic alignment is the most parsimonious explanation."
The scientists, led by Sabine Begall of the University of Duisburg-Essen in Germany, pointed out that in previous studies, birds, turtles and salmon have all been proven to use magnetic guidance in their migration. Several rodent and one bat species have also been shown to use an innate magnetic compass.