- Dozens of animal species, from ants to whales, have well-documented abilities to detect the geomagnetic field and use it for orientation and navigation.
- After some false starts, researchers may have now located the organs for this magnetic sense, and they are finally understanding the physics that underpins it.
- Some animals may use microscopic magnetic particles to detect magnetic fields; others might harness quantum effects on certain pigments in the eye.
For what must have felt like an interminable six months back in 2007, Sabine Begall spent her evenings at her computer, staring at photographs of grazing cattle. She would download a satellite image of a cattle range from Google Earth, tag the cows one by one, then pull up the next image. With the help of her collaborators, Begall, a zoologist at the University of Duisburg-Essen in Germany, ultimately found that the unassuming ruminants were on to something. On average, they appeared to align their bodies with a slight preference toward the north-south axis. But they were not pointing to true north, which they could have located using the sun as reference. Instead they somehow knew how to orient themselves toward the magnetic north pole, which is hundreds of kilometers south of the geographic pole, in northern Canada.
A follow-up study found more evidence that animals as large as cows can react to the earth’s magnetic field: the aligning behavior vanished in the vicinity of high-voltage power lines that drowned out the relatively subtle signals coming from the planet.