In 2008, a team of scientists led by Sabine Begall used Google Earth satellite images to study something no one had thought to check before: which direction do cows face when they graze? The researchers analyzed 8,510 cattle in 308 pastures spread across multiple continents. What they found was striking.
The cattle were not facing random directions. Instead, they tended to align their bodies along a north-south axis. The pattern appeared in herds across Europe, Africa, Asia, and the Americas. It held during the day and at night, in sunny weather and under overcast skies. Field observations of wild red deer and roe deer showed the same alignment, even visible in the oval-shaped beds deer leave behind in snow.
The researchers tested whether the sun's position or wind direction could explain the pattern. Neither could. The alignment followed magnetic north — the direction a compass needle points — not the position of the sun in the sky. This suggested that the animals were responding to Earth's magnetic field, an invisible force field that surrounds the planet and extends through space.
A magnetic field is an invisible area of force around a magnet or around Earth itself. You can't see it, but it's there — kind of like how you can't see the wind, but you can watch it push leaves across the ground. Earth's magnetic field reaches through the air, the ground, and even through animals' bodies. A compass needle lines up with this field, and somehow, cows and deer seem to do the same thing. The field doesn't need to touch them the way a hand pushes a ball. It acts at a distance, right through empty space.
A follow-up study by Burda and colleagues in 2009 provided the most revealing clue. When cattle grazed in pastures directly beneath high-voltage power lines, their body alignment became random and disordered. Power lines generate their own extremely low-frequency magnetic fields that distort the local geomagnetic field around them. The closer the cattle stood to the lines, the more scrambled their orientation became. As distance from the power lines increased, the normal north-south alignment gradually returned.
No one touched or pushed these animals into position. Something invisible, passing through the air and ground without direct contact, was influencing which direction thousands of animals faced.