A Wilder View: How animals use Earth's magnetic field

magnetic field
Posted at 9:53 AM, Apr 06, 2023
and last updated 2023-04-06 11:53:24-04

MISSOULA - Have you ever wondered how animals don't get lost? Without GPS, they seem to find their way just fine.

Get ready to tap into your inner superhero because some animals have a hidden power. Our wildlife correspondent Tanner Saul explains why some animals have a sixth sense.

If you’re lost in the woods without a compass, you could use the positioning of the sun to determine your bearings. If it’s cloudy some species of moss tend to grow on the north side of trees, while certain lichens tend to grow on the south side. And if you’re looking at some resting or grazing deer, they may help lead the way too.

We rely heavily on our senses to tell us about our environment. But in addition to the senses of touch, smell, taste, hearing, and sight, some animals are able to sense Earth's magnetic field.

Magnetoreception may sound like something straight out of a comic book, but it's a real-life superpower that allows certain creatures to sense the Earth's magnetic field.

If you look out into a field, you may notice that most cows or deer are facing the same general direction when they feed. In the same way that birds have an instinct telling them to fly south for the winter, cows and deer tend to face north when they eat or rest.

Scientists were able to determine this over time by using field observations, measuring deer beds in snow, and mainly through satellite images by using something most of us are familiar with — Google Earth.

The reason for this is that these animals have a sort of compass in their brain. The behavior is called magnetic alignment – which is the spontaneous orientation of the main axis of an organism with respect to the field lines of the Earth's magnetic field.

Research published in the National Academy of Sciences showed that factors like wind and the angle of the sun had little significance on how the animals stood. Like needles of a compass, their heads rotated to the north.

Researchers believe that although they aren’t aware of what north means to you and me, but there is some part of their brain telling them that this is the direction they should be facing.

The first reports of magnetic alignment were found in the 1960s but it wasn’t until 2008 it was discovered mammals do this too. Besides deer and cows, it has also been researched in foxes.

Red foxes hunting small animals such as rodents show a specific behavior known as “mousing”. They listen for a mouse and approach the area slowly. Then at a certain point, it jumps high, so that it surprises its prey by falling from above — using magnetoreception to help them catch their prey!

Biologists have found foxes prefer to direct their jumps in the northeastern direction. Research has hypothesized that magnetic alignment in foxes helps the animals to estimate distances to their prey. The fox uses the earth’s magnetic field like a rangefinder you’d use for golf or hunting to accurately estimate their distance to its prey.

Foxes have what’s called radical pair-forming photopigments located in their eyes which means they may see the magnetic field as a pattern on top of what they're already seeing. Although it’s a bit of a stretch, you could compare this to Iron Man’s heads up display.

Wolves also use the earth’s magnetic field to help remember important places and territories. They seemingly use the magnetic field most similar to how we would use a compass.

They use this superpower as a way to orientate themselves based on the intensity of the magnetic field. They can also use it as a way for lost wolves to find their way back to the pack.

Another intriguing note is these animals are all as accurate as a compass. The animals don’t quite point towards the north pole, but instead, face slightly off in the direction of magnetic north. As this position, known as magnetic declination, changes across the face of the planet, so too does the direction that the wildlife in your town prefer to face.

So, you may be begging the question, can people do this too?

Across multiple studies, it’s become generally accepted that people do not sense the geomagnetic field. But new research published in Nature in 2022 found that we actually can. They could only prove it though in hungry men.

So, even though we may not have the ability to sense the magnetic field (yet!). Maybe we'll all be able to channel our inner superpower one day!