Did you know that horses have their own GPS system? Wherever they are, horses can orientate themselves on the basis of the magnetic field around the world.
Have you ever wondered why your horse is much more forward on the way home than when you are leaving the stable? Even in an unfamiliar area riding with a loose rein your horse knows which way is home. How is this possible? Has he got a GPS built in? Horses use two types of orientation. The first one is the creation of a mental map (Type I orientation). Secondly, there’s compass orientation (Type II orientation), where animals use the magnetic field around the earth. Horses use a combination of both.
Horse have a very good memory. They remember an important location based on different beacons in the area. This is useful when you live on an open steppe and have to remember where the water is. A horse knows then for example that the water can be found at the third tree on the right and then 10 kilometers down the mountain. Using a mental map is also the most important way of navigating for humans. We display our main landmarks on a map, horses draw this map in their head and remember it.
Horses also create orientation points with the help of scents. Along the route, manure is dropped on the basis of which they can later find the way back. Other horses also use these manure piles as directions.
But even without manure horses can still find their way. It was once described that a working packhorse on the beach of Costa Rica could exactly follow the route of a stable mate who had walked home over that beach an hour earlier. The horse walked for about a kilometer with its nose 1 cm above the sand, zigzagging back and forth over the beach. As soon as he could smell his friend he changed direction, parallel to the water line in the direction of his stable 6 kilometers away. He continued to walk for about 300 meters with his nose 1 cm above the sand, after which he lifted his head to a height of 50 cm. Until another flood wave came, and he lost the scent again. At that moment he repeated his zigzag pattern with his nose to the ground, until he got back on the track again.
A mental map only works if the horse already knows the environment or if other horses have gone there before him. But what about an unknown territory? How does a horse find his way home then? Not much research has been done on this yet, but it seems that horses use the magnetic field around the earth. In a first study horses were dropped by themselves at different distances from their stable where they did not know the environment. Up to an astonishing distance of 80 km horses could easily find their way back to the stable.
In a second study, horses were dropped at locations between 15 and 25 kilometers from home. Some horses were equipped with a magnet hanging around their neck. The horses with a magnet were less able to find their way home. Horses without a magnet walked in the right direction within 15 minutes. The magnet probably disturbed the horses’ ability to orientate themselves through the magnetic field and so they got lost.
Horses are not the only animals with compass orientation. Salmon, as well as some birds and turtles, use compass orientation for their migrations.
Formation of the heard
The ultimate proof that horses can indeed feel a magnetic field came in 2009 from a researcher from Germany. Through Google Earth she discovered the standing direction of 1150 horses in 264 locations. Horses, like for example cows, reindeers and deer, were found to preferably stand in the direction of the magnetic field and not, as previously thought, in the direction of the wind or towards the sun. On average 2/3 of the animals were standing in the direction of the northern magnetic pole and 1/3 towards the southern pole. This way, the entire environment can be closely monitored by the herd.
Rein Sensors and GPS
As you can see, horses don’t need GPS and with a horse you never have to worry about losing your way home. Even so, for our own comfort and for analyzing purposes we will still equip the new sensors with GPS.
Wiltschko R. 2012 Magnetic Orientation in AnimalsJanzen D.H., 1978 How do horses find their way home?
Budiansky S., 1997 The nature of horses, Exploring Equine Evolution, Intellegence and behavior.
Hunt, 1999, Orientation and WayfindingDobel, 2012, Orientierung: Forscher entdecken magnetische Sinneszellen
Klein, 2010, Ausrichtung von Pferden unter dem Einfluss von Hochspannungsleitungen
Klein, 2010, Magnetorientierung bei Pferden
Mouritsen, 2014, Magnetoreception in Birds and Ist Use for Long-Distance Migration
Weisse, 2014, Magnetorezeption bei Säugetieren http://www.daltonmavo.nl/nask/images/antwoorden/magneetveld_aarde.gifhttp://sfk.gfz-potsdam.de/images/nsmag.jpg