Researchers at Humboldt University, Berlin, have found that horses nod while walking to allow them to use energy more efficiently and help carry their heavy heads. The head and neck movements of eight warmbloods were recorded in walk, then a computerized movement analysis was generated. This was used to explain how the horses used energy and to predict how this energy would be used differently if they didn’t nod.
This was then compared to other studies on people swinging backpacks while walking, which showed that swinging the backpack in time with body movement causes a person to use less energy to carry it. The researchers found horses use this same technique with their heads to make their movement more energy efficient.