Carlos Solis
Researchers at the University of Trento in Italy showed that the direction a dog wags its tail isn’t random. Dogs that feel comfortable tend to wag to the right from the dog’s perspective, while nervous dogs wag more to the left. Other dogs notice those differences and respond differently.
How the experiment worked
The team showed dogs video clips of other dogs on TV screens. Each clip had two versions: a natural view and a silhouette version to remove extra visual cues. While the subjects watched, the researchers measured the dogs’ behavior and their heart rates.
When the video showed a dog wagging to the right (from that dog’s perspective), the dogs watching stayed relaxed. When the wag was to the left, the observers’ heart rates rose and the dogs looked alert or anxious. In other words, the wag direction sent a social signal that other dogs could read.
Why the direction matters
The brain may look symmetrical, but many functions sit unevenly between the hemispheres. In people, for example, the left hemisphere usually handles language while the right manages spatial orientation; control of limbs crosses over, so the right hand is controlled by the left hemisphere and vice versa. That same organization exists in other animals, including dogs.
When dogs repeatedly experience one wag direction alongside friendly behavior and the other with signals they find worrying, observing dogs learn to react based on that experience.
These findings can help veterinarians, dog owners, and animal behaviorists read a dog’s emotional state more accurately and respond appropriately.
This story is based on reporting by ZME Science
