In the iconic painting “His Master’s Voice (opens in new tab),” a terrier bobs his head as he listens to his owner’s voice coming from a gramophone. This gesture is one many dog owners will be familiar with, but why do dogs bob their heads?
In a 2021 study in the journal Animal knowledge (opens in new tab), researchers in Hungary conducted the first scientific study of head tilt in possums. They found that dogs can tilt their heads when they remember details that they find meaningful.
“Head tilting in dogs is a fairly well-known behavior, but the most surprising thing to me was that no one before us investigated it,” lead author of the study Andrea Sommese (opens in new tab)an ethologist (a scientist who studies natural animal behavior) at Eötvös Loránd University in Budapest, told Live Science.
In an earlier study from 2021 in the journal Scientific reports (opens in new tab), Sommese and his colleagues analyzed videos from around the world in which dog owners asked their pets to fetch them a toy by saying its name. Although 33 dogs were unable to learn the names of any new toys after three months of training, seven gifted dogs were able to learn more than 10 names during that time, with one female border collie, Whiskey, correctly identifying 54 toys.
While conducting the study, which appeared in Scientific Reports, the researchers noticed that all 40 dogs bowed their heads during the tests. The researchers then examined when the canines performed these tilts.
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In the following Animal Cognition study, the researchers found that the gifted dogs tilted their heads 43% of the time when asked to retrieve a toy by name. The other poachers tilted their heads in only 2% of these cases.
“We’re not claiming that only gifted dogs tilt their heads, while typical dogs never do,” Sommese said. “So do typical dogs, some more often than others, but in this specific situation, when the owner asks for a toy by name, only the gifted dogs show a nice inclination.”
These results suggest that canine head tilts are related to sounds that the pets have learned to find important.
“Dogs tilt their heads in a number of situations, but it appears that they only do this when they hear something that is highly relevant to them,” Sommese said. “It seems that this behavior is strongly linked to sound perception, and it could be something they do when they’re trying to listen closer, or maybe when they’re a little confused, like humans do.”
In addition, the researchers found that the side of the slope was consistent in the gifted dogs throughout the 24-month test, but the preferred side differed from dog to dog. This suggests that one side of the brain in each dog may favor the mental activity underlying head tilt, the researchers noted. Just as humans typically prefer to use one hand over the other, many dog behaviors favor one side, such as the paw with which dogs reach for an object (opens in new tab), the direction they prefer to wag their tail (opens in new tab) and even they use the nostril more when sniffing (opens in new tab)they explained.
Future research may explore what other sounds or contexts might trigger canine head tilt, he said Monique Udell (opens in new tab)a human-animal interaction researcher at Oregon State University who did not participate in the studies.
“Studies like this are important because they remind us that we, as humans, also have a lot to learn about what a dog’s body language is communicating to us,” Udell told LiveScience.com.