Like their wild ancestors, dogs are known to howl. However, this reflects an effect of breeding, as shown by an experimental study. Dogs from “old” breeds are more likely to react to the howling of wolves with this vocalization themselves than animals that are further away from their ancestors. The more modern breeds, on the other hand, “reply” more often by barking and are less distressed by the sound of wolf howls. It is thus becoming apparent that in the course of domestication and selective breeding there has been a change in the perception and production of howls in dogs, the researchers say.
Many thousands of years ago, an amazing relationship developed across species boundaries: humans began to befriend wolves more and more intensively, until a solid partnership developed. Subsequently, humans adapted the wild form more and more to their wishes: through breeding selection, the wolf (Canis lupus) finally developed into the domestic dog (Canis familiaris). Not only did the appearance of the animals change – behavioral dispositions were also shaped by the domestication process and the development of special breeds, as studies have already made clear.
The researchers led by Fanni Lehoczki from the Eötvös Loránd University in Budapest have now dealt with a special aspect: howling. This is known to be an important communication element for wolves. They use the characteristically long-drawn-out sounds for long-distance communication with pack members and to attract attention to strangers. If a wolf hears a fellow wolf howling, in most cases it also reacts with this vocalization itself. It is clear that domestic dogs can still howl. They also seem to react instinctively to certain stimulations with these vocalizations. For example, some start howling at the sound of music or sirens. However, there appear to be individual and possibly breed-specific differences in the tendency to howl. So far, however, this has hardly been scientifically proven.
A comparison of ancient and modern breeds
As part of their study, the researchers have now examined to what extent the characteristics of a breed, as well as age and gender of dogs, influence how they react to wolf howls. 68 dogs kept in families and their caregivers took part in the tests. These were specimens from 28 different dog breeds. Based on their breeding history, the researchers assigned these breeds a degree of proximity to the wolf – a so-called “root distance” to their wild ancestors. The experiments took place in a test room in which the respective test animal was with its reference person. There the wolf howled and the researchers recorded the reaction of the animal test subjects through audio and video recordings.
As they report, they first found that there were no significant differences in howling reactions between breeds in dogs younger than five years old. According to them, this fits with indications that the tendency to howl in wolves also only develops with increasing age. In the case of the more mature animals, however, clear differences became apparent: “The animals from the older breeds were more inclined to respond to the wolf howl with their own howl. In contrast, breeds more distantly related to wolves typically responded by barking instead of howling,” reports Lehoczki. As far as other abnormalities are concerned, it became apparent: “Breeds that howl more show more behavior in this situation that reflects stress,” says Lehoczki.
Shaped by domestication and breeding
The researchers see this aspect as an indication that the wolf howl alarms these animals instinctively, which is apparently still comparatively pronounced in the older breeds. Accordingly, they may interpret what they hear, like their ancestors, as a threatening indication that a confrontation could occur. The researchers suspect that their own howling can convey the message: “Don’t come any closer!” “We assume that older breeds, which are genetically closer to wolves, can process the information encoded in wolf howls even better than modern breeds,” says senior author Tamás Faragó from Eötvös Loránd University.
As for the role of sex, the researchers found an effect on only one specific aspect: there are behavioral differences between castrated and intact males, while females do not. “Spayed individuals, thus deficient in testosterone, howled more in response to the playbacks,” says Lehoczki. Since castrated males are known to be more anxious, this seems to fit the interpretation of howling as a stress response, the researcher explains.
The bottom line is that the study results now show that in the course of domestication and selective breeding there has been a change in the perception and production of howls in dogs, the team concludes. This shows once again how complex man has shaped the characteristics of his “best friend”.
Source: Communications Biology, doi: 10.1038/s42003-023-04450-9