Dog owners spend a great deal of time and effort training their dogs to understand humans. However, they don鈥檛 always put the same energy into learning the language of their dogs. Dogs communicate in many ways, including body language, odor, and vocalizations like barks, whines, and growls.
Barks are likely the first thing you think of when you consider dog communication. After all, they鈥檙e pretty hard to ignore. So do dogs鈥� barking sounds have meaning? According to scientists, barking is far more complex than you might realize.
Does Dog Barking Have Meaning?
Dogs bark in many situations from barking at the mail carrier to begging for scraps. Sometimes it even seems like dogs bark at nothing! That鈥檚 a far cry from how barking is used in wolves, dogs鈥� closest ancestor, where barks serve only as a defense call. How can a sound used so universally in dogs have specific meaning? Well, some scientists believe the only purpose of dog barking is attention seeking. The canine equivalent of saying, 鈥淗ey!鈥� But to other scientists, barks serve a greater use and are not a one-size-fits-all vocalization.
It鈥檚 obvious to any dog owner that their dog鈥檚 barking will sound different depending on the context. Your dog鈥檚 happy yipping when you come home is nothing like the deeper barks that warn off a delivery person encroaching on their territory. In fact, there are many ways your dog can alter their barks to potentially change their meaning or purpose. For example, a dog can vary the frequency (or pitch) of their bark, making it high and yappy or deep and low. A dog can also change the number of barks in a row and the time between barks.
Dogs Barking Sounds Change With the Situation
With so many possibilities, surely there is more going on with your dog鈥檚 barks than pure attention seeking. Indeed, that鈥檚 what research has shown. A classic study in the journal looked at how barks vary across contexts and between individual dogs. The researchers were able to categorize barks from three different scenarios 鈥� a stranger ringing the doorbell, the dog isolated from their owner, and a play session. By analyzing the barks, the researchers could measure variables like the length of the bark, the time between barks, the mean frequency or pitch, and the minimum frequency. These measurements showed statistically significant differences between the three scenarios.
For example, barks made toward the stranger ringing the doorbell were harsher and lower-pitched than barks made during play and isolation. They were also longer in duration with some barks even fusing together into what the researchers called 鈥渟uperbarks.鈥� On the other hand, play barks and isolation barks were higher pitched and tonal rather than harsh. Furthermore, isolation barks tended to occur one at a time with large gaps in between, rather than in clusters like the other two contexts.
In more general terms, the lower and harsher the bark and the shorter the inter-bark intervals, the more serious the dog. A playful dog or a lonely one will have a higher-pitched bark than a dog telling off a companion or warning an intruder. These results fit with other studies on animal communication where harsh, lower-pitched sounds are associated with hostility and higher pitched, more tonal vocalizations tend to occur during friendly interactions or when the animal is appeasing or fearful.
The study also found that barks could be identified to the individual dog regardless of context or across contexts. So, for example, although all dogs showed certain bark characteristics when isolated, the scientists could still tell different isolated dogs apart at a rate greater than chance.
Can Dogs Tell the Difference Between Barking Sounds?
Just because different barks have different properties, it doesn鈥檛 necessarily mean dogs make use of those differences or can even hear them. It may simply be a result of how aroused the dog is, rather than a deliberate communication signal. To determine if dog ears can perceive what the computer can measure, scientists need to look at dogs鈥� behavioral response to different barks.
That鈥檚 exactly what a study in the journal did. The scientists recorded barks made by Mudi in two different situations: when a stranger approached the barker鈥檚 garden and when the barker was isolated in the park. Then, they played those recordings to a separate group of dogs and measured how long the listeners oriented to the speaker playing the sounds. They determined that the dogs could distinguish between the two types of barks, as well as the different individuals barking. However, just because dogs can distinguish between different dogs鈥� barks, it doesn鈥檛 mean they recognize each other that way.
Of course, although there are differences between barks and dogs can hear those differences, it doesn鈥檛 mean the dogs are deliberately signaling different things. A study in the journal looked at barks made by hunting dogs (Dachshunds and terriers, specifically) in response to four different animal species: wild boars, rabbits, fowls, and red foxes. The researchers could classify barks based on which animal was encountered better than chance. The most distinctive barks were made toward the most dangerous animal, the wild boar. Those barks were lower and longer than those made toward the other animals. However, the researchers assumed the difference in barks was a result of the dog鈥檚 inner emotional state rather than a deliberate signal of the type of animal they had found. Still, studies such as this reinforce the belief that barks may be a complex form of communication.
Can Humans Tell the Difference Between Barking Sounds?
Dog barking may serve to communicate between dogs, but what about between dogs and people? Dogs have evolved beside humans for thousands of years and are masters at reading us. Even puppies are born ready to communicate with people. Plus, feral dogs bark less than domestic dogs. So much of the richness in bark sounds may be for our benefit.
The question is, can you use barking to better understand your dog? Research in the showed that humans, even those who don鈥檛 own dogs, are better at classifying dog barks than you might think. Prerecorded dog barks were played to human listeners, then the listeners were asked to categorize the barks. They were given a list of possible situations that could have elicited the barking and asked to choose the most appropriate one. In addition, they rated the emotion of the barking dog. The results showed that people can match the bark to the situation with accuracy far higher than chance and can identify the dog鈥檚 emotion using the pitch of the bark and the pause between barks.
To assess your own bark interpretation skills, check out the . No matter how well you fare, you can always improve your understanding of dog language by paying more attention to what dogs are telling you when they bark. And further studies, particularly those using machine learning, may tell us even more about our dog鈥檚 vocal communication.