What Do Barking of Dogs Have in Common With Human Language?

Dogs have graced the lives of humans for approximately 10,000 years. What began with dogs cohabitating the same general areas as humans has developed into a complex social relationship in which Fido often shares his master's bed. In this bond, humans and dogs are able to influence one another's behavior through both non-vocal and vocal signals. Whether the vocalization of dogs -- notably barking -- is in fact an intentional communication strategy remains to be seen.

  1. Evolution of Domestic Dogs

    • Based on DNA analysis, domestic dogs evolved from wolflike ancestors.

      Based on DNA analysis, dogs evolved from wolf-like ancestors between 14,000 and 135,000 years ago. The process by which dogs domesticated remains uncertain. Biologist Raymond Coppinger hypothesizes that wolves essentially domesticated themselves. As humans became less nomadic and established settlements, wolves seized on an opportunity for a steady food supply and began scavenging from these settlements. Over time, they desensitized to humans and their "flight distance" -- the distance at which they would run off -- became smaller. Coppinger suggests that this tolerance for humans was bred into successive generations, and between 7,000 and 8,000 years ago, dogs were fully incorporated into human societies.

    Human Language

    • The last decade has seen intense debate about the true nature and evolution of communication in animal species, humans included. While scientists have diverging and often extreme viewpoints on the evolution of human language, all agree that animal systems of communication are both fundamentally and quantitatively different than human language. Notably, animal communication systems do not possess the richness and limitless scope of expression reflected in human language. Famed linguist Noam Chomsky defines this unique attribute as the "power of recursion" -- the ability to take a finite set of elements -- letters and words -- and yield an unlimited variety of expressions. A comparable capacity exists in no other species than human.

    Barking in Dogs

    • In Hollywood, Lassie's barking alerted Timmy to potential trouble.

      Over the years, humans have attributed barking -- a primary vocalization in dogs -- with a capacity for communication, not just between dogs, but between dogs and humans. However, the scientific research yields few certainties about the true nature of barking. In a 2002 study, University of California researcher Sophia Yin analyzed the acoustic character of barking in dogs during periods of isolation, play and disturbance. While she found that play and isolation barking were higher in frequency, shorter in duration and more tonal than disturbance barking, she could not acoustically differentiate play and isolation barking. She concluded that the acoustic structure of barks varies with context, even within individual dogs, suggesting the barks do serve specific functions.

    Mobbing

    • Domestic dogs bark more frequently than wolves.

      In her 2009 study, University of Massachusetts Amherst researcher Kathryn Lord offers another theory about the nature of barking. Analyzing eight different acoustic parameters, Lord and her team provided the scientific community with the first precise and functional definition of barking. Using these parameters, Lord argues that other animals also bark -- deer, monkeys and birds for example -- but to a far lesser extent than domestic dogs. She concludes that barking is not a system of intentional communication, but rather an auditory signal associated with a cooperative, anti-predator behavior known as "mobbing". Mobbing occurs in response to an intruder, particularly when the animal has conflicting motivations to stand its ground or flee. The mobbing call -- barking -- serves to scare off the intruder, but also vocalizes this internal conflict. She argues that domestic dogs bark far more often than other species because they are often put in situations that lead to such conflict, such as penned in cages or behind a fence.