Inside of a Dog_ What Dogs See, Smell, and Know - Alexandra Horowitz [41]
THE OPPOSITE OF MUTE
Her slow, light panting, mouth open partway, tongue purple and wet and perfect. Pump's panting was a conversation in and of itself—I always felt talked-to when she panted at me.
The cacophony of a packed dog run seems at first pass to be an undifferentiated racket. With closer attention, though, one can distinguish shouts from cries; yelps from barks; and play barks from threatening barks. Dogs make sounds both intentionally and inadvertently. Both kinds may hold information, the minimum requirement to call an aural disturbance a "communication" rather than simply "noise." What is interesting for scientists is determining the meaning of that information. Given the way dogs wield these noises, there is no doubt that they have different meanings.
Countless hours of researchers' lives spent listening to animals shout, coo, click, groan, and scream has led to the discovery of some universal features of sound signals. They either express something about the world—a discovery, a danger—or something about the signalers themselves—their identity, sexual status, rank, membership in a group, fear, or pleasure. They effect a change in others: they may decrease social distance between the signaler and those around him, calling someone closer; or increase social distance, frightening someone away. In addition, sounds may serve to cohere a group (in defense from a predator or intruder, for instance) or they may elicit maternal or sexual affiliation. Ultimately, all these purposes for making sounds make evolutionary sense: they aid the animal in securing its survival or the survival of its relatives.
What, then, are dogs saying, and how are they saying it? The what is answered by looking at the context of making a sound. The context includes not just the sounds around it but also the means: a screamed word winds up meaning something different than one intoned with a sultry whisper. A sound a dog makes while wagging merrily means something different than the same sound delivered through bared teeth.
The meaning of an uttered sound can also be identified by looking at what those who hear it do. Although human responses to an utterance (say, How are you?) may range from the appropriate (I'm well, thanks) to the seeming non sequitur (Yes, we have no bananas), there is reason to believe that dogs, and all non-human animals, respond ingenuously. In many cases, a sound will have a reliable effect on those in the vicinity: think Fire! or Free money!
The how of sound signaling is simple with dogs. Most of the sounds dogs make are oral: using or coming out of the mouth. At least, these are the sounds that we know about. These vocal sounds might be voiced, with vibration in the larynx—the airway used for breathing—or may be expiratory—part of an exhalation. Others are entirely unvoiced but use the mouth, such as the mechanical sound of tooth-snapping. Vocal sounds vary from one another along four easily audible dimensions. They vary in pitch (frequency): whines are nearly always high-pitched, while growls are low-pitched. Try and squeal out a growl and it becomes something else. They vary in duration: some are uttered once, quickly, lasting less than half a second; others are protracted sounds or are repeated again and again. Sounds vary in their shape: some are pure tones while others are more fractured, fluctuating or rising and falling. A howl has little variation for long periods, while barks are noisy, changeable sounds. Finally, they vary in loudness or intensity. Moans don't come in loud and yelps don't come in a whisper.
WHIMPERS, GROWLS, SQUEAKS, AND CHUCKLES
She sees I'm almost ready. With her head fixed on the ground between her paws, Pump follows me with her eyes as I cross the room gathering my bag, a book, my keys. I scratch her around her ears in consolation and break for the door. She lifts her head and makes a sound: a plaintive yelp. I freeze. A look back and she hurries over, wagging. Okay, then; I guess she'll come with me.
The paradigmatic dog sound is the bark,