Illustration by Ward Schumaker
Excerpts from “Grrr, Sniff, Arf“
A review of Alexandra Horowitz’s Inside of a Dog: What Dogs See, Smell, and Know
By CATHLEEN SCHINE
The New York Times Sunday Book Review
Published: September 8, 2009
[Horowitz’s] work draws on that of an early-20th-century German biologist, Jakob von Uexküll, who proposed that “anyone who wants to understand the life of an animal must begin by considering what he called their umvelt . . . : their subjective or ‘self-world.’ ” Hard as we may try, a dog’s-eye view is not immediately accessible to us, however, for we reside within our own umwelt, our own self-world bubble, which clouds our vision.
…Dogs, it seems, are Aristotelians, but with their own doggy teleology. Their goals are not only radically different from ours; they are often invisible to us. To get a better view, Horowitz proposes that we humans get down intellectually on all fours and start sniffing.
…To help us grasp the magnitude of the difference between the human and the canine olfactory umwelts, she details not only the physical makeup of a dog nose (a beagle nose has 300 million receptor sites, for example, compared with a human being’s six million), but also the mechanics of the canine snout. People have to exhale before we can inhale new air. Dogs do not. They breath in, then their nostrils quiver and pull the air deeper into the nose as well as out through side slits. Specialized photography reveals that the breeze generated by dog exhalation helps to pull more new scent in. In this way, dogs not only hold more scent in at once than we can, but also continuously refresh what they smell, without interruption, the way humans can keep “shifting their gaze to get another look.”
Dogs do not just detect odors better than we can. This sniffing “gaze” also gives them a very different experience of the world than our visual one gives us. One of Horowitz’s most startling insights, for me, was how even a dog’s sense of time differs from ours. For dogs, “smell tells time,” she writes. “Perspective, scale and distance are, after a fashion, in olfaction — but olfaction is fleeting. . . . Odors are less strong over time, so strength indicates newness; weakness, age. The future is smelled on the breeze that brings air from the place you’re headed.” While we mainly look at the present, the dog’s “olfactory window” onto the present is wider than our visual window, “including not just the scene currently happening, but also a snatch of the just-happened and the up-ahead. The present has a shadow of the past and a ring of the future about it.” Now that’s umwelt.
A dog’s vision affects its sense of time, too. Dogs have a higher “flicker fusion” rate than we do, which is the rate at which retinal cells can process incoming light, or “the number of snapshots of the world that the eye takes in every second.” This is one of the reasons dogs respond so well to subtle human facial reactions: “They pay attention to the slivers of time between our blinks.”) It also helps explain those eerily accurate balletic leaps after tennis balls and Frisbees, but Horowitz lets us see the implications beyond our human-centric fascination with our pets. This is more than a game of fetch; it is a profound, existential realization: “One could say that dogs see the world faster than we do, but what they really do is see just a bit more world in every second.”
As for their hearing, despite a talent for detecting those high-pitched whistles that are inaudible to us, dogs’ ability to “pinpoint where a sound is coming from is imprecise” compared with ours. Instead, their auditory sense serves to help them find the general direction of a sound, at which point their more acute sight and smell take over. As for dogs’ ability to respond to language, it has more to do with the “prosody” of our utterances than the words themselves. “High-pitched sounds mean something different than low sounds; rising sounds contrast with falling sounds,” Horowitz writes. Dogs respond to baby talk “partially because it distinguishes speech that is directed at them from the rest of the continuous yammering above their heads.”
Humans are good at seeing things right in front of us, Horowitz explains, because our photoreceptors are centrally located in an area of the retina called the fovea. Dogs do not have foveae and so are not as good at seeing things right in front of them. Those breeds, like pugs, that have retinas more like ours and can see close up, tend to be lap dogs that focus on their owners’ faces, making them seem “more companionable.” In dogs with long noses, often bred for hunting or herding, however, the photoreceptors cluster along a horizontal band spanning the middle of the eye. This is called a visual streak, and those dogs that have it “have better panoramic, high-quality vision, and much more peripheral vision than humans.”
Looks like a good one.
I’ll link some more books soon, for my fellow dog geeks.
Hat tip, MG!