From The Tyee – The Secret Life of Dogs, a review of Inside of a Dog: What Dogs See, Smell and Know. Excerpt:
Even we who love dogs take them for granted. Dogs, however, study us carefully and constantly. As a result, they know us better than we know ourselves.
Alexandra Horowitz, a Barnard College psychology professor, has returned the compliment in this very readable book. Not only do we learn a lot about dogs, but we learn a lot about ourselves.
We also unlearn a lot. I'd thought dogs are colour-blind; they do see colours, mostly blues, greens, and yellows. And while sight is not as important as smell to them, they see better in many ways. We can see in a range of about 180°, but dogs have a wide-screen world of up to 270°.
They see better in the dark because light reflects off their retinas and back again, effectively doubling the signal. Dogs also see "faster" -- we process images at the rate of about 60 per second, but dogs process 70 to 80 images per second. That makes TV as boring for them as a PowerPoint presentation, but it also means they can track a Frisbee with amazing accuracy.
We also unlearn the old idea that dogs are "pack animals" trying to figure out who's the alpha in the pack. That's true for wolves, but we seem to have bred that trait out of dogs over the past 10,000 years.
You can't keep secrets from a dog's nose
Of course, it's their sense of smell that most impresses us. Horowitz says our noses have about six million receptor sites that pick up scents. Beagles have three hundred million sites. "Dogs," she says, "have more genes committed to coding olfactory cells, more cells, and more kinds of cells, able to detect more kinds of smells."
Fortunately for them, humans are highly stinky, and each of us has our own distinct scent. Even if we're freshly showered and dressed in new clothes, our dogs can identify us with a quick nose to the crotch.
Many writers about dogs are most concerned to determine how much (or how little) dogs are like us. Horowitz takes a wiser approach: She tries to get into the dog's "umwelt," its self-world, and to perceive that world as the dog does.