He instantly went from a playful and exuberant puppy who would forget himself and gladly jump on me (down, boy!) when I came home from work to a cautious, reserved (one might even say careful) dog who would sniff me gingerly and wag his tail eagerly.
The scientific explanation, that I was emitting stress hormones or some other measurable, tangible (albeit outside our senses) pheromone makes the most sense. But I often wish that Casey could speak, even if he'd be saying "greenie, greenie, greenie" two thirds of the time.
What the Nose Knows
How well do you know your dog? The answer is, not nearly as well as your dog knows you. Given the right incentives, humans can certainly be perceptive enough. But most dog lovers discover, sooner or later, that dogs have an alertness to the behavioral signs of their owners that humans rarely equal. And that's nothing. Scientists have recently discovered that dogs can distinguish, with almost unerring accuracy, between breath samples from people with lung cancer and from people without. The dogs have to be trained to do it, of course. But the fact that they can do it at all is remarkable. There aren't enough biscuits in the world to teach a human to smell at such an extraordinary level of subtlety.
This news will give pause to almost anyone who lives with a dog. Just what a dog "knows" is hard to say, because the human idea of "knowing" is so closely related to the ability to express what you know. Even trained cancer-sniffing dogs express their knowledge - their distinction between samples - only by sitting or not sitting. But this is what always happens. We tend to forget the extraordinary powers of the animals we live with simply because we live with them. We tend to humanize them, which means, if nothing else, that we tend to reduce them - in terms of their sensory powers - to our muddling level. We can barely take in the fact that when a dog comes up and sniffs us, it is really giving us a nasal M.R.I.
Not that this will change the dynamic of our relations with man's best friend. For a while - remembering the cancer-sniffing dogs - some of us will wonder when we see our pets cock their heads, "What are you looking at?" But time will pass, and humans will be humans, and we will forget, at our end of the leash, that the beast we are walking with may already know things about us that we will discover only too late.