Saturday, September 19, 2009

St. Louis Smells

Wind's from the south today.”

When we toured the big Budweiser plant here last December we realized that the slightly sweet odor we occasionally smell in our neighborhood emanates from the brewery, a mixture of fermented grains with strong overtones of hops. The brewery is only a mile from our house. It vents massive amounts of this non-toxic gas every hour. We only smell it when the wind is from the south.

It's a good clean smell. Nobody complains. It's also a reassuring smell in a time of economic uncertainty since it means beer is still being brewed by one of St. Louis' biggest employers.

Most of the time I'm not aware of smelling anything. The scientific explanation for this is fairly simple. First, compared to other mammals, humans have a very puny nose. Second, we have evolved so that sight is our primary contact with the world. We've got eyes exquisitely well suited to interpret everything we encounter, so smelling the world takes a back seat. Third, our olfactory system stops smelling things quite quickly. Even though the chemicals for the odor are still there we forget we can smell them. The result is that human beings are not very discriminating in the olfactory department.

Because we live in a world mostly encountered by sight, we're unreliable reporters of smells. Some people are better than others at recognizing and describing what they smell. Most people typically just categorize smells as pleasant or unpleasant. To describe a specific smell we refer to common experience rather than the smell itself. Something smells like rotting fish or like a rose. Descriptions of complex specific smells are elusive. No one can describe a specific perfume, for example, without sounding hilariously vague: “violets, sugar and a hint of musk” does not conjure up anything for me.

I bring this up because of an incident this week involving our dog, Joli. First thing every morning while it's still dark I let Joli out into our yard. She's gone 2-3 minutes then comes back to eat her breakfast. On Tuesday I realized about 10 minutes had passed and she had not come back. I was concerned enough to go out to see what was up.

I saw her at the foot of the steps crouched in a typical border collie “stare.” This stance always means she has spotted something she believes is potential prey. I went down to her. In a group of flower pots overflowing with annuals was a small possum. I'd seen two in our yard before so I wasn't that surprised. Joli's nose was within a foot of the possum. The possum was cornered. It was hissing. Joli was so interested in this small animal that she growled at me to let me know how unhappy she was at being told to get inside and let the possum go on its way.

After about 15 minutes I let Joli out again to see what she would do. She immediately went to the spot where she had confronted the possum. She took a minute or two to investigate that area then set off on a complete patrol sniffing every inch of our yard and garden. She seemed sure the possum was still around. Its persistent odor told her to keep searching.

For the next two days she repeated this very complete search every morning to no avail. Only when there was no residual scent left was she finally convinced the possum was gone.

As chance would have it the Times Sunday Book Review this past week featured Inside of a Dog: What dogs see smell & know by Alexandra Horowitz, a psychology professor at Barnard College, Columbia University.

Professor Horwitz contends that we can only discover what our canine companions are thinking by trying to understand how they experience the world, their umwelt as it were. The key to understanding a dog is to realize that dogs primarily sniff the world. “As we see the world, the dog smells it. The dog's universe is a stratum of complex odors. The world of scents is at least as rich as the world of sight.”

A dog not only has a much larger area in their nose and brain devoted to smelling, they constantly renew the air in their noses so they continue to smell things long after we humans can sense no odor at all. Recent research into the mechanics of sniffing shows it to be a complex phenomena that allows a dog to exchange the air in its nostrils without inhaling or exhaling. Humans are just not very well equipped to sniff.

For me St. Louis is the strong smell of hops on a south wind; for Joli it's the subtile scent of opossum.

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