From Alexandra Horowitz’s “Being a Dog”

A breath is not a sniff. When someone sniffs, he is deliberately pulling in air at a rate much faster than breathing.

The length of a dog’s sniff has been measured by stuffing science gear into the dog’s nose. With this as a study limitation, a pointer holds the record for longest, most impressive sniff. He pulled in air for forty seconds while on a dead run after his prey.

To put that into context, I just inhaled vigorously while walking from the living room to the kitchen. Couldn’t crack three seconds.

She measures the intensity of your scent

If your dog is anything like mine, he is waiting for his person

(you?) at the door when that person comes home from work. Maybe your dog recognizes the distinct cough of your car’s carburetor or maybe not. It could be that he is measuring the loss of your smell in your shared space as the day goes by. When it reaches a certain point of dilution, he knows you are coming home. If my husband does not come home by the time his scent has evaporated from his bedroom, our dog moves into my office and snuggles with her favorite cat for consolation. Then she doesn’t get up until she hears him at the door. (I am not my dog’s person. Pretty sure I come after the cat.)

Canines have talent

Dogs can be trained to sniff out, not only the scent of criminals, drugs, and guns but also bedbugs, land mines, explosives, missing people, dead people, termites, and cell phones (yes, this is useful in prisons where inmates are not supposed to have them).

Dogs have been deployed to crack down on the illegal import of endangered species. They can detect a shark fin hidden in luggage. Also, tigers and turtles, black bears, and basically any animal which gives off a smell, which is one hundred percent of animals. T

hey can help you count the dead birds at a wind farm by finding every downed bird. They can also stop a dangerous invasion of non-native parasites at the airport or the freight dock. That’s right, folks. Dogs can be trained to sniff out invasive knapweed, fire ants, and tree-destroying red palm weevils.

They can smell and breathe at the same time

The slits at the side of your dog’s nose are not an arbitrary evolutionary design. They exist to allow the dog to keep breathing while holding the bouquet of an interesting smell in the main chamber.

By his urine you will know him

Your dog really is posting emails when she smells the neighborhood peeing oak and raises her leg to post a reply. Dogs are sharing information about their health, happiness, confidence level, etc.

Basically, they are telling on you and whether you are a good dog owner.

Self awareness does not require a mirror

Dogs achieve self awareness through smell, not sight. Stay with me here because this can’t be explained in a sound bite.

The traditional test for self awareness in animals is whether they recognize changes to themselves in a mirror. First you have to put a mirror in the animal’s space and let her pass it a few times.

Then you put a sticker or a mark on the animal’s face. If the animal pauses and checks out the alteration, that’s self awareness.

Elephants and dolphins are troubled by changes to their lovely demeanor, but dogs don’t give a shit how many stickers you put on their faces, they walk right by the mirror unfazed.

So it might seem that dogs are not self aware. However, in a test that measured whether a dog could differentiate the scent of its own pee from that of other dogs when isolated in vials, the dogs unerringly identified their own pee.

Then, they peed on the urine samples of other dogs and never their own. That’s self awareness.

Your own sense of smell is not gone; it’s just hiding

People can smell a small fraction of what dogs can smell. A really tiny fraction. But we haven’t lost our sense of smell, we’ve just devalued it. Through training, humans can regain some of their lost ability to navigate the world through smell. One obvious advantage that dogs have over us is a complete lack of delicacy and self consciousness. Dogs don’t hesitate to plunge their noses into a new dog’s or person’s rear end or urinary tract. They have instant access to information that our modern manners have deprived us of.