Why are noses important to dogs?
The canine nose does more than smell the roses. While humans primarily depend on their vision, dogs use both sight and smell to assess their surroundings and communicate. People spend more time interpreting visual data than olfactory information. Dogs are just the opposite.
Dogs devote lots of brain power to interpreting smells. They have more than 100 million sensory receptor sites in the nasal cavity compared to 6 million in people, and the area of the canine brain devoted to analyzing odors is about 40 times larger than the comparable part of the human brain. In fact, it has been estimated that dogs can smell anywhere from 1,000 to 10,000 times better than people.
While noses do not actually speak, they do communicate. With a single sniff, noses interpret an entire story without words by using amines and acids emitted by dogs as the basis for chemical communication. The chemical aromas communicate what a dog likes to eat, and identify gender and mood. By simply smelling, a dog can determine if a new friend is male or female, happy or aggressive, healthy or ill. Dogs get a general idea about each other with a quick sniff, but get more detailed information by getting up close and personal. That is why some dogs sniff private parts of the anatomy!
Dogs also have a good scent memory that can identify other dogs they have not seen for years, and even remember which of them was the dominant member of the pair. When dogs belonging to the same family are separated for a while, they use sense of smell to catch up on things. Changes in odors may convey where the dog went, what he ate, and what he did.
When in a new territory, a dog can sniff a tree and determine what other dogs live in the neighborhood. They can smell a visitor’s pant-leg and get a good impression of where the person lives and whether he has pets at home.
Dogs also have a great homing instinct that depends on their ability to smell. Since dogs move their nostrils independently, they can determine the direction of an odor and use their sense of smell like a compass.
Humans each have a unique innate scent that enables dogs to tell one person from another. Our dogs do not need to see us to identify us. The dog’s sense of smell is so adept that a blind dog has much less difficulty adjusting to the loss of vision than a human does.
Dogs also sense fear and anxiety via their noses. When we are stressed or scared, we secrete the fight-or-flight hormone, adrenaline, which dogs detect even though we can not smell it. When we are anxious, we also have increased heart rate and blood flow which carries body chemicals to the skin surface where dogs can pick them up more easily. So, there is no use trying to mask your true feelings from your canine companion. His sense of smell will not be fooled.
When we exhale through our nose, we send the spent air out the way it came in, forcing out any incoming odors. When dogs exhale, the spent air exits through the slits in the sides of their noses. The manner in which the exhaled air swirls out actually helps usher new odors into the dogs nose. More importantly, it allows dogs to sniff more or less continuously.
We cant wiggle our nostrils independently. Dogs can. This, along with the fact that the so-called aerodynamic reach of each of their nostrils is smaller than the distance between the nostrils, helps them to determine which nostril an odor arrived in. This aids them in locating the source of smells—weve all seen dogs on an interesting scent weave back and forth across its invisible trail.
Dogs possess a sense of smell many times more sensitive than even the most advanced man-made instrument. Powerful enough to detect substances at concentrations of one part per trillion—a single drop of liquid in 20 Olympic-size swimming pools. With training, dogs can sniff out bombs and drugs, pursue suspects, and find dead bodies. And more and more, they’re being used experimentally to detect human disease—cancer, diabetes, tuberculosis, and now, malaria—from smell alone.
Dogs noses also function quite differently than our own. When we inhale, we smell and breathe through the same airways within our nose. When dogs inhale, a fold of tissue just inside their nostril helps to separate these two functions.
What do dog noses have that humans dont? They possess up to 300 million olfactory receptors in their noses, compared to about six million in us. And the part of a dogs brain that is devoted to analyzing smells is about 40 times greater than ours. Dogs also have something called neophilia, which means they are attracted to new and interesting odors.
Dogs use their smell to send messages through peeing
I love this description of dog communiques from Coren: “Dogs read about the world through their noses, and they write their messages, at least to other dogs, in their urine.” It’s tempting to drag your dog along on a walk when he’s sniffing everything annoyingly slowly, but give him chance to read the neighborhood gossip column, and let him do a little writing while he’s at it.
How do dogs “see” with their noses? – Alexandra Horowitz
It’s a well known fact that dogs have a strong sense of smell, as evidenced by the frequent stop-and-sniff sessions during those daily walks. Dogs have even been recruited to use their impeccable sense of smell to do the jobs that humans are simply incapable of, such as drug-sniffing or tracking down missing persons.
A canine’s sense of smell is so much more than simply identifying surrounding scents. In fact, scent is a dog’s primary form of communication. So, exactly how strong is your dog’s sense of smell?