The old saying “The nose knows,” is especially true with your dog.

When you walk into a room the first thing you usually do is scan around with your eyes. Your dog does the same thing with his nose. Not only do dogs smell better than us, they smell differently than us as well.

The Nose Knows

Dogs can be trained to smell gunpowder or narcotics as we have seen in countless airports, border crossings, and of course movies. Bloodhounds sent in search of missing persons, can find people in earthquake rubble, and once again in those movies, they can track escaped prisoners. Though they are naturals at this smelling game, they are taught to respond to certain smells in certain ways by rewarding them in training. This is possible because they can smell better than us by a magnitude of 10,000 to 100,000 times, depending on whom you ask. James Walker, former director of the Sensory Research Institute at Florida State University says it like this, “Let’s suppose they’re just 10,000 times better,” which, of course is at the low end of the expert’s estimates, “If you make the analogy to vision, what you and I see at a third of a mile, a dog could see more than 3,000 miles away and still see as well.” At that rate, I don’t understand how our dogs stand it when I can’t even be in an elevator with someone wearing too much perfume.

Something’s Wrong

It is said and has been published in many journals that dogs can smell cancer. Cancers, especially lung and breast cancers supposedly have a certain smell that even some humans can detect through the patient’s breath. Though humans may be able to smell cancer on the breath during the latter stages (Stage 3 or 4) dogs, on the other hand, can smell it in early stages 0, 1 or 2. Dogs can smell things in parts per trillion so if humans can detect anything at all; your dog already knew it was there.

Oh, How Sweet

Dogs can be trained to smell diabetes on humans. They can be trained to detect when your blood sugar levels have dropped drastically. A woman named Clair Moon, afflicted with what’s called Brittle diabetes, has claimed her dog named Magic has detected her drop in blood sugar over 800 times This is especially impressive because Blair’s affliction can cause her to slip into a coma.

How Do They Do That?

Dogs have a fold of tissue just inside their nose that helps to make all this possible. The fold spits up the smell from the breathing as explained by Brent Craven, a Bioengineer at Pennsylvania State University. “We found that when airflow enters the nose it splits into two different flow paths, one for olfaction and one for respiration.” They also excel when exhaling. When we exhale we are also forcing air and conversely smells out or away. Dogs, on the other hand, exhale through the slits in the side of their noses. The way the dog exhales swirls the air and actually helps send in new odors. In other words they can basically sniff continuously. A study done at the University of Oslo in Norway concluded that a hunting dog holding his head into the wind sniffed in a continuous stream of air for 40 seconds.

Oh Baby

When it comes to sniffing your crotch (and other dogs' butts), dogs are just gathering information about you, maybe more than you are comfortable with. When they do it to another dog they are determining the dog’s sex, stress levels, hormones or even how hostile this dog may be. Dogs can also smell pheromones which helps them spot females in ovulation. Experiments have been done in which dogs selected cows that were ovulating to help ranchers in Australia with their breeding programs.