A Pursuit For The Nose

It used to be that our sense of smell was a superpower, the one thing we had over animals. They could hear better or see farther and longer, but we could sniff out rotting human flesh from miles away.

Olfactory organs are located in the nose and deep inside the brain. This allows for scents to be detected before they even enter your nasal passages. Some people make a career out of sniffing things—professional noses, aromatherapists, perfume designers- but most of us never learn what our nose is capable of doing beyond smelling bad odors.

These are some of the things the human nose can do:

Read more than half of an average sized book in under 10 seconds.

Perceive an object a few inches from your face accurately, even in daylight. (This is called "binocular vision.")

Smell one ingredient in 10,000 different foods and chemicals. (Like humans, canine noses can smell up to 2000 smells.) Some dogs have been trained to detect as many as 4200 smells—the average human will not be able to detect more than about 200 smells. (Dogs' noses contain up to 2000 scent receptors and we only have about 5-10 million. There are 1200 human receptors, which means we can smell about 3x as many scents.)

Perceive the gender of a person. (This ability is more pronounced in females than in males. The average person can accurately identify the gender of up to 50 people.)

Contain a full 360 degree field of vision. Some animals have a wider field of vision than humans—alligators have some of the widest visual fields in all vertebrates (they see about 270 degrees horizontally and 170 degrees vertically), while cats' are about 80 degrees both ways and dogs' are around 100. Humans have an approximately 180-degree field of vision on either side.

Sight is not the only sense that our noses carry out, however. Many scientists believe that dogs and cats use smell to find their way home. In one famous experiment, domestic cats were released into a field and had to find their way back to the house without the use of sight or sound. When placed in different locations, they made for them home by following the scent of the owner's pet cat.

Unfortunately, no one has yet discovered what other smells dogs can detect.

What does a dog's sense of smell indicate about his personality? Does it say anything about his intelligence? Is it true that you can tell someone by smell? Are there any bio-signs that indicate health habits or mental capabilities? All of these questions might be answered with the help of a good nose.

I have been asked several times if it is true that one can tell a person by smell. I have yet to see anything written on this subject, but after having examined many hundred noses all over the world, the consensus of opinion among veterinarians and veterinarian students (both humans and animals) is that yes, you can indeed tell someone by their nose.

Many people report their dogs' sense of smell as being superior to their own. In fact, writing in Popular Science magazine about his experience with a dog named "Jazz", William Pound notes that "Jazz's nose rivals the best noses ever recorded. Even the human noses ranked as the 20th best in the world didn't come close." Pound goes on to say that when Jazz sniffed, his nostrils expanded and contracted at a rate of 70 times per second. (The human nose moves at around 30 times per second.)

While it is true that dogs have a much more acute sense of smell than humans, their olfactory capacity is still slightly less than that of humans. Pound continues to explain: "His ability doesn't mean he's necessarily more intelligent than you, just different."

Just because a dog can sniff out an amazing number of odors doesn't make him more intelligent than your average human being. Yet, it serves as a testament to the extraordinary ability of dogs' noses.

We also know that the same human trait found in dogs—a superior sense of smell—is also commonly found among humans who live in poverty- stricken countries where poor sewage and garbage disposal systems may contribute to a large number of unpleasant odors. It has also been reported that people living in areas with poor air quality often have better olfactory abilities than those who live in areas with good air quality. It is believed that these people have an increased sensitivity to odors near them because they are exposed to so many odors that would otherwise cause them discomfort and stress.

Smells are very important to dogs in many of the same ways that sounds and music are important to people. Just ask your dog! Dogs will often tell you when they smell something that is "wrong" with themselves or another animal, and if you watch closely you will be able to notice that a dog is able to discern the difference between a friend's scent and that of an enemy without ever having met the person. Dogs can also interpret different scents as "good", "bad", or even "fun".

Conclusion

While you may not be able to tell someone by their nose the same way we can, it is certainly true that humans and dogs have very similar sense of smell. Being able to enjoy the incredible talents of our noses allows us to live a rich and satisfying life. While within the dog pound, I have been asked more than once if we can tell people by their odor. In many cases, I have no doubt that dogs do!

Next week in my series on Dog Sense: The Universe of Smell, I will examine the wonderful world of animal senses.