SOME INTERESTING FACTS ABOUT CANINES
The average dog (untrained pet) has 200 to 250 million scent receptors in his/her nose.
If the membranes lining the inside of the dog's nose were laid out flat, the total surface area of those membranes would be far greater than the total surface area of the dogs entire body.
The average dog has about 7 square meters of nasal membrane - humans have about half a meter.
The average dog has such acutely sensitive scenting ability that it can detect and identify smells that are so dilute that even the most sensitive of scientific instruments cannot measure them.
Comparison - Human vs. Dog
The olfactory system is composed of the nasal chambers and the sinuses, which serve as receptor areas for scent and the olfactory nerves, which carry the signals to the olfactory lobe. It is in the brain that odors are recognized, interpreted, and filed for memory.
One big difference between man and dog is the square area of olfactory sensory cells inside the nose. It Is estimated that man has five million of these cells, while a German Sheep Dog has 220 million! A further breakdown of several breeds is as follows:
Dachshund -125 million
Fox Terrier -147 million
German Sheep Dog -220 million
The cell count appears to increase with the size of the dog. It is unfortunate that a larger variety of dogs were not examined.
Nehaus found that the dog's sensitivity to butyric acid was 100 thousand to 100 million times greater than man's.
Moulton (1969) feels that the most probable advantage conferred by increased olfactory area is the enhancement of discrimination. Even a small increment in ability will enhance the detection of subtle differences in odors.
More recent data suggests lower levels of a dog's sensitivity as being somewhere between 10 and 100 times greater than man's. There is some variability depending on the odoriferous material used and undoubtedly, the ability and motivation of the dog.