Special cells help with smelling The olfactory or smell receptors are located within special sniffing cells called ethmoidal cells. These are found deep in a dog's snout in structures called turbinates. © Nevets An incredible accomplishment In one experiment, a line of 12 men followed each other, stepping in each other's footprints. After walking for a distance, each man went left or right to hide. The dog was then asked to find its owner who was the first man in the line of 12. The dog had no problem finding its owner's scent, even though it had been mixed with that of 11 other people. Smell

Dogs experience the world nose-first © Deb Smith How does a dog get the neighborhood news? Through its nose! Of all a dog's senses, its sense of smell is the most highly developed. Dogs have about 25 times more olfactory (smell) receptors than humans do. These receptors occur in special sniffing cells deep in a dog's snout and are what allow a dog to "out-smell" humans. © RONCO/Washington Dogs can sense odors at concentrations nearly 100 million times lower than humans can. They can detect one drop of blood in five quarts of water! Sniffing the bare sidewalk may seem crazy, but it yields a wealth of information to your dog, whether it's the scent of the poodle next door or a whiff of the bacon sandwich someone dropped last week. When a dog breathes normally, air doesn't pass directly over the smell receptors. But when the dog takes a deep sniff, the air travels all the way to the smell receptors, near the back of the dog's snout. So for a dog, sniffing is a big part of smelling. In the wild © Monty Sloan/Wolfpark.org Wild canines rely on smell for hunting. They also use smell to decode scent messages left by other animals -- friend or foe, predator or prey. A wild canine's sense of smell is especially important in habitats where seeing prey is difficult such as the thick underbrush of forests. Here at home: sniffing dogs © US Customs Service A dog can sniff out all sorts of smells that human noses miss. Because of this keen sense of smell, we can train them for jobs such as tracking, rescue, or drug and bomb detection and to detect a wide variety of specific scents, such as drugs, fruits or the feces of particular animals. Dogs that make a living by sniffing are trained to alert their handlers to the presence of these things by pawing, barking, or in the case of something dangerous, sitting quietly. They are trained by the promise of a favorite toy or play time each time they successfully sniff out the target scent. Can you rely on your sense of smell to solve a mystery? Put on a blindfold. Have a friend or family member hold up different types of food or spices to your nose one at a time. Can you tell what each "mystery item" is just by smelling?