They possess up to 300 million olfactory receptors in their noses, compared to about six million in us. And the part of a dog's 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.
According to the researchers, the dog's sense of smell is somewhere between 10,000 to 100,000 times more acute than ours. So, no surprise, the dogs are used for following the footprints or in detecting the explosives.
