Dog Nose.
Sensory Organs

Dog's sense of smell: Humans live in a predominately visual world, and our next most used sense is hearing but dogs live in a world made up of smells, a dog nose is therefore its most precious organ along with the tools for sounds and sights that allow it to perceive what is going on around it and make decisions based on the information it receives. Due to the close relationship that humans have with their dogs and our dog's ability to adapt so well into our world we humans often forget how important smells are to our dogs and how most of what they perceive they do through smells. Different breeds have differing degrees of olfactory sensitivity but in general all domestic dogs have a well developed olfactory sense. To live in a society predominantly based on smells, as do dogs, it is necessary to have a sense of smell that is highly superior to that of humans. Dogs of course possess an olfactory organ that allows them to not only smell much more than humans can but also to differentiate between what they smell and read and understand the messages impregnated within those smells. This of course means that dogs are not only much more aware of the smells around them but much more interested in what they smell. This highly developed sense of smell has been beneficial to humans since the relationship between dogs and humans first came into being. Dog's olfactory senses are indispensable today in the fields of police and anti-drug work. Without dog's ability to track scents with accuracy even when those scent trails pass through multitudes of conflicting scents, police investigators and detectives wouldn't have nearly as much success tracking and apprehending fugitives. Their ability to track has also been used widely and successfully when searching for lost persons in the wilderness or forest and without their help the chances of finding these lost people would have been almost nil

Dogs are also used extensively for sniffing out drugs and explosives as well as rescuing people trapped in either rubble or under snow and ice. While all dogs possess a highly developed sense of smell they must be trained to use this ability in a way that most benefits humans before they can be used in this capacity.