A dog is man's best friend. He can see different worlds with his nose

Vomeronasal organ lets dogs identify potential mates,or distinguish between friendly and hostile animals.It alerts them to our various emotional states,and it can even tell them when someone is pregnant or sick.Because olfaction is more primal than other senses,bypassing the thalamus to connect directly to the brain structures involving emotion and instinct,we might even say a dog's perception is more immediate and visceral than ours.But the most amazing thing about your dog's nose is that it can traverse time.The past appears in tracks left by passersby,and by the warmth of a recently parked car where the residue of where you've been and what you've done recently.Landmarks like fire hydrants and trees are aromatic bulletin boards carrying messages of who's been by,what they've been eating,and how they're feeling.And the future is in the breeze,alerting them to something or someone approaching long before you see them.Where we see and hear something at a single moment,a dog smells an entire story from start to finish.In some of the best examples of canine-human collaboration,dogs help us by sharing and reacting to those stories.They can respond with kindness to people in distress,or with aggression to threats because stress and anger manifest as a cloud of hormones recognizable to the dog's nose.With the proper training,they can even alert us to invisible threats ranging from bombs to cancer.As it turns out, humanity's best friend is not one who experiences the same things we do,but one whose incredible nose reveals a whole other world beyond our eyes.