PH
A dog's sense of smell is dramatically more sensitive than ours.
Dogs can be trained to identify specific odor signatures associated with explosives, drugs, certain diseases, and changes in human physiology.
They also gather enormous amounts of social information simply by smelling other animals and their environment.
To humans, a room may smell like almost nothing.
To a dog, that same room can contain layers of chemical information we don't even realize are present.
© American Kennel Club