A simple walk around the block with any dog illustrates the importance of the odorous world to these animals. Whether the walk is going to be a short and brisk one or long and leisurely, the dog doesn’t care. Its entire focus is the novel odors and potential trails of chemicals that line its walk. Bits of grass, trees, sign posts, and shrubs are all must stop and smell spots for canines. Contained in these odors are a wealth of information on animals (both canine and otherwise) that have previously passed this spot. Those earlier animals have either left inadvertent signals (body odors) or intentional markings (urinary signals) that advertise the genus, sex, and health of these animals.