Dog Sniffing Grass
Every day, all over the world, dogs repeat the same ritual: Nose to the ground, they sniff along a dotted line of an invisible treasure map, stopping at that “X” marks the spot where they can finally get down to business.

What’s with all this sniffing, anyway? The simple answer: It’s the way dogs have been communicating with one another for centuries.

Scent Marking Is Serious Business

Scent marking is an instinctual behavior in which a dog deposits his own odor — in the form of urine or feces — onto his environment to mark territory or make a statement.

Other dogs who come upon the scent can discern a lot about fellow canines in the neighborhood. With one whiff of urine, a pup can determine how many dogs have been there, how long ago they were in the area and, best of all, if there’s a female in heat nearby.

Anal Gland Aromas

While urine marking is the most common form of scent marking, feces can also be used to leave a message. When a dog defecates, pressure against the glands on either side of the anus can cause the glands to expel a unique, musky scent onto the feces. 

Since dogs can also express their anal glands when scared, the scent may also serve to alert other dogs to danger. On a more mundane level, dogs may just sniff the feces to determine what another canine has recently eaten, telling them that ingestible goodies may be close at hand.

Once they’ve garnered all the information that they need from urine or feces, most dogs return the favor by leaving their own deposits. It’s their way of saying, “This is my turf, so stay out!”

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