Inside of a Dog: What Dogs See, Smell, and Know

by Alexandra Horowitz

Urine marking is peeing with intention. The morning’s blissful release relieves the strain on the bladder, but most of the time some is held back for later use in marking. Presumably the urine is the same urine: there’s no evidence of an independent channel or means by which to modify the odor they are emitting. But marking behavior differs in a few key ways. First, in most adult males, and some gender-bending females, marking is characterized by a prominently raised leg. There are individual and contextual variations on the so-called “raised-leg display,” from a modest retraction of the rear leg up toward the body, to hoisting the leg up above the hip points, above vertical—certainly also a visual display for any other dogs in the vicinity. Both allow for a directional flow of urine, aimed to land at a conspicuous site. (One can squat and mark, too, although it is a quieter affair, perhaps for messages better whispered than shouted.) Second, the bladder is not emptied when marking; urine is doled out a little at a time, allowing for greater distribution of scent over the course of the dog’s travels. If you’ve left your dog indoors long enough that he races outside to squat, this urgency might preempt his ability to cache some urine for later marking. Thus the fruitless raised-leg displays you may witness, waving dryly at bushes, lampposts, and trash cans. Finally, dogs usually urine mark only after spending some time sniffing the area. This is what elevates the odor excha...