Lift your paw to urinate is communication
Raising your paw to urinate is part of what is called stress postures in dogs, just like scratching the ground with your hind legs after defecating. This behavior is found in all canines, which also include foxes, wolves and jackals. It appears at the dog's puberty, around 6 months for a medium-sized dog, a little earlier in small dogs and later in large breed dogs.
This posture thus allows the animal to urinate voluntarily in height, generally on a vertical support (a wall, a post, a tree trunk), so that its congeners can see the visual trace more easily left by its urinary spot, which contains odorous substances charged with meaning called pheromones.
By raising his paw to pee, a dog does nothing but communicate by depositing pheromones in an obvious and visible way that his congeners are sure to come and sniff out. In addition, depositing these substances high up on a vertical support makes them more durable over time because they are less likely to be washed away by rain.
When he raises his paw, we also say that the dog is marking urine. He emits a short stream of urine that is usually not enough to empty his entire bladder. On the other hand, some dogs can eliminate all their urine by marking several times during a walk, even if nothing or almost nothing comes out of their bladder at the end of their outing! This marking behavior is also stimulated by the traces of urine left by another dog. The dog that smells them will then cover its tracks with its own urine.
Another interesting fact: the more the dog is "sure of himself" (some would say dominant), the higher he will raise his paw to score! Some dogs who do not manage their frustration well can reproduce this behavior inside the home to express their annoyance.
A behavior that does not only exist in males
While this behavior is most often observed in male dogs, it also happens that females urinate while raising their paws.
Indeed, this canine mode of communication mainly has sexual aims (but not only!), which explains why this behavior is often permanent in male dogs, sexually active all year round, and seasonal - so more rarely observed - in the non-sterilized female, during her heat which occurs once or twice a year.
By depositing sex pheromones contained in their urine, dogs thus inform their fellow dogs of their "sexual availability" .
We also know that this behavior is influenced by the dog's sex hormones and that, therefore, castration tends to reduce it.