By Victoria Schade
There’s more to canine leg lifting than meets the eye. You might think that the behavior is a uniquely male dog phenomenon that helps add his signature to every interesting vertical surface he comes across. And while many male dogs do indeed engage in a variety of elimination leg lifts, from the standard side-raise to the elaborate handstand pose, some don’t lift their leg at all when urinating. To further confuse the issue, some female dogs lift their leg as well. So what exactly is going on when dogs leg lift—or don’t leg lift—when urinating?
Leg Lifting in Male Dogs
While there are many positions that a dog may take to pee, according to Dr. Betty McGuire, a senior lecturer at Cornell University who studies scent marking in shelter dogs, there are two predominant ones for male dogs: the typical raised-leg posture with one rear leg held up, and the juvenile lean-forward posture where the dog keeps all feet on the ground. However, graduating to leg lifting is not a forgone conclusion since there is no “rite of passage” age when all male dogs begin leg lifting. In a study McGuire conducted of a beagle colony, the average age male dogs began leg lifting was at about 38 weeks. There was a great deal of variation, however, with leg lifting beginning as early as 22 weeks in some dogs and as late as 50 weeks in others.
So why don’t all mature male dogs engage in leg lifting? McGuire says there is extensive individual variation in scent-marking behavior, including urinary posture. One study with beagles found that in order for male dogs to regularly engage in leg-lifting behavior, they must have exposure to testosterone around the time of birth. McGuire suggests an interesting theory: Perhaps the variation in leg-lifting behavior in males, from extreme to nonexistent, relates to testosterone levels at birth.
Leg Lifting in Female Dogs
Much like male dogs, there are two primary urinary postures for female dogs: the squat-raise posture with one rear leg slightly raised, and the squat, which does not involve raising a rear leg. So if a female dog raises her leg when she eliminates, is she engaging in the same sort of urine-marking behavior as a male dog?
According to McGuire, lifting a leg is usually associated with directing urine at a vertical object, in both males and females. That said, there is some debate as to what constitutes regular elimination versus scent marking. Some researchers consider urination true scent marking only if the dog sniffs an object or location then eliminates on it. Many female dogs merely lift their leg a few inches when eliminating and don’t engage in the sniff-then-mark pattern, or even attempt to hit a vertical object. It’s more likely that these types of eliminations are “simple eliminations.”
McGuire found a correlation between female leg lifters and body size: small females were more likely than medium and large females to raise a rear leg. Small male dogs also follow the same pattern. “When compared with larger dogs, small dogs urinated at higher rates and directed more of their urinations at objects in the environment or locations on the ground they had previously sniffed,” McGuire says. “Our previous findings regarding urinary behavior and body size led us to suggest that small dogs preferentially communicate through urine-marking, which allows the transfer of information without direct social interaction.”
If you watch your dog as he (or she) eliminates, you might notice that your dog is what McGuire refers to as “ambilateral,” which means that he exhibits no preference as to which leg goes up when he urinates. This lack of preference might be related to having easy access to the item he wants to mark. Perhaps it’s easier for a dog to lift a left leg to mark the wall on his left and continue walking rather than stopping and reorienting himself to raise his other leg.
In a recent study, McGuire reported that dogs in high-stress situations, like those adjusting to life in a shelter, might temporarily revert to the juvenile “lean forward” elimination stance instead of leg lifting. McGuire notes that the leg-lifting behavior increased with time spent in the shelter environment, and believes that it might represent adjustment to the difficult conditions.
Some dogs add an extra signature after marking: ground scratching. This behavior, in which the dog stands near where he just eliminated and digs and kicks at the ground, provides an additional layer of “directional arrows” to the urine-marked object. If your dog lifts his leg to mark, there’s a good chance he might add a ground scratch to highlight his information as well.
Changes in Leg-Lifting
Apart from the changes in leg-lifting behaviors that are associated with reaching adulthood, it is important to take note if your dog changes the posture he or she takes when urinating. This could be a sign of pain or another medical problem that needs to be addressed. Talk to your veterinarian if you have any questions about your dog’s urinary habits.