Our dogs seem to spend a lot of time thinking about peeing. They put a maddening amount of thought into where to pee. Dogs often won't pee where we want them to, and they have a weird love of peeing on car tires.
Why are dogs so weird? Many papers could be written on the subject, but a recent study looks into the topic in a more specific way. The study was led by Betty McGuire, a researcher and senior lecturer at the Department of Ecology and Evolutionary Biology at Cornell University. The research asks the age-old question: Are dogs using their pee to lie about their size?
Do Small Dogs Really Pee Higher to Lie About Their Size?
Using two studies, McGuire and her team "tested the hypothesis that urine marking is a dishonest signal in adult male domestic dogs, which raise a hindlimb when marking vertical objects." In other words: Are male dogs, like so many male humans on Tinder, lying about their height?
The researchers made video recordings of adult male mixed-breed dogs (both neutered and intact) out on walks at two different animal shelters. They excluded juveniles, who are less likely to raise a leg when they pee, and seniors, who may not raise their leg because of orthopedic issues. The team used the videos to measure raised-leg angles during urination, in addition to urine-mark height (or "pee height" as animal behavior researcher and science writer Julie Hecht has dubbed it).
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The researchers found that in some cases that the urine-mark height accurately reflected the height of the urinating dog. However, this was not true of small dogs. The team found that small dogs raised their legs higher when peeing. This act increased their angles and resulted in their pee hitting higher than the dogs' actual height might predict.
Why Would Small Dogs Lie About Their Size?
While canine behavior can often seem bizarre, it usually follows some line of dog logic, no matter how odd it may seem to us humans. We don't know the exact reason that small dogs tend to raise their legs higher when urinating. However, scientists have some theories.
Julie Hecht eloquently summarizes these theories in her article for Scientific American. One theory explores the intersection of two behavioral concepts. As Hecht puts it, "dogs use pee as part of communication, and small dogs might engage in more indirect forms of communication because direct social interactions could be more costly for them." By increasing their urine-mark height, small dogs could be attempting to "exaggerate their own size," which might help avoid conflict with other dogs.
Mark My Words
Another hypothesis is that small dogs may be attempting to "over mark," meaning pee on top of other dogs' pee. Dogs of all sizes appear to over mark, but the higher a dog's urine-mark height, the more pee the urinator can pee on top of, probably causing him to feel that he or she won.
There might be a simpler explanation for all of this: It may be that bigger dogs are constrained by their size from lifting their legs higher. As you've probably observed, most dogs who lift their leg to pee lean in the opposite direction of their pee target. Larger dogs may not want to risk falling over while peeing. And who could blame them?
We're not sure yet why small dogs tend to lift their legs higher to pee. But we do know this: Dogs put a lot more thought into peeing than we do. Are we humans missing out on a whole world of interesting pee opportunities? We hope to see studies explore this topic in the near future.