It’s not the size of the dog in the fight, it’s how high he can lift his leg. And if he can lift it high enough, there may not be a fight at all.

At least, that’s the hypothesis posed by authors of a new study on scent marking by male dogs. Researchers at Cornell University say smaller dogs lift their legs higher when they urinate, possibly to exaggerate their body size.

In other words, they’re lying about how big they are.

The researchers filmed and analyzed the urination patterns of 45 male shelter dogs by taking them for a walk and filming them with an iPhone—and in some cases, a high-speed camera—as they marked. Targets of opportunity included trees, benches, poles, and (of course) fire hydrants. Researchers then measured the size of the dogs, the angle at which they lifted their legs, the volume of urine they released, and which kinds of objects they were more likely to mark.

Lead author Betty Anne McGuire, PhD, senior lecturer in the Department of Ecology and Evolutionary Biology in the College of Agriculture and Life Sciences at Cornell, began studying scent-marking behavior in dogs six years ago. She started out by asking questions about how scent marking differs between males and females, or between puppies, adult, and senior dogs. Prior to the new study, McGuire and her colleagues walked nearly a thousand dogs and collected data on their height and weight.

They noticed pretty quickly that small dogs scent marked more often than large dogs. And that’s not all. “[We also] noticed that small males raised their legs up so high that they almost fell over,” McGuire told the Cornell Chronicle. “We decided at that point that it could be interesting to measure the angle of the raised leg to see if they’re trying to exaggerate their size.”

McGuire points out that scent marking is a very indirect method of communicating, because dogs can urine mark an area and then leave, thus avoiding a direct confrontation with another dog—especially a bigger dog—while still leaving olfactory evidence of having staked their claim. Marking more often and marking higher means the smaller dogs can run a bluff on any bigger dogs who come by later and fool them into thinking their potential rivals are bigger than they actually are.

Other studies have shown that dogs are certainly capable of deception.

Male dogs have also been shown to raise a leg more often during conflicts with other dogs, especially around dogs they perceive as intruders, and mark more often along territorial boundaries.

What safer way to warn off a bigger dog than to warn him off when he’s not around?

Deceptive marking to seem bigger is the canine equivalent of elevator shoes and shoulder pads.

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