杏吧原创

Call it small dog syndrome. It seems when smaller dogs urinate on objects on their walks they might be using this opportunity to deceive, by aiming聽higher to give the impression that their mark was made by a much bigger聽animal.

When male dogs spray urine, they are 鈥渟cent marking鈥�: laying down an odour-based message to other dogs that communicates health, sex, and age. In this way, scent marking is considered an 鈥渉onest signal,鈥� relaying accurate information to potential competitors and mates about the聽animal鈥檚聽attributes.

But when Betty McGuire at Cornell University looked at how body size influenced scent marking, she and her team noticed a curious pattern. Small dogs urinated more frequently than larger dogs, and they were more likely to urinate towards vertically-oriented targets.

鈥淪mall males seemed to make an extra effort to raise their leg high鈥攕ome small males would almost topple over鈥�, says McGuire. 鈥淪o, we wondered whether small males try to exaggerate their body size by leaving high urine marks.鈥�

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Her team filmed adult male dogs urinating on short walks to calculate the angle of the dogs鈥� leg when raised. This was compared that to the dogs鈥� height and mass. They also measured the height of the urine marks on the chosen targets.

Unsurprisingly, when the dogs鈥� legs were raised at a higher angle, the urine hit higher on nearby surfaces. The team found that small dogs angled their legs proportionately higher when urinating than bigger dogs did, thereby marking higher than expected for their size. It鈥檚 likely the point is to deceive competing males.

鈥淒irect social interactions with other dogs may be particularly risky for small dogs,鈥� says McGuire, since they can鈥檛 measure up in physicality in one-on-one competition with bigger dogs.

This risk may be why small dogs seem to prefer scent marking, doing so more often than large dogs; it allows them to establish a presence without interacting with competitors directly.