Why Are Dogs Such Messy Drinkers? Alexandra Harbour | Sept 13 2022
A thirsty Labrador Retriever dives into its water jug. Photo by thelabradorsite.com
Have you ever found yourself wiping up puddles around your dog’s bowl and thought, “Why? Why do dogs make such a mess while drinking water?” Apparently researchers at Virginia Tech did, because they conducted research that measured lapping in nineteen dogs of various breeds and found out why water seems to go everywhere except a dog’s mouth while it drinks.
As we all know, dogs can’t drink like humans. You won’t find a dog kicking back sipping a beverage from a chilled glass on a warm summer day (at least, I haven’t yet). This is not only because their lack of opposable thumbs prevents them from raising a glass to their lips, but also because dogs don’t have full cheeks, so they can’t create suction to drink like humans, horses and elephants can.
So how do dogs get water into their mouths? Most people think that dogs curl their tongues forward and scoop water like we scoop soup with a spoon. In fact, when a dog’s tongue plunges into a bowl of water, it actually curls backward, not forward, and the water scooped in the back of the tongue doesn’t always end up in the dog’s mouth (spoiler alert- that’s the water you clean up off your floor).
A dog’s tongue plunges into a bowl of water. Photo by | Shutterstock
It turns out that a dog’s drinking technique is way more complicated than just scooping water into its mouth. It has to do with inertial, gravitational, and surface tension forces, all of which contribute to the formation of a water column that follows the dog’s tongue up from the bowl.
The dog curls its tongue backward to increase the size of the water column, allowing it to drink more per lap than with a straight tongue.
Furthermore, when the dog pulls its tongue back into its mouth, it’s accelerating at a rate between 2 and 4 Gs- that’s faster than a rocket! Researchers found that the greater the acceleration of the dog’s tongue, the more water the dog is able to extract from the bowl.
The cycle is completed with a precisely timed bite, allowing the dog to catch the displaced water.
So yes, dogs make a mess when they drink, but they also perform an amazing feat of complicated hydrodynamics!
SOURCES:
Gart, S., Socha, J. J., Vlachos, P. P., & Jung, S. (2015). Dogs lap using acceleration-driven open pumping. Proceedings of the National Academy of Sciences, 112(52), 15798-15802. doi:10.1073/pnas.1514842112
Key, L. (2016). Biotrans 2016.
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