The physics of dogs drinking water

Image from Scientific American Image from Scientific American (Credit: S Gart, J Socha, Vlachos, Jung)

I have to be honest. I have always wondered whether my dog actually got any water in his mouth. It always seemed to me that the majority of water ends up on my floor. High speed video collected and analyzed by a team of researchers from Virginia Tech (Sean Gart, Jake Socha and Sunghwan Jung) and Purdue University (Pavlos Vlachos) has shown exactly how a dog is able to drink water...and also explains why they are so messy doing it. Their research was presented at the 67th Annual Meeting of the American Physics Society Division of Fluid Dynamics (November 23, 2014 — November 25, 2014).

Unlike humans, dogs do not have complete cheeks that extend around their mouths. This means they cannot create suction, which is why they drink fluids by lapping them with their tongues. This also explains why they make such a mess! Dogs curl their tongues posteriorly while literally slamming into down onto water to displace it. Displaced water gathers on the ventral surface of their tongues which is pulled into their mouths by inertia. I was surprised to learn that water gathers at a rate approximately 5 times higher than the forces associated with gravity. After withdrawing their tongues, they close their mouths very quickly to prevent the water from falling back out.

Here is a video montage put together by the researchers: Dogs drinking water in slow motion.


Scientific American

American Physics Society


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The same thing was shown for cats several years ago. I wonder how far back the mammal family tree it goes.

And all this time my daughter and I thought they just lapped it up. That was a great video.

By Groovy, Kinda (not verified) on 18 Dec 2014 #permalink

This is very interesting, I have always wondered how they managed to actually get the liquid into their mouths. I had never realized how specialized and fast the full motion was.

By Taryn Rudling … (not verified) on 10 Mar 2015 #permalink

this is really fascinating, I have always wondered how my dog is able to consume enough water by merely lapping it up. the canine body is truly remarkable I cannot wait to being to study it!

By Kimelle Krishnalall (not verified) on 03 Apr 2015 #permalink

this is a really amazing video! Dogs really are quite remarkable creatures.

By kimelle Krishnalall (not verified) on 04 Apr 2015 #permalink

I find it amazing how scientific the explanation for something as simple as the action of a dog lapping water can be. Wow.

Who would have thought that this process was so complex