It's amazing what you can learn with a high-frame-rate X-ray camera, a cup of beef broth, and a Portuguese water dog. For instance, we knew that dogs are obnoxious drinkers, but we didn't realize that rather than scooping liquids into their mouths with the undersides of their tongues, they actually tap a trick of fluid mechanics--just as cats do--to pull columns of water from the water bowl into their mouths.
Thanks to evolutionary biologist Alfred Crompton and some Harvard colleagues, now we know. Crompton's study of the mechanics of canine drinking published today in the Journal of the Royal Society Biology Letters, and included are the videos seen above and, in X-ray, below. The videos and complementing study show that, contrary to conventional thought on the matter, dogs drink exactly like cats.
While dogs do pick up a certain amount of water by curling the undersides of their tongues, most of that ends up back in the bowl (or elsewhere). Rather, the flattened tongue barely nicks the surface of the water before snapping back, and when it does so it manages to pull a column of liquid into the air behind it--a column that the canine can then bite down on almost as it would a solid.
It actually takes three or four laps for the dog to work the water along its tongue and the roof of its mouth and into the throat. Which might explain why it seems like that last lap always ends up all over the floor.
That is really quite something. So essentially, the tongue hits the water and snaps back, inducing the liquid to follow it via vacuum effect?
At the risk of everyone thinking I have gone mad or am just outright lying, I will tell you of a most interesting dog that we used to have. This dog learned to drink out of large containers of water by sticking its muzzle into the water and sucking the water in, like a horse. (For those about to imply that it was a horse, save your time.)
Just wondering. Did anyone else feels that the dogs tongue did more than barely nick the surface of the water. It looks to me like it definately went in.
Sorry, they haven't convinced me at all. I see the dog clearly ladling fluid to the back of the throat while the small column that comes up with the tongue is so insignificant and mostly lost. The dog is clearly fashioning a ladle when that would be completely unnecessary if the proposed theory is correct ... simply curving the tongue backwards (but flat) would be ideal in that case (like a cat). Also the tongue goes far back into the mouth slowing down the closing of the mouth which also makes the proposed process inefficient. The mouth would have to close faster as soon as the tongue clears.
yes. amazing. mans best friends for THOUSANDS of years and we just now figure out how they drink!!!
You can clearly see that the dog is both capturing the water column AND ladling with the back of his tongue. Althouhg I wonder if the water column bit is something THIS dog or species learned to do. Lets have more x-ray dogs drinking water.
While this is informative, I just have to consider it one of those useless scientific things to know. I really have to ask, what good is knowing this? What will it bring for the future? What is the practical aspect of knowing this? Could something else better be achieved in the pursuit of science? How did they convince the dog to drink so perfectly in the glass? How many video takes did this video need? In the taking of this video, did the dog style of drinking change as he became more proficient from drink from a glass? Why is it considered typically normal as this dog drinks from a glass? How many dogs do you know that drink from a glass?
I think the video be more accurate and natural if the dog was drinking from a pond, stream or puddle. Still, in knowing how a dog tongoe laps up water, I just can't find this useful information for myself. But, hey, thank you for the info.