The Truth about Cats and Dogs
The first thing you might notice from this story is that multiple scientists at multiple universities study how domestic pets consume liquids. "Three years ago, we studied how cats drink," biomechanics engineer Sunny Jung explains with refreshing candor. "I was curious about how dogs drink, because cats and dogs are everywhere."
Jung, an associate professor at Virginia Tech, and his fellow researchers are presenting their findings on "How Dogs Drink Water" at the American Physical Society's fluid dynamics division meeting in San Francisco. Neither cats nor dogs can suck in liquids, since they have "incomplete cheeks" — the better to catch prey with their jaws — so they rely on gravity-defying tongue action to move liquid into their mouths.
Cats, previous research has shown, use the tip of their tongues to pull up a neat column of water, then snap their mouths to drink it. "When we started this project, we thought that dogs drink similarly to cats," Jung said in a press release. "But it turns out that it's different, because dogs smash their tongues on the water surface — they make lots of splashing — but a cat never does that." Dogs not only use a broader surface of their tongues than cats, but it turns out that bigger dogs use more of their tongues — and thus make a bigger splash and a bigger mess — than smaller dogs.
You can watch a video of a dog drinking, plus the physics behind it and impressive modeling the researchers used, below or at the researchers' presentation page. And Discovery News has video clips of a cat and dog drinking in slow motion, for comparison purposes. --Peter Weber