Congrats to Sean Gart, whose research on how dogs drink was just published by PNAS. This was one of Sean's dissertation chapters. Not bad, is an understatement!
The paper can be found here, and Virginia Tech's press release can be found here.
Here's the Significance statement from the paper:
Cats and dogs are assumed to drink similarly, but little is known about the actual physical mechanisms that dogs use to transport fluids when lapping. We observed the drinking be- havior of a wide range of dogs across breeds and body size, and used physical experiments to mimic the motion of a dog’s tongue as it exits the water. Dogs accelerate the tongue up- ward more quickly than do cats, and then time their bite to coincide with the pinch-off of the column. The everyday ex- perience of dogs as messy drinkers results from the backward curl of the tongue, which increases the size of the water col- umn and thus enables dogs to drink more per lap than with a straight tongue.