Why do dogs make so much noise when they lap water? To be efficient, a new study suggests.

Using photography and laboratory simulations, researchers from Virginia Tech College (Virginia Tech) studied how dogs raise fluids into their mouths to drink. They discovered that sloppy-looking actions at the dog bowl are in fact high-speed, precisely timed movements that optimize a dog's ability to acquire fluids.

Their discovery was published Dec. 14 in the Proceedings of the National Academy of Sciences.

The researchers also compared what they learned about how dogs drink with what they knew from previous studies of cats. The scientists discovered that even though feline and canine mouths structurally are similar, their approaches to drinking are as different as, well, cats and dogs.

Dogs and cats are biting animals and neither have full cheeks. But without cheeks, they can’t create suction to drink so instead, use their tongues to quickly raise water upward through a process involving inertia.

Both animals move their tongues too quickly to completely observe by the naked eye. But dogs accelerate their tongues at a much faster rate than cats, plunging them into the water and curling them downward toward their lower jaws, not their noses.

In all, 19 dogs of various sizes and breeds were volunteered for filming by their owners. The researchers measured tongue motion, recorded water volumes, and generally measured lapping in the dogs, and used the results to generate a physical model in the laboratory of the tongue’s interaction with the air-fluid interface.