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Why Are Dogs Such Messy Drinkers?

Dogs stay hydrated by plunging their tongue deep into water and curving it backwards into a sort of ladle shape.

A dog drinking from a water fountain

Photo: Paul Fisher (Flickr)

A dog can't learn how to be a tidy drinker.

Have you ever watched a dog drinking and are stunned by how messy the whole process is? If so, you might give your pooch more credit if you knew her lapping method is the most effective one.

A Tongue In A Ladle Shape

Dogs, like all carnivorous mammals, develop incomplete cheeks, which means they can’t form a seal for suction to drink in the way omnivorous mammals do. Dogs stay hydrated by plunging their tongue deep into water and curving it backwards into a sort of ladle shape that retracts instantly.

With all the acceleration, some of that water is sure to spill over. That’s probably what causes the mess around the bowl.

Quick Gulp

A dog’s aim isn’t really to scoop water in. What she accomplishes reaps bigger rewards.
She curves her tongue backwards to expose the maximum surface area of the front side. She curls the back facing side of the tongue to pull water upwards.

Then, the tongue quickly retracts, and the acceleration against gravity creates a suspended water column. This was her goal. The force is so great that the water sticks directly to her tongue. And she clamps her mouth shut when the water column jets in, just before it collapses.

A dog sloshes the water on purpose because it’s her way of getting a bigger gulp.

Thank you to Sean Gart of Johns Hopkins University for reviewing this episode’s script.

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