X-ray video of lapping in a dog from AW Crompton on Vimeo.
Contrary to published accounts, dogs do not scoop liquids into their mouths with a spoon-shaped cavity that forms in the ventral surface of a backwardly directed tongue tip. As in cats, an aliquot of liquid adheres to the dorsal surface of the tongue tip and is transported into the oral cavity as the tongue is rapidly withdrawn. Video-fluoroscopy recordings indicate that at least three lapping cycles are needed to transport liquid to and through the oral cavity.
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Dog lapping broth, four cycles from AW Crompton on Vimeo.
Dog lapping sequence filmed at 300fps with a Casio Exilim Pro EX-F1 [QuickPrice Check]