A fluid dynamics approach to gaining understanding (adding to what’s known) of the way liquids are reliably transferred into the mouths of dogs and cats:
“Dog lapping in the matrix,” presented at the 67th Annual Meeting of the APS Division of Fluid Dynamics (November 23, 2014 — November 25, 2014), by Sean Gart (Virginia Tech) Jake Socha (Virginia Tech) Pavlos Vlachos (Purdue University), and Sunghwan Jung (Virginia Tech):
“Animals with incomplete cheeks (i.e. dogs and cats) need to move fluid against gravity into the body by means other than suction. They do this by lapping fluid with their tongue. When a dog drinks, it curls its tongue posteriorly while plunging it into the fluid and then quickly withdraws its tongue back into the mouth. During this fast retraction fluid sticks to the ventral part of the curled tongue and is drawn into the mouth due to inertia. We show examples of this drinking behavior and try to understand the relationship between tongue dynamics and geometry, lapping frequency, and dog weight. We also compare the results with a physical experiment of a rounded rod impact and withdrawal from a liquid bath.”
The researchers created a demonstrative video:
Rhodi Lee gives some additional details, in Tech Times.
(Thanks to Kerri Wachter for bringing this to our attention.)
BONUS: The 2014 Ig Nobel Prize for biology honored an ongoing attempt to determine the alignment of liquids as they transfer out the other end of dogs’ digestive systems.