If you ever looked inside your dog's mouth while he was yawning or perhaps panting, you may have noticed several ridges on the roof of his mouth. If you have been wondering what those ridges are, consider that you're in good company; several dog owners have been wondering about those mysterious ridges too. As with most body parts in dogs, Mother Nature didn't place those ridges on the roof of the dog's mouth just for decoration; turns out, those ridges carry out several important functions.
A Lesson in Anatomy
Dogs aren't the only animals to have ridges on the top of their mouth. Humans actually have them too! If you feel the roof of your mouth with your finger or tongue, just a bit behind your front teeth, you may feel the presence of those ridges too.
Those ridges are mostly located by the front part of the roof of the mouth (hard palate) while the back part is relatively smooth and soft as it's made of tissues (soft palate). In dogs, those ridges in the mouth start just after the incisive papilla and they are quite prominent, which is possibly why they gain so much interest.
For those wondering, those ridges also have a name. They're called rugae palatinae, or more simply palatal rugae. The term rugae simply means "ridges" while palatinae simply means regarding the palate. According to the McCurnin's Clinical Textbook for Veterinary Technicians, the numbers of these rugae in dogs may vary generally ranging between 8 and 10.
Did you know? In brachycephalic dogs, these ridges are closely positioned rather than spaced out causing hair, debris and bacteria to accumulate there. (The CUSP, April 2005)
Also known as transverse palatine folds, those ridges in a dog's mouth as mentioned aren't there just for decoration; rather, they carry out some important functions.
According to a study conducted by Crompton AW and Musinsky C., when dogs drink, it's thanks to these ridges that water is prevented from falling out of the dog's mouth as the dog's tongue is protruded.
Basically, what happens is that a tight contact between the tongue's surface and the ridges helps trap the liquid ingested from the previous lapping cycle.
On top of helping a dog lap up water without spilling out, those ridges are also helpful when dogs are eating. According toM. Lynne Kesel author of Veterinary Dentistry for the Small Animal Technician those ridges apparently also aid in swallowing
"X-ray videos of dog lapping reveal the dexterity with which their tongues trap previously lapped aliquots between the rugae on the roof of their mouths and the dorsal surface of the protruding tongue, in order to access the next aliquot without losing the previously ingested one."~The Royal Society
The Importance of Fusion
Since the roof of the mouth ( palate) separates the mouth from the nasal cavities, it's important that it's nicely sealed. During infancy, the right and left sides of the dog's palate are fused together so to prevent problems.
However, in some cases, these parts may not fuse together correctly and newborn puppies present with what is called as a "cleft palate."
A cleft palate in puppies is life threatening because these puppies are not able to nurse properly and fluids can easily up into their nasal passages and airways causing aspiration pneumonia.
Did you know? The rugae of the palate are quite unique. Indeed, in humans, they can be used as a reliable guide in forensic identification when fingerprints are not available.
- McCurnin's Clinical Textbook for Veterinary Technicians, By Joanna M. Bassert, John Thomas, Saunders; 8 edition (April 19, 2013)
- How dogs lap: ingestion and intraoral transport in Canis familiaris, Biol Lett. 2011 Dec 23;7(6):882-4. doi: 10.1098/rsbl.2011.0336. Epub 2011 May 25
- ThextonA. J., McGarrickJ. D. 1988Tongue movement of the cat during lapping. Arch. Oral Biol.33, 331–339.doi:10.1016/0003-9969(88)90066-0 (doi:10.1016/0003-9969(88)90066-0)
British Veterinary Journal, Volume 61, January 1, 1905