Why Do Dogs Lips Have Ridges?

Dog mouth with lip ridges

We all know that dogs are “man’s best friend,” but there still may be a lot you don’t know about your pal! For example, you may not know that all dogs’ lips have ridges, and you probably want to know why!

Dogs can come in all shapes and sizes, but as a species, their different breeds may have more in common than you realize.

Dogs’ lips have ridges to better grip their food and keep it in their mouths as they chew. These ridges or “bumps” also help to ensure they don’t bite on their lips while eating, as their teeth are pretty sharp and could do some serious damage. 

If you want to learn more about your dog’s lips, or any dog, keep reading! There is a lot you need to know to fully understand how a dog’s mouth works and why it is the way that it is.

Getting to know the physical body of your furry friend and why it is the way it is will help you better understand them and take better care of them!

The Anatomy of Dogs’ Lips & Mouths

Before we dig a little deeper into the ridges on your dog’s lips and why they are important, you must learn the basic anatomy of their lips and mouth! 


Dogs not only have one set of lips, they actually have two: the upper or the “flew” lips and the lower lips. These two sets of protection sit on the outside of the teeth along the jawline. 

The flew lips are the outer lips and they, along with the lower lips, protect your dog’s mouth and help the dog drink water, eat food, communicate, smell, and much more!


Dog teeth are quite different from human teeth! Not only are they larger and sharper, but there are also more of them. People have 32 teeth, while dogs have 42 baby and adult teeth. 

Dogs’ teeth are sharper because, historically, they have been used for catching and killing their food as opposed to humans, who simply use their teeth to chew. You may notice that your dog doesn’t chew its food nearly as long as you do, and it’s because their teeth aren’t made for it.


Human gums are weak, and many of us struggle with gum diseases, but dog gums are much stronger and far less likely to suffer from tooth decay. 


You may have already noticed that dogs’ tongues are extremely large compared to humans. This is because they use their tongues to not only lap up water but also to regulate their internal body temperature. 


A dog’s jawline is anatomically suited to its needs. The length and angle help them hold water in their mouths and ensure they can open their mouths wide enough to get food down their throats! 

Now that you understand why your dog’s mouth is the way it is and what these characteristics mean, we can dig a little deeper into their lips and what they do for your dog! 

How Do Dogs Use Their Lips?

Like humans, dogs use their lips for various purposes, such as drinking, eating, and communicating. But unlike humans, dogs can also use their lips to smell!

In this section, we will learn about every aspect of dogs’ lips so that you can understand the anatomy of your dog and get to know them just a little better. 

Now you know that dogs actually have two sets of lips, the upper and the lower lips. These lips both serve different functions. However, they work in conjunction to ensure your dog can do everything it needs to do to survive!


Water is essential to life. For your dog to get water into its mouth, as you can clearly see, it uses its large tongue. However, it also uses the two sets of lips to keep the water inside while it swallows. 


Dogs have large sharp teeth that are not ideal for chewing. For your dog to make its food small enough to digest, it needs to chew a few times at least, depending on the food it is eating. 

The large, two-layered lips keep the food inside the mouth while your dog prepares the food for swallowing. 

The lower lips specifically work as a shovel that moves food to the back of their throat to consume.


Just as humans frown or smile with their lips, dogs do the same! You may have already noticed that your dog often uses its lips to communicate with you, but you might not know what the signs mean. 

When a dog sticks out its lower lip, it is trying to show you it wants something from you. Now what that will depend on your dog, but no matter what, it’s important to note that it needs something!

They also use their lips to show their aggression. When they curl their upper lip back to show their teeth, it is called the “fear grin,” you will undoubtedly know that your dog either doesn’t like whoever they have met or is trying to show their dominance to another dog. 


Unlike us, dogs can even use their lips to smell! There is a channel on the roof of your dog’s mouth called the olfactory bulb from which they can smell. 

This is the best way for your dog to smell something when it’s up close!

It’s finally time to learn all about the ridges on your dog’s lips.

Why Do Dogs Lips Have Ridges

As you have learned, dogs’ lips are not just decorations! They are necessary for your dog’s survival. But why do they have ridges on them?

The general consensus from veterinarians and experts is that the ridges or serrations on a dog’s lips help keep food in the mouth while they chew and swallow and protect the lips from their sharp teeth. 

However, there are several more theories that are not believed by all experts but are popular enough to mention. 

This list of possible reasons includes the following:

  • To help grip things in the mouth. 
  • To clean their teeth. 
  • To open the mouth fully.
  • A residual part of their puppy lips. 
  • To help regulate body temperature. 

Let’s break them down!

Help With Griping

As we all know, dogs use their mouths to carry almost everything, including their own young. The ridges along the lips can arguably help during transport as they will not need to use their teeth so forcefully, therefore protecting their precious cargo. 

Cleaning Their Teeth

Some experts believe that these ridges, which naturally move up and down along a dog’s teeth, are specifically there to clean the teeth. 

It is a credible theory as, for centuries, dogs did not have humans looking after them and offering them teeth cleaning chewables or even visits to the doggy dentist!

Fully Opening the Mouth

Another reason your dog’s lips are ridged may be to help them fully open their mouths. When dogs were predators, they needed to catch their food, and in order to do so, their mouths would need to open as wide as they could. 

The ridges allow the lips to spread generously when needed, as the bumps can stretch when a dog opens its mouth widely. 

Leftover Aspect of the Puppy Body

There are certain characteristics of the body that we need as infants but grow out of as adults, and the same goes for dogs.

This theory speculates that the ridges of the lips were used to get a better grip on the mother’s nipples when breastfeeding as a puppy and that they simply don’t go away with age. 

Regulating Body Temperature

You may already know that dogs do not have sweat glands; they actually sweat through their tongue, and the tongue can grow larger when they are overheating so they can quickly cool down. 

Some veterinarians argue that the ridges of the lips can also help a dog cool down as they are made of a similar physical makeup as the tongue. 

Once again, it’s important to note that there is some disagreement among experts about why dogs have ridges on your lips, but they are certainly not short of theories!

Final Thoughts

Owning a dog is more than having a furry best friend. It’s also essential that you understand their anatomy and genetics. 

Hopefully, you now understand the various reasons dogs’ lips have ridges, including the fact that they help them keep their food in their mouths and protect their lips from their sharp teeth. 

Each of the other reasons we have listed is still in question as to their validity, but you can decide whether you think they apply to dogs in general or, more specifically, to your dog!

Similar Posts