Why do dogs lick?
Medically reviewed by Dr. Bradley J. Waffa, MSPH, DVM
Why do dogs lick you? And why do dogs lick themselves? And is there ever a time you should be concerned about your dog’s licking behavior? Dogs experience the world in different ways than humans, and one way is through their tongues! We also tackle the age-old rumor… is a dog’s mouth really the cleanest in the world? The following content was originally produced as a podcast and has been transcribed below.
What is the deal with dogs and their tongues?
CJ Casselli: We are back, and we’re talking about dogs licking, which is kind of a weird topic. We’re in this public place, and we’ve watched a bunch of people go by. There have been handshakes, high fives, some people have given each other hugs. No one has licked each other yet… But dogs do. So what is the deal with dogs and their tongues?
Dr. Waffa: Yeah, right. Dogs and their tongues. What a fun question. You know, dogs just experience the world differently than people. As human beings, we are very heavily reliant on our sense of sight and our hearing. But wild canids, you know, spend some time on National Geographic, watch them move; dogs in the wild when they’re not howling at the moon or something else, they’re actually pretty quiet. They just experience the world differently. We’re sight-driven, we’re sound-driven. They are very tactile and they’re very olfactory or smell driven. Their tongue is kind of part of that. They do a lot of sensing and detecting the world with their mouths.
Why do dogs lick?
CJ Casselli: Yeah, and I think we’ve all seen that, right? Our dogs lick all sorts of stuff. I mean, my dog comes up and licks me, and people always kind of view it as a sign of affection. It’s almost like your dog is kissing you, they love you. Or in other cases, a dog is licking themselves to clean themselves. Maybe they got hurt and they’re caring for themselves in that way. So talk more about the reasons dogs lick, either us or themselves…
Dr. Waffa: Yeah. So dogs have a lot more hair than we do. Dogs groom themselves and are fairly fastidious creatures, and when they’re not arthritic, they will bend in every which way to try to clean everything. Now we have to use that word carefully. Dogs’ mouths are not clean per se. There’s a lot of bacteria.
There’s a common misconception that dogs lick their wounds and are therefore cleaning their wounds. They can actually introduce infection in that way. But they don’t like matted hair. They don’t like stuff stuck in their fur. So they will a hundred percent lick themselves just to try to keep themselves clean and tidy.
And that’s a very kind thing to do for your friend too. We consider licking an affiliative behavior in dogs. It’s one of the ways that, in human terms, they’re showing affection or saying, “Hey, you’re part of my group.” We have to be careful sometimes when we’re ascribing those types of human behaviors to dogs because they do think and experience the world differently. But the study of animal behavior and ethology would consider that an affiliative behavior…
CJ Casselli: So you almost hinted at this. What about the age-old rumor, a dog’s mouth is the cleanest thing in the world?
Dr. Waffa: Not true. Not true at all haha.
When should you see a vet?
CJ Casselli: Is there ever a reason someone should come into our clinic for their dog licking? Is there something we should encourage people to watch out for or some sort of medical concern that they should be aware of?
Dr. Waffa: It’s not commonly something that we associate with a medical problem, but certainly my first rule of thumb is if it seems odd, if it’s abnormal for your pet, you know your pet better than anyone. So listen to your gut on this.
It can absolutely be an issue. I had a very memorable case during one of my first few years in practice, where a dog was brought in because it had been obsessively licking the bricks around the fireplace. Kind of an odd presentation and blood work revealed that the animal was grossly anemic.
So we have to remember that in nature, animals will sometimes lick things like rocks to try to get salts and trace minerals. In this particular case, the dog was missing iron and magnesium from his internal blood loss. Dogs will sometimes lick their lips, and that’s a presentation we sometimes hear clients come in and describe. Lip-smacking. That can be a hallmark sign of regurgitation, which if you want to learn more about regurgitation, check out our last podcast.
But it’s not vomiting, you just get urping. And when that happens, dogs urp fluid into their mouths, and then they swallow it and then they smack their lips. And sometimes that’s the only sign until they present with aspiration pneumonia and you have a much more serious problem.
So if your dog is licking you, if your dog is licking playfully, if your dog is greeting other dogs and licking, that’s not generally a sign for concern. But any odd behavior associated with licking, for sure bring them in to have them evaluated.