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Why Do Cats “Blep?”

small cat with tip of tongue sticking out
boyphotos/Shutterstock

It is a truth universally acknowledged that the internet loves cats. But in recent years, the internet has grown to love a particular kind of cat seemingly more than any other kind—the blepping cat. We don’t necessarily know why cats blep, but we know we can’t get enough of it. And, honestly, it’s not hard to understand why; there are few things on this planet cuter than a blepping cat.

For the uninitiated, “blepping” describes a particular behavior in which cats are frequently known to engage: Simply letting their tongues hang out of their mouths, either in full or in part. They often don’t seem to be aware that they’re doing it; it’s like they just forgot to put their tongues away. Along with “mlem,” “blep” entered the cultural lexicon in the mid-2010s,  as an example of doggo-speak or DoggoLingo—the constantly-growing collection of internet-based slang terms, frequently onomatopoetic in nature, used to describe the various behaviors of dogs, cats, and other animals.

Although a wide variety of animals have been known to blep, cats have become particularly associated with both the word itself and the behavior it describes—which, of course, prompts the fundamental question of why they do it in the first place.

The answer, it turns out, isn’t as simple as you might think (is it ever?)—but it’s fascinating all the same. Here’s what we know about the scientific side of blepping.

Blepping and the Flehmen Response

Blepping might be connected to a specific animal behavior called the Flehmen response. The Flehmen response functions as a way for animals to gather more information about their surroundings—and, frequently, other animals that might be nearby—through two of their most highly attuned sense: taste and smell.

When an animal is exhibiting the Flehmen response, they’re opening not just their mouths, but also two ducts on the roofs of their mouths, explained anthrozoologist John Bradshaw to Slate in 2016. These ducts—the nasopalatine canals—connect to an organ called the vomeronasal organ that can process information that’s not just a taste, and not just a smell, but something’s a little bit of both. This, in turn, tells the animal a great deal about any other animals that might be coexisting in the same environment with them.

Cats are far from the only animals who exhibit the Flehmen response; it’s commonly seen in a wide variety of mammals, including horses, goats, and hedgehogs, among others. When cats display it, though, they’re typically trying to analyze a specific scent they’ve picked up in their surroundings. As certified cat behavior consultant Pam Johnson-Bennett put it to PetMD in 2018:

“It’s used primarily for analyzing pheromones from other cats, especially the ones found in urine but a cat will use it for other interesting scents that require more thorough investigation, too.”

Not all experts agree have associated then Flehmen response with blepping; for example, neither Bradshaw nor Johnson-Bennett drew that specific line in their discussion of the Flehmen response. But animal behavioral consultant Amy Shojai thinks the two things could be related. “Cats use all sense to explore the world, including taste,” Shojai told Inverse in 2018. “The Flehmen response … collects pheromones on the tongue and transfers them to the roof of the mouth to an internal ‘scent mechanism’ ([the] vomeronasal organ) to detect reproductive status or other info about other cats.” She concluded, “So ‘forgetting’ to retract the tongue in these instances might be due to fascination or distraction while deciphering these kitty ‘Post-it’ notes!”

Other Reasons for Blepping

It’s worth noting, though, that the Flehmen response more often than not involves not just an animal sticking out its tongue, but actually opening its mouth and drawing its lips back into what resembles a human-like grimace. (That’s actually where the name of the behavior comes from: It’s derived from the German word flehmen, a verb meaning to bare the upper teeth, which is itself derived from a word in Germany’s Upper Saxon dialect, flemmen, meaning “to look spiteful.”) Given the difference in appearance between a cat sticking its tongue out and a cat grimacing, there might be other explanations for what exactly is going on when a cat bleps that have nothing to do with the Flehmen response.

Certified cat behavior consultant Ingrid Johnson identified several of these explanations in an interview with Mental Floss in 2018, many of which hinge on the possibility that blepping cats don’t even really know that they’re blepping. Blepping could, for example, be a side effect of a medication the cat is on—one that “causes relaxation,” as Johnson put it. “Something for anxiety or stress or a muscle relaxer would do it.”

Heck, your cat might even blep due to feeling extremely relaxed even without medication, points out pet-centric website My Pet Needs That. “When cats are completely relaxed, they slacken their jaw, and the tip of the tongue can fall out of the front of the mouth,” the site notes—and if it happens when a cat is actually asleep, then you can take it merely as “a perfectly normal sleeping position.” Indeed, it’s “often seen at the same time as involuntary twitching” —something cats do when they’re in the dreaming phase of sleep. (Yes, cats dream.)

There might also be physiological causes for blepping. If a cat has missing teeth, a blep might occur as a result of the cat not having the necessary hardware to keep their tongue where it’s supposed to be. Said Johnson to Mental Floss, “Canine teeth help keep the tongue in place, so this would be a more common behavior for cats missing teeth, particularly on the bottom.” Some breeds also just don’t have all that much storage space in their mouths to begin with—noted Johnson, “I see [blepping] a lot with Persians because there’s just no room, to tuck [the tongue] back in.”

When Is Blepping a Concern?

Most of the time, blepping is harmless, in addition to being incredibly cute. However, if excessive blepping occurs alongside a few other symptoms, it might be worth calling your vet.

For example, drooling and having trouble eating seen with constant blepping can be indicative of oral hygiene issues or other periodontal diseases. If your cat is elderly, develops a blepping habit, and also shows signs of disorientation, house soiling, sleep cycle changes, irritability, or other symptoms, your cat may be experiencing dementia or cognitive decline. If there’s foam around your cat’s mouth while it’s blepping, it might have eaten something poisonous. Or, if it’s unusually hot out, your cat may be blepping either to cool down or as a sign of heatstroke.

But the occasional blep is likely nothing to worry about—and can provide some entertaining photo opportunities, as well. Say cheese and blep away!

Lucia Peters Lucia Peters
Lucia Peters is a writer and editor based in Washington, D.C. Her work has appeared at Bustle, The Toast, Crushable, The Gloss, and others. She also writes and manages The Ghost In My Machine, where she haunts readers several times weekly with spooky stories of the strange and unusual. Her first book, Dangerous Games To Play In The Dark, was published by Chronicle Books in September of 2019. Read Full Bio »