In this articlePreliminary ClassificationMechanism I: The Relaxation HypothesisMechanism II: The Interrupted Grooming LoopMechanism III: Sensory Processing (Advanced Consideration)Applied Blep ScienceComparative AnalysisCultural Significance: The Rise of Tongue Out TuesdayConclusionFinal RemarksView 8More +Less -By Professor Fluffovich, Feline Behavioural Scientist (Self-Appointed), Specialist in Snack Acquisition & Advanced LoungingEsteemed readers, colleagues, and providers of licky treatsIt has come to my attention, during a rigorous observational study conducted from a sun-warmed table, that a most peculiar and delightful phenomenon continues to perplex both the scientific community and the general human population.I refer, of course, to the blep.In formal scientific terminology, this behaviour would be described as transient lingual protrusion during relaxed or interrupted motor states.A phrase which, while accurate, lacks the elegant simplicity of blep.Defining the Blep (Preliminary Classification)Image provided by Kirsti HarefalletA blep may be defined as a partial, often unintended protrusion of the feline tongue, typically observed during states of relaxation, distraction, or post-grooming interruption.In laypersons terms: The cat forgot to put their tongue away.This behaviour, while outwardly whimsical, is not without a biological basis, though I acknowledge it is also deeply amusing.Mechanism I: The Relaxation HypothesisImage credit: Kirsti HarefalletWhen a cat enters a state of profound comfort (for example: post-meal, mid-sunbeam, or atop an important document), the body shifts toward what humans call a parasympathetic state.In this condition:Jaw muscles relaxFacial tension decreasesMotor control becomes shall we say optionalThe tongue, normally held in place by muscular tone, may therefore remain partially extended.Thus: Blep.Mechanism II: The Interrupted Grooming LoopFelines groom using repetitive motor sequences; efficient, elegant, and, I must add, superior to any human hygiene routine.These sequences are controlled by neural circuits often referred to as central pattern generators (CPGs), which produce rhythmic, repeated movements such as licking.However, should a cat become distracted mid-groom (by, for example, a noise, a thought, or absolutely nothing), the sequence may halt abruptly.The result?Tongue: extendedBrain: moved onSituation: unresolvedA classic case of what I term loop failure leading to blep expression.Mechanism III: Sensory Processing (Advanced Consideration)On occasion, bleps may coincide with sensory evaluation. Cats possess a specialised structure known as the vomeronasal organ (Jacobsons organ), located behind the upper incisors and involved in detecting chemical signals. While more commonly associated with the Flehmen response, subtle tongue positioning may accompany these processes.In summary: Sometimes, the blep is not a mistake.It is science at work.Applied Blep Science: The Licky Treat EffectImage Credit: Kirsti HarefalletNo scientific inquiry would be complete without experimental validation. Through repeated, highly motivated trials, I have identified a reliable method of inducing blep-like behaviour: Introduce a licky treat.These semi-liquid, highly palatable substances trigger:rapid, repetitive licking (activation of motor pattern generators)heightened focus and sensory engagementoccasional momentary pauses between licksIt is within these micro-pauses that one may observe partial tongue extension, delayed retraction, and, in optimal conditionsa transient blep-like state.It must be clarified that this is not always a true blep in the classical relaxed sense, but rather a blep-adjacent phenomenon induced by a high-value stimulus. In practical terms, the cat is too invested to manage their tongue properly.Comparative Analysis: The Canine QuestionIt is frequently asked whether dogs, too, engage in blepping. The answer is: Yes, but with notable differences. In both cats and dogs, tongue protrusion may occur during relaxed states. However, the underlying contributors differ in frequency and context.Cats:Commonly linked to relaxation and interrupted grooming motor patternsTypically presents as a small, static tongue tipDogs:May occur during relaxation, but more often associated with dental structure or missing teeth, jaw conformation, and brachycephalic anatomy (e.g., shorter muzzles)More importantly, tongue protrusion is frequently associated with thermoregulation via panting, wherein evaporative cooling occurs across the tongue and oral surfaces, a function distinct from the relaxed or interrupted motor patterns typically observed in feline blepsTongue protrusion in dogs is often more sustained and less tied to grooming behaviourIn popular culture, a distinction has emerged:Term:Typical Use:BlepSmall, subtle tongue tip (commonly cats, sometimes dogs)MlemLarger, active tongue movement (commonly in dogs)It must be emphasised that these terms are informal descriptors, not scientific classifications.Cultural Significance: The Rise of Tongue Out TuesdayIn recent years, the blep has achieved widespread recognition through the weekly observance known as #TongueOutTuesday. While I cannot confirm its precise origin, it has become a global platform for documenting and celebrating instances of lingual protrusion across species. While the weekly ritual of #TongueOutTuesday has its merits, the blep does not operate on a schedule. Perhaps it is time to elevate our standards to: Tongue Out Every Day T.O.-Day.ConclusionThe blep, while seemingly trivial, represents a fascinating intersection of neuromuscular relaxation, behavioural interruption, and sensory processing. It is, in essence, a moment where biology pauses and charm takes over.Final RemarksShould you observe a blep in your domestic environment, I advise the following:Do not panic. Do not correct the cat. Take a photograph immediately. For science, of course.With academic rigor and minimal supervision,Professor FluffovichFeline Behavioural ScientistChair of the Institute for Advanced Blep Studies