Think about the last time you saw a dog greet a long-lost friend. It’s all tongues and wetness. We usually think of licking as a "pet thing," something reserved for golden retrievers or maybe a particularly bold cat. But honestly, humans can lick too, and we do it way more often than we realize. Not just for the obvious stuff like an ice cream cone on a melting July afternoon. We use our tongues to explore the world, heal our wounds, and even communicate subtle social cues that we aren't even consciously aware of.
It’s kind of weird when you sit down and actually analyze it.
Your tongue is arguably the most flexible muscle in your body. It’s a muscular hydrostat, meaning it moves without a skeleton, much like an octopus tentacle or an elephant’s trunk. This allows for a level of precision that makes speech possible, but it also makes the act of licking a highly sophisticated biological tool.
The Science of Why Humans Can Lick Too
When we talk about licking, we’re really talking about the intersection of tactile sensation and gustatory (taste) perception. It’s not just about the flavor. It’s about the texture. Scientists at the University of Oxford have spent years studying how the "mouthfeel" of food—the physical sensation of a substance against the tongue—is often more important to our brain than the actual chemical taste.
Licking allows us to "prime" our digestive system.
When you lick something, you’re doing more than just tasting. You’re triggering a cascade of cephalic phase responses. Your brain gets a signal that food is coming. Your stomach starts producing acid. Your pancreas gets ready to release insulin. This isn't just a passive act; it's a physiological "handshake" between the external world and your internal organs.
While we don't use our tongues to groom ourselves in the way a feline does, human saliva contains histatins. These are small proteins that have been shown to speed up wound healing. You've probably noticed that a cut inside your mouth heals significantly faster than a scrape on your knee. This is why the instinctual urge to "lick your wounds" isn't just an old wives' tale—it's backed by evolutionary biology. The act of licking introduces these healing proteins to the site of an injury, though, in the modern world, we usually suggest a Band-Aid and some Neosporin instead to avoid introducing oral bacteria to an open wound.
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Beyond the Ice Cream Cone: Sensory Exploration
Kids are the masters of this.
Watch a toddler for five minutes. Everything goes in the mouth. Everything gets a lick. Why? Because the tongue and lips have a higher density of sensory neurons than almost anywhere else on the human body. For a developing brain, a lick provides a massive "data dump" of information. Is it cold? Is it porous? Is it dangerous?
As adults, we’ve mostly suppressed this. It’s "gross" to lick a countertop or a smooth stone, but the hardware is still there. We still use it for social bonding in specific contexts—think about the intimate nature of a kiss. It’s essentially a specialized, socially acceptable version of the fact that humans can lick too. It’s a way of sharing microbiome data and pheromones that help us determine biological compatibility.
The Mechanics of the Human Tongue
If you look at a tongue under a microscope, it looks like a mountain range. Those bumps? Those are papillae. Most people think those are the taste buds themselves, but that’s not quite right. The taste buds live inside the grooves of the papillae.
There are four types of papillae:
- Filiform: These don't actually have taste buds. They’re there for friction. They help you move food around.
- Fungiform: These are the mushroom-shaped ones at the front and sides.
- Foliate: These look like folds on the back edges.
- Circumvallate: The big ones at the very back.
Each of these plays a role when we engage in licking. The filiform papillae, specifically, are what give the tongue its "grip." Without them, we wouldn't be able to lick a stamp or keep a lollipop centered.
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Does it actually help with hygiene?
Probably not for us.
Unlike dogs, whose tongues act like a rough washcloth to remove dirt and loose fur, human tongues are relatively smooth. We’ve evolved to use our hands and tools for hygiene. However, the act of licking our lips is a constant, almost subconscious behavior. We do it to hydrate the thin skin of the lips, though ironically, the enzymes in saliva—like amylase—actually end up drying the lips out more in the long run. It’s a biological loop that doesn't always work in our favor.
Social Taboos and the "Ick" Factor
Why does it feel so weird to talk about the fact that humans can lick too?
Cultural conditioning.
In many Western cultures, licking is seen as primitive or unsanitary. Yet, in other contexts, it’s a sign of extreme craftsmanship. Think of a cigar aficionado licking the seam of a hand-rolled Churchill to ensure a perfect seal. Or a seamstress licking the end of a thread to help it pass through the eye of a needle. These are functional licks. They are moments where the tongue is the best tool for the job.
There’s also the psychological aspect. "Licking" is often associated with ownership. If you lick something, it's yours. No one else wants it. It’s a primal marking of territory that predates our complex laws of property.
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Health Risks: What You Should Know
It isn't all healing proteins and ice cream.
The human mouth is home to over 700 species of bacteria. Most of them are helpful or neutral, but some—like Streptococcus mutans—are the primary culprits behind tooth decay. When we lick things in the environment, we risk picking up pathogens like E. coli or various viral strains.
Furthermore, "Geographic Tongue" (benign migratory glossitis) is a condition where the tongue develops smooth, red patches that look like a map. For people with this condition, licking certain foods—especially acidic or spicy ones—can be incredibly painful. It’s a reminder that while the tongue is a powerful tool, it’s also a sensitive organ that requires its own version of "skincare."
Actionable Insights for Oral Health
Since the tongue is the primary engine behind the fact that humans can lick too, you need to take care of it. Most people brush their teeth but completely ignore the "carpet" of the mouth.
- Use a Tongue Scraper: Brushing your tongue with a toothbrush is okay, but a dedicated stainless steel or copper scraper is way more effective at removing the biofilm (that white coating) that causes bad breath.
- Stay Hydrated: A dry tongue is an ineffective tongue. Saliva is necessary for the chemical reaction of tasting and the mechanical ease of licking.
- Check for Changes: If you notice persistent white patches (leukoplakia) or sores that don't heal, stop experimenting with your sensory boundaries and see a dentist. It could be a sign of something more serious than a burnt tongue from hot coffee.
- Vary Textures: To keep your sensory processing sharp, don't just eat soft foods. Crunchy, cold, and "grippy" foods give your tongue a workout and keep the neural pathways associated with tactile oral sensation active.
The human tongue is a masterpiece of evolutionary engineering. It allows us to speak, to eat, and to experience the physical world in a way that no other limb can. So, the next time you find yourself licking a stray drop of sauce off your thumb, don't feel "animalistic." You're just using one of the most sophisticated biological tools ever created.
Next Steps for Better Oral Awareness:
- Perform a "Tongue Audit": Look in the mirror. A healthy tongue should be pink with a thin white coating. If it's bright red or heavily coated, adjust your hydration and cleaning routine.
- Experiment with "Mouthfeel": Next time you eat, focus specifically on the physical sensation against your tongue before you swallow. Notice how the different types of papillae interact with the texture.
- Sanitize Mindfully: Be aware of what you're putting in your mouth. While the instinct to explore is natural, the modern environment is full of chemicals and microbes that our ancestors didn't have to contend with.