We’ve all occasionally wished that our pets could speak, but their mouths, tongues and vocal cords just aren’t built for it. However, cats do sometimes use their tongues to communicate with us; they just employ a form of nonverbal communication — licking. This simple act sends a message that we, being only human, may not always understand — or appreciate.

Anyone who has ever been licked by a cat knows to expect one thing: the sudden sensation of a patch of skin being lightly sanded — over and over — by a small but astonishingly rough tongue. Sometimes while licking, a cat will even throw in a light nip or painful bite as well.

What message or sentiment is your cat trying to convey? What’s up with the biting? And why are cats’ tongues rough, anyway? Your feline pal can’t tell you — but we can.

Why Is a Cat’s Tongue Rough?

All cats — even the big ones — have abrasive tongues. What you’re feeling when a cat licks you are hundreds of spiny structures known as filiform papillae. Humans have a few different kinds of papillae on our tongues, too. You can see them (and sometimes even feel them) as tiny bumps. Papillae are where our tastebuds reside. They also contain other nerve endings that relay useful information to us, including the temperature and texture of the food we eat.

Cat Tongue Up Close

But where the most prominent forms of human papillae are mere bumps, a cat’s filiform papillae are barb-like, and made from a protein known as keratin. It’s the same stuff that cats’ claws are made of, and the hardness of the keratin (coupled with the shape of the papillae) is what gives feline tongues that distinctive sandpaper feel.

Evolution of a Cat’s Tongue

As for why cats would develop these kinds of structures on their tongues, you can blame evolution. The tiny spines aid feline predators in shredding meat and more effectively separating it from the bones of their prey. Their papillae can also aid cats in drinking, making it easier for them to pull liquid into their mouths.

Cat Grooming

Finally, that rough tongue acts as a built-in grooming tool. When a cat licks itself, those papillae make one heck of a lint brush, trapping dirt, particles and loose fur. It’s believed that this grooming capability is also an evolutionary trait: Effective grooming minimizes a cat’s odor profile, making it easier for them to sneak up on prey — and also to avoid detection from other predators.

The downside, however, is that those spiny papillae, which are slanted towards the back of a cat’s throat, move all that loose fur and detritus in a direction that leads inevitably to the formation of hairballs. Nobody said evolution was perfect. Or pretty.

Read More: 20 Things You Didn’t Know About Animal Senses

Why Does My Cat Lick Me?  

You don’t have to be an animal behavior expert to figure out some of the most obvious reasons why your cat might sidle up and start licking your head or arm or leg. On the positive side — or at least on the side that most humans want to believe — your cat may simply be expressing affection or acceptance.

Marking Their Territory

Just as their mothers groomed them as kittens, so too may they groom you because they see you as theirs: a big, awkward, mostly hairless kitten that they nevertheless consider part of the family.

Licking not only conveys that they (probably) like and trust you, but it’s also a way of claiming you, like a favorite toy. When a cat licks you, they’re not only eliminating the aroma of something else, they’re also marking you with their own scent.

A Taste of Curiosity

Of course, some cats may just want to see if you taste as interesting as you smell. Like dogs, cats have powerful olfactory senses, which they use to navigate their way in the world.

If you’ve dabbed yourself with hair gel, done a bit of gardening, made yourself a really nice sandwich, or done any of a number of other things, the scents you bring with you are likely to elicit a cat’s famous sense of curiosity. It’s only natural that they would investigate, giving you a good sniff and a lot of licks to determine just what you’ve been up to during your day.

Read More: How Long Can Cats Be Left Alone?

Is My Cat Licking Too Much?

But you can have too much of a good thing, and sometimes licking can be a problem. In general, it’s best not to let your cat lick any cuts or abrasions on your skin — they have plenty of bacteria in their mouths, and you wouldn’t want to risk infection.

Excessive licking — whether on you, themselves, another pet in the house, or even random surfaces — can be a sign of an unmet physical or emotional need. Maybe your cat is just bored and has learned that licking gets your attention, and excessive licking might just get you off the couch to play with them or provide food.

Obsessive Licking

Other times, though, obsessive licking can mean that your cat is stressed and needs to soothe itself. Or it may have a legitimate health problem: licking can be a symptom of parasitic infestation (especially fleas), environmental or food allergies, or even digestive troubles. When in doubt, consult your veterinarian.   

Why Does My Cat Lick, Then Bite?

Licking can be harmless enough, and most cat owners have learned to accept the occasional grooming session as a sign of feline love and care. But sometimes, your cat may just decide to hold its tongue and bare its teeth, suddenly taking a bite out of you or another member of the household.

Displays of Affection

If it’s just a little nip, it could easily be a sign of affection. Starting from a young age, cats are known to lick and nip each other as a form of play. Similarly, small nips or nibbling can be part of grooming and your cat could just be trying to spiff you up a little.

But if that bite is painful, causes bruising and abrasion, or actually breaks the skin, it’s a problem (especially if you have children in the house), no matter what your kitty’s intentions might be.

Signs of Stress or Overstimulation

In addition to some of the health problems mentioned above, biting after licking is commonly a sign of stress or overstimulation. If your cat licks and bites, then runs away, it may simply have had enough of you. Alternately, you may have touched them in a sensitive spot, possibly indicating an injury or an infection (especially if the ears are involved). If your cat bites you every time you touch a particular spot, it might be worth discussing with your vet.

Conversely, if you also see your cat licking and biting a favorite toy before or after licking and biting you, it may just be that they’re feeling playful and want you to join in the fun.

Read More: We’re Only Beginning To Understand Dogs’ and Cats’ Facial Expressions

How Do I Stop My Cat from Licking or Biting Me?

If there’s no underlying health problem and your cat is just annoying you with the licking and biting, you can train them to stop it. However, yelling at them, hitting them or spraying them with water are not acceptable training methods — this is only going to stress them out further and make the problem worse.

Be Gentle

Some vets recommend telling your cat “No” and moving their head gently away whenever they try to lick you too much. But most owners know this sensible technique is unlikely to work on the majority of cats, who are after all renowned for their ability to ignore verbal commands.

Distract Them

Instead, try to divert them. If excessive licking is getting on your nerves, distract them by playing with them (which is probably what they wanted all along), or giving them a toy or treat to keep them occupied.

Stay Consistent

In the case of biting, while you shouldn’t yell at your cat, when they do bite too hard, you can firmly say “No” or “Stop,” then get up and walk away. Your cat is no dummy, and, if you’re consistent in your response to the unwanted behavior, they should soon make the connection that biting too hard leads to an abrupt end to their quality time with you.

Read More: How Long Do Cats Live?