- Not a substitute for professional veterinary help.
Cats interact with the world around them through their powerful sense of smell. But unlike dogs, cats don’t default to nose-to-the-ground sniffing and snuffling. Instead, sometimes, when they smell something especially interesting, they’ll draw back their lips, wrinkle their muzzles, and open their mouths into a strange sneering or grimacing expression.
Cats open their mouths to smell due to a natural and healthy reflex known as the Flehmen response, says Dr. Joanna Woodnutt, a veterinarian at Petlearnia. “[This response] is a particular way of taking in the air like sniffing, but instead of getting a scent to the detectors in the nose, it’s designed to get pheromones to the vomeronasal organ where cats can read them.”
Below, we’ll explain the Flehmen response and when cats might open their mouths, whether it’s to smell something, express emotions, or signal a medical problem.
What Is the Flehmen Response?
The Flehmen response is a normal and healthy biological response in cats. Dr. Woodnutt says that cats are solitary, so they rely on pheromones for long-distance communication. Using the Flehmen response, cats can “read” messages other cats have left behind, like if they’ve claimed a particular territory, and detect mates if they’re unspayed or unneutered.
Because it looks like a sneer or grimace, you might worry it’s a sign of aggression if you’ve never seen a cat Flehmening before.
“Although the classic Flehmen Response ‘stink face’ looks a little menacing, it’s not meant to be,” says Dr. Rebecca Greenstein, head veterinarian at Kleinburg Veterinary Hospital. She adds that it’s like tasting and sniffing a scent simultaneously.
Even kittens have a Flehmen response. They use it to absorb pheromones from their mother’s mammary glands, which helps them feel safe and calm.
Do Cats Express Emotions With Their Mouths Open?
“The Flehmen response alone doesn’t usually indicate a specific emotional state, so you’ll want to look at the rest of your cat’s body language,” says Joey Lusvardi, a certified cat behavior consultant.
Lusvardi says that cats can use an open mouth, such as baring their teeth, as a warning if they’re feeling stressed or threatened — not to be mistaken for the Flehmen response.
Awareness of the environmental context and your cat’s body language can clue you into what your cat feels. Look out for body language red flags, including:
- Lashing tail
- Flat ears
- Rippled back fur
- Vocalizations like hissing and growling
Do Cats Open Their Mouths When in Pain?
Distinguishing between normal open-mouth behavior in cats and ones that signal pain and distress is crucial for cat caregivers. Dr. Woodnutt emphasizes that while the Flehmen response is a benign biological process, persistent open-mouth breathing, like panting, calls for an immediate vet visit.
If your cat isn’t panting but is roaming around with their mouth open, it still warrants veterinary attention. Dr. Woodnutt says cats might open their mouth to soothe pain from gingivitis or another dental problem.
Symptoms that your cat is having dental or gum problems include:
- Red, swollen gums
- Bad breath
- Drooling
- Bloody saliva
- Loss of appetite
- Head shaking or holding head at an unusual angle
- Difficulty chewing and swallowing
- Pawing at mouth
- Yellow, brown, or discolored teeth
- Visibly missing or loose teeth
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Do Cats Open Their Mouths When They’re Sick?
Dr. Woodnutt says cats shouldn’t pant (unlike dogs). “Breathing with their mouth open is their body’s attempt to increase oxygen intake and is a sign of severe respiratory distress,” she explains.
While panting and labored breathing can be caused by respiratory problems, like asthma or other lung diseases, Dr. Woodnutt says heart problems are a more likely cause. Any sign of respiratory distress calls for an immediate emergency vet visit.
If you suspect your cat has a heart or respiratory problem, Dr. Woodnutt says to look out for the following symptoms:
- Lethargy
- Hiding or withdrawing
- Changes in appetite or thirst
- Changes in litterbox habits
- Coughing or wheezing
- Pale or discolored gums
- Vomiting
- Sudden weight loss
- Runny nose and sneezing
- Nasal discharge
Your vet will conduct a full physical exam and check your cat’s gum color, heart rate, and respiratory rate. Diagnostic testing and imaging, such as bloodwork, X-rays, and ultrasounds, will determine if your cat has a heart, lung, or other respiratory disease.
While they may not be able to be cured and reversed, if caught early enough, there are often medications your cat can take to manage their symptoms and slow the progression of the condition.
Takeaway
Understanding why cats open their mouths offers valuable insight into their behavior and needs. Observing your cat’s body language can provide important clues about their well-being, whether it’s a sign of exploration, communication, or a respiratory issue.
By paying attention to these subtle signals and providing appropriate care and attention, you can foster love between you and your cat while ensuring their comfort and happiness for years to come.