Back to Blog

🐱 Understanding Cat Sneering (Flehmen Response): A Vet’s Guide 2025 🩺

  • 189 days ago
  • 7 min read

    In this article

🐱 Understanding Cat Sneering (Flehmen Response): A Vet’s Guide 2025 🩺

🐱 Understanding Cat Sneering (Flehmen Response): A Vet’s Guide 2025 🩺

By Dr. Duncan Houston, BVSc — professional veterinarian & founder of Ask A Vet 🐾

🔍 What Is the Flehmen Response?

😼 Cats often pull a funny face—curling their upper lip, raising their head, and opening their mouth—which looks like a mysterious sneer. This is known as the flehmen response 😬, and it’s a purposeful behavior that directs scent molecules straight to their vomeronasal organ (VNO) 🧠👃.

When your cat smells something intriguing—like urine, pheromones, or even your socks 🧦—they’re doing more than sniffing. They’re sampling scents to gather complex info. This response taps into an extra olfactory system beyond the average sniff. 🕵️‍♂️

🧠 How It Works: The Vomeronasal (Jacobson’s) Organ

The VNO is a specialized scent organ located on the roof of the mouth 👅. When activated, the flehmen posture lets scent particles travel into this organ via ducts behind the top teeth 🦷.

This organ analyzes chemical signals (like pheromones 💌) and relays crucial info—such as who’s around, if another cat is in heat, or if an area’s been marked. It’s your cat’s way of being a scent detective 🔎🐱.

📸 What It Looks Like: Recognizing the Sneer

  • 😼 Upper lip curled back, showing teeth and gums
  • 😮 Mouth slightly open, nostrils closed
  • 🙄 Head tilted up or neck stretched out
  • ⏳ Freeze frame moment, lasting just a few seconds

It’s not a snarl—it’s your cat “tasting” the air chemically 👅🔬.

🔍 Why Cats Do It: Common Triggers

Here’s why your cat may activate their flehmen face 😺:

  • 🚽 Smelling urine or territorial markings
  • 🐾 Investigating other cats’ grooming spots
  • 🧦 Getting curious about dirty laundry or human scents
  • 💩 Detecting strong stool or anal gland smells
  • 🌿 Sniffing catnip, toys, or new home additions

Males tend to flehmen during mating season 💘, but all cats can do it anytime something smells *interesting enough* 😸.

🌍 Flehmen Across the Animal Kingdom

Lots of animals show flehmen responses too:

  • 🦁 Big cats like lions and tigers
  • 🐴 Horses and 🐐 goats
  • 🐘 Elephants and 🦏 rhinos

Even snakes 🐍 and lizards use similar scent-sampling—but with their tongues! 👅

🚨 When It Might Be Meaningful

  • 🧼 Flehmen after urine sniffing = territorial issues?
  • 😬 Excessive flehmen with human items = possible anxiety
  • 😰 Open-mouth breathing ≠ flehmen! May signal distress

If you’re unsure, use the Ask A Vet app for instant clarity 🐾📱.

🧴 Supporting Your Cat’s Scent Exploration

  1. 🧸 Create scent-safe enrichment zones
  2. 🧼 Clean territorial spots with enzyme cleaners
  3. 📦 Let cats explore new smells slowly
  4. 🧘 Monitor and reduce stressors
  5. 🌬️ Try pheromone diffusers like Feliway

🩺 Need more help? Our expert team at Ask A Vet can guide you step-by-step 📱🐾.

🛑 Flehmen Myths Debunked

  • 🚫 It’s not about “bad smells” or disgust
  • 😼 Not a sign of aggression
  • 🙅‍♂️ Humans don’t flehmen—we lost that feature!

❓ FAQ: Quick Answers

🤔 Why does my cat flehmen when I get home?

👃 They're picking up scents from your shoes, clothes, and outside world. Totally normal!

😿 Is it ever dangerous?

Only if confused with panting or open-mouth breathing. When in doubt, call your vet 🩺.

🙃 Should I stop them?

Nope! It’s fast, harmless, and super insightful for them. 🧠

🏁 Final Thoughts from Ask A Vet

The flehmen response is a smart, quirky behavior that shows just how tuned in your cat is to their scent world 🐱🌍.

Understanding it means fewer worries—and deeper appreciation 🧡.

Need peace of mind? Chat with a vet anytime using the Ask A Vet app 📱🐾

Download the app today—because your pet deserves vet-backed support 24/7! 🩺💬

Dog Approved
Build to Last
Easy to Clean
Vet-Designed & Tested
Adventure-ready
Quality Tested & Trusted
Dog Approved
Build to Last
Easy to Clean
Vet-Designed & Tested
Adventure-ready
Quality Tested & Trusted