Why Do Horses Make That Funny Face? The Flehmen Response Explained

If you’ve ever seen a horse curl their upper lip high in the air like they’re laughing at a joke only they understand, you’re not alone. It’s one of those quirky, unforgettable moments that makes you stop and go, “What on earth is going on here?”

I’ve had quite a few people ask me about it—so today, I’m answering the question:
What is that funny face horses make, and why do they do it?

Spoiler alert: it’s not just for laughs.

What Is the Flehmen Response?

That odd-looking face has a very official name: the Flehmen response (pronounced FLAY-men). It might look silly, but it’s actually serious horse business.

When a horse lifts their head, curls back their upper lip, and holds that pose for a moment, they’re not being dramatic—they’re deeply analyzing a scent. This behavior helps them draw a smell into a special organ in their mouth called the vomeronasal organ, also known as Jacobson’s organ.

You’re most likely to see it when a horse encounters a new or particularly interesting scent—more on that in a second.

Fun fact? Horses aren’t the only ones who do this. Cats, goats, and even big cats like lions and tigers all show some version of the Flehmen response!

Why Do Horses Do It?

This sniff-and-curl motion is all about collecting information.

When horses encounter certain smells—especially biological ones—they want to gather more details. The Flehmen response helps them pull that scent deeper into their mouth, where the vomeronasal organ can “read” the chemical signals.

You’ll often see the Flehmen response when a horse is sniffing:

• Urine or manure (yes, really!)

• A new foal or herd member

• A mare in heat

• Strange or unfamiliar smells in the environment

It’s how they determine friend or stranger, threat or no threat, and even hormone levels. Pretty wild, right?

So next time you catch your horse making that face, remember:
They’re not being goofy—they’re doing very important scent research. 😆

👉 Learn more about horse behavior in the Merck Veterinary Manual

When Do Horses Show This Behavior?

In my herd, I’ve seen the Flehmen response most often when a new horse arrives—or when a mare has just given birth. Dancer, being a first-time mom, was especially curious about Luna when she was a baby and spent a lot of time sniffing her and curling her lip, trying to make sense of all the new smells.

Sometimes, it happens when they explore something unusual in the pasture—or when one of them just, well… pees in an interesting spot. 😄

Is the Flehmen Response Normal?

Absolutely! The Flehmen response in horses is 100% normal and healthy. It’s just one of the many fascinating ways horses interact with the world around them.

If your horse is doing it now and then, especially around strong smells or other horses, it’s totally fine. If they start doing it constantly without an obvious reason, it’s worth mentioning to your vet—just to rule out anything unusual.

Horses Are Always Sniffing Out the Truth

That’s what I love about horses—they’re curious, sensitive, and always in tune with what’s around them. Watching their behavior is like reading a secret language, and this one just happens to look like a funny face.

So the next time you see that upper lip go flying and that nostril flare, you’ll know exactly what’s going on.

Because horses? They’re always sniffing out the truth. 🐴

🎨 Download the Flehmen Response Coloring Page!

Want a fun way to remember this silly (but science-backed) horse behavior? Download our exclusive Flehmen Response coloring page—featuring one of our real horses mid-sniff! It’s perfect for classrooms, horse-loving kids, or anyone who enjoys quirky animal facts.

📥 Download Coloring Page (PDF)

Click the download button above for the full size coloring page!