What Does a Cat's Flehmen Response Look Like?

Cat sniffing woman

Does your cat have a strange scornful expression on occasion? To scent cat pheromones, cats elevate their lips after a particularly lengthy sniff and hold their mouth slightly open. Flehmen, which is a German word that meaning "lip curl," is a totally natural and tranquil cat activity.


Pheromones, or smell hormones, are used by cats to communicate with other cats. Each animal has its own pheromones, which may communicate with other cats in different ways. To establish its territory, a cat may brush its cheek against an item and create pheromones, and pheromones in indicate their gender.

When a cat's tongue captures pheromones, it grimaces and flicks the pheromones to a duct in the roof of its mouth. This is when the so-called flehmen reaction kicks in: In what looks to be a scowl, the cat curls the top half of its lips. This second sniff-mechanism is used by all cats to assess pheromones, but male cats utilize the flehmen kitty smirk the most. That might be because, despite being neutered, they are highly sensitive to sex-related information.

Pheromones are also used by cats to mark their favorite people. A cat's headbutt or cheek rub communicates that "this person is mine." It's a genuine expression of love from your kitty partner.

Jacobson's Organs

Between the hard palate of the mouth and the septum of the nose are Jacobson's organs, also known as vomeronasal organs. Jacobson's organs are connected to the hypothalamus, which acts as a switchboard for information to be sent to other parts of the brain. They are connected to apertures in the roof of the mouth beneath kitty's teeth via tiny ducts.

Jacobson's organ is named after Danish physician Ludvig Levin Jacobson, who discovered it in 1811. Jacobson's organs are found in animals other than cats. Even humans, strangely enough, have them. Dr. Anne Marie Helmenstein claims that "While humans do not exhibit the Flehmen reaction, new research have proven that Jacobson's organ acts similarly to that of other animals in detecting pheromones and sampling tiny amounts of some non-human compounds in the air," says Dr. Helmenstein. There is evidence that Jacobson's organ is activated in pregnant women, which might explain why some women have a better during pregnancy and be linked to morning sickness.

Probably the most well-known animal with a Jacobson's organ other than cats is the common snake, which, of course, is a reptile.

Flehmen's Response

The reaction of flehmen to diverse odours may be seen in a wide range of animals. Cats and horses are the most well-known, although giraffes and elephants are also known to engage in this activity. Buffalo, goats, llamas, rhinos, pandas, and hippos have also been documented reacting to a fragrance, generally that of another animal of their species.


If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.