Why do cats open their mouths when they smell an odor?


If you are the proud owner of a cat, you may have already seen your feline make this strange grimace: it opens its mouth for a few seconds, sometimes even curling its lips and wrinkling its nose, suggesting a pout of disgust. The most amazing thing is that it adopts this expression only when it smells an odor. But does that mean that what it sniffs smells bad? Not so sure…


Flehmen’s answer, what is it?

If your cat occasionally opens its mouth slightly, has a puckered nose, and puckers lips, it’s because of what’s called Flehmen’s response. This word comes from German and means “to roll up the upper lip”.

Flehmen’s response is a reflex that causes your hairball to open its mouth to suck in air and allow the scent to reach Jacobson’s organ more quickly, which is located on the palate and is connected to the nasal cavity. It is this organ that will then allow them to identify the smell it smells. This is because Jacobson’s organ, or vomeronasal organ, provides more information about smells than the nasal passages. It is also thanks to this organ that cats have an overdeveloped sense of smell. It is 14 times more effective than ours, all the same!

Moreover, be aware that the cat is not the only animal to make this strange face to better sniff a smell. Horses, tigers, lions or giraffes also have this reflex.


Smells affected by Flehmen’s response

As you will have noticed, your cat does not grimace every time it sniffs an odor. In reality, the Flehmen response is primarily triggered when your feline smells pheromones, the hormones used between cats to communicate.

Each cat secretes pheromones with a very particular smell. And these pheromones contain a lot of information about the cat that produced them. Cats also use them to mark their territory since the pheromones are released when they rub against a surface, when they scratch or when they do their business. Thus, males can use Flehmen’s response to detect the presence of possible females in heat. Likewise, mothers use it to track their kittens.

So, if your cat opens its mouth, it may be to smell another cat’s urine. Or an unusual smell, especially that of a food or plant. And if it looks a little dizzy for a few seconds, it’s simply because it’s analyzing the information in the smell. In any case, there is no need to worry.


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