Vomero-Nasal Organ and the Flehmen Response
It looks like a grimace but it's actually an
MetPet.com Staff Writer
The Vomero-Nasal Organ or VMO
is also known as Jacobsen's organ. It is located in the roof
of the mouth with a small opening behind the front teeth.
This tiny organ (approximately 1/2" long) is thought to "taste"
the air and to offer the cat additional sensory information.
When a cat sniffs an odor, it sometimes draws its lips back from
its teeth into a grimace. It draws back from the source of
the odor, the eyes narrow into slits and the cat pauses to
contemplate. It may flick its tongue, sit back on its
haunches and appear to be in a trance for several seconds.
This grimace is known as the Flehmen reponse and it is the cat
making use of its VMO.
It is easy to see the grimace as a reaction
against a bad odor when it is actually just the opposite.
When a cat sniffs a sharp smelling chemical, such as those in some
household cleaners, heavily spiced foods or citrus scents, it
turns away or draws back quickly to get away from the odor.
The Flehmen response is just the opposite. The cat wants
additional information from the odor.
What is that additional information? It is
thought that female urine can produce a strong Flehmen reaction in
male cats although other odors produce it as well to differing