- Inside the cat's nose, separated by a nasal septum, is
a labyrinth of bony platelike projections called the conchae.
- The conchae nearly fill the interior of the nose.
- They are covered by an olfactory mucosa, providing a surface
of around 3-6 square inches.
- This size is twice the amount in a human's nose.
- In the mucosa are olfactory cells that detect scents.
- The olfactory cells are only at the top back of the nasal cavity,
so the scents only reach the cells if the cat is sniffing (rather
than just breathing).
- Below the nasal cavity are also curved cartilage tubes.
- These tubes are called the vomeronasal organ, or Jacobson's organ.
- These tubes connect to small holes behind the upper incisor teeth.
- This arrangement allows the cat to "taste scent" by opening its
mouth and allowing the scent to penetrate through the tubes.
- When a cat does this, it looks like it is grimacing, and it
also seems to be in a trancelike state.
- This activity is called the "Flehmen response".
- In human's the Jacobson's organ is only rudimentary, so we can't
process scent information the same way cats can.
Source: Understanding Cats -- Their History, Nature
and Behavior, by Roger Tabor, The Reader's Digest Association, Inc.,
Pleasantville, NY, 1995, pp. 64-65.