What does my cat jitter his teeth?

My cat sniffs his privates and when he comes up his mouth is wide open and his teeth are jittery. His eyes are also kinda squinted. He also did this when he smelled another cats urine spot. Why does he do this?

What does my cat jitter his teeth?
Cats (along with snakes and a few other mammals) have an organ called the vomeronasal organ, most oftenly known as the Jacobson's Organ. It is located inside the mouth, just behind the front teeth, and connects to the nasal cavity. Opening his mouth slightly enables the Jacobson's Organ to open up the ducts connecting to the nasal cavity. The appearance of the cat as he brings air into the Jacobson's Organ has sometimes been likened to a "smile," other times to a grimace. The Jacobson's Organ seems to play a large part in the sense of smell of a cat.
Reply:The flehmen response brings scents into the cat's vomero-nasal organ in the roof of the mouth for additional smelling/tasting. That is the strange squinty-eyed, mouth partially open look.





The teeth chattering may allow more fluid/air into the organ to improve the scent or it may be just an excited response.