Jacobson's Organ in Cats....What it does

Humans only have about 5 to 20 million olfactory smells, where as cats have around 60 to 80 million.  The Jacobson's organ is located on the roof of a cat's mouth.  It detects and analyses pheromones (scents), especially the ones found in urine.  The scent is collected in the mouth and the cat uses its tongue to flick it up to the vomeronasal organ.  During this process, the cat will curl its upper lips in what appears to be a grimace and this is called the flehmen response, facilitating the transfer of pheromones into this vomeronasal organ.