Smelling depends heavily on olfactory receptors, or specialised protein sensors in the nose that detect chemicals and send information to the brain.
Studies suggest cats have around 80 to 200 million olfactory receptors whereas humans have some five to six million.
Cats and humans also have a vomeronasal organ, a special patch of scent sensitive cells in the nose that lies just above the roof of the mouth. Ours barely works but in cats, this organ is well-developed.
In fact, when a cat sniffs something, curling their lip and pulling a face, they’re using their vomeronasal organ for scent analysis. Animal behaviourists call that a flehmen reaction.
In the animal world, some dogs are bred to be smelling superstars. Bloodhounds have about 300 million receptors compared to flat-faced pugs, bulldogs and boxers, that have just around 100 million.
Interestingly though, cats have an extra card in the scent game. Scientists identified protein V1R as important for distinguishing between scents. While humans have two and dogs have nine, cats have 30.
This may explain why humans and dogs have to work hard to tell the difference between one brand of tuna and another whereas cats can tell from across the room.
