After their sense of site, a cat’s sense of smell is perhaps its most sensitive and important. Their small noses contain more than double the olfactory (scent) cells of a human with their much larger noses. Cat’s use their sense of smell to locate prey, to determine if something is fit to eat, to detect danger. Whilst an elderly cat’s site may fade and their hearing will dull… even an old cat will smell bacon cooking in the kitchen or a recently opened can of tuna. But as carnivores don’t expect your cat to come running at the smell of your favourite vegetarian casserole.

Cat’s also use their sense of smell to identity another cat’s territory which are marked with scent glands on the cheeks of cats. Tom cats will also use their sense of smell to detect a queen in heat.

Kittens and sense of Smell.
A kitten’s sense of smell develops early, and they learn to associate familiar smells, with safety. The smell of the mother and their den will bring a sense of security. If they are moved, the strange new smells will distress them till they are comforted by their mothers. A kitten will even be able to find its way using its sense of smell to its usual teat to feed.

Mapping out the World of Smells.
When a kitten is old enough to leave the nest and start exploring the world around it, it will map out the world around it by site, sound, but also by smell. It will associated certain areas and things by smell and in addition to noting the territories of other cats, it will commence marking its own. It does this by rubbing it head and flanks on furniture, trees, posts – even people, other pets and cats.

If you visit another house with cats and they rub against you, expect your cat to be extremely interested in the smells you bring home on your clothes, and some vigorous re marking of you to take place.

It’s difficult to fathom just how a cat ‘smells’ the world with its vastly superior sense of smell. Likely it can tell the difference between the members of your family just by their smell.

The Jacobson Organ
In addition to their superior number of olfactory cells, a cat’s sense of smell is enhanced by the vomero-nasal or Jacobson’s organ. This organ is a narrow passage which leads from the roof to the mouth to a tiny receptacle above the upper jaw which is lined with sensory smells. Upon detection of an unusual or interesting scent, a cat will open its mouth and catch the scent on its tongue where it transfers it back to the Jacobson’s organ and then on to the brain.

Dog’s with their even more sensitive sense of smell, lack this organ.

This is done via a distrinctive stance where the cat stretches is neck, opens its mouth, wrinkles and nose and pulls back its upper lip in a gesture known as flehmenng. It’s most commonly seen in toms having detected a females in heat, but it can be set off by similarly attractive smells such as catnip.