Examining a Cat's Sense of Smell & Taste

Although a cat uses it's sense of smell & taste for many uses such as a guard against predators, reproduction, and more, the primary reason a cat relies on it's sense of smell is to identify food sources and it's sense of taste is to determine if those sources are good for it.

Cat's don't just use their noses for their sense of smell, cat's have something unique at the top of their mouth called Jacobson's organs that let the cat analyze air molecules that were inhaled through the mouth and not it's nose.

You will notice your cat using this organ when she opens her mouth and seems to grimace or give some other expression that resembles disgust. This is called the "flehmen" reaction and a cat uses it to go in depth on smells it isn't sure about through it's nose. You can see this in action by just waving different things near the cat from the fridge, one of them is bound to kick in the flehmen reaction.

Cats also have scent glands on each side of the forehead, chin, lips, and on the side of the tail. They use these scent glands to mark their territory, so to speak, and that is why they often rub against you or against a piece of furniture. The cat's sense of smell is it's primary resource for identifying people and objects, not it's vision, a cat has more than 200 million odor-sensitive cells in the nose while humans only have roughly about 5 million.

A cat's sense of taste is geared towards it's food source and helps to aim at protein and fat while it eats. Cat's do not care for sweets or for salt. Cat's have a tongue that is a tool for removing feathers or fur from captured prey, the licking action is not just for taste, their tongues are covered with tiny hook-like barb called papillae. These hooks are designed for this purpose.

It is interesting to note that cats do not have that many taste buds in comparison with humans, cats have 473 while humans have over 9,000 taste buds. Cats have mushroom-shaped papillae present on the tip and at the sides of the tongue. Cats can distinguish between four tastes, sour, salty, bitter and sweet. A cat's sense of taste is really elementary compared to humans or dogs.

Sources:

The Amazing Sense of Smell, Cats International
Cat Senses, Wikipedia