What is a smell? Simply put, relatively small molecules of certain substances (molecular weight not exceeding 300) fly through the air, bind to large "receptor" molecules (at least of !000 types) of our or an animal's nasal epithelium. As surprisingly small amounts of odorous substances (sometimes a few or even a single molecule) generate the sense of smell it may be very difficult to identify their chemical nature.
Olfaction (smell)
The olfactory capabilities of cats are not well understood. Many scientists feel that cats sense of smell is not as sensitive as that of a dog. Cats do however have a very complex social structure. This leads to the belief that cats do indeed have a keen sense of smell. Cats have a complex olfactory structure which indicates that cats do indeed have a high sensitivity to smell. Odors serve an important role in the social life of cats especially in those of a solitary nature.
Cats produce odors from anal sacs, sub caudal, facial and interdigital glands. In addition, cats deposit urine and feces at prominent locations in their territories as a boundary marker to other cats. These various scents are used as a system of communication to other felids. For instance, cats will "scent-mark" heavily traveled areas where territory boundaries abut or overlap. Scents have been likened to sign post or traffic lights providing information on identity, sex, reproductive availability, and even the time when the scent was made. As an example, female cats increase their frequency of urine spraying prior to estrus. This helps attract a nearby male during the peak of the females sexual receptivity.
