Cat Purring
A cat’s purr is unique, and we are still not exactly sure how it works. It is believed that breathing in and out alternately tenses and relaxes the muscles of the larynx and diaphragm, creating pressure changes that result in turbulent airflow through the trachea. These cyclic and rapid pressure changes are superimposed on normal breathing and create the characteristic vibrations of purring. Other theories suggest that purring is a rapid contraction of muscles in the larynx and diaphragm in a constant rhythm.
Purring is instinctive. Kittens purr as early as 2 days of age. Large cats such as lions do not purr well, but cheetahs can purr.
Diseases with Hair Loss in Cats
This table lists a group of skin conditions that affect the appearance of the coat and hair. These diseases do not cause your cat much discomfort -- at least not at first. Hair loss is the main sign. It may appear as impaired growth of new hair, or you may notice a patchy loss of hair from specific areas of the body. At times, the coat does not look or feel right and may be greasy or coarse and brittle. Many of these conditions are related to hormone production. Congenital hypotrichosis:...
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A common misconception about purring is that it always indicates a state of pleasure. Sometimes it does, but cats also purr when they are hungry, stressed, or in pain. Cats have been known to purr just before dying. Some behaviorists believe purring is a signal to other cats and animals that they are not a threat.
Cat purrs are in the frequency range of 25 to 150 Hz. This frequency range is also considered to be beneficial to healing. So, perhaps cats are attempting to heal themselves at the cellular level.
WebMD Veterinary Reference from "Cat Owner's Home Veterinary Handbook"


