Ever wonder why cats purr and what it means? Recently I have, so I decided to investigate. The first thing I found out was that scientists still aren’t sure how cats actually do it. There is no unique anatomic feature that explains it so a number of theories have been bandied about.
One theory is that nerves are activated in the voice box and that those nerves signal the vibration of the vocal cords. Another is that the sound comes from vibrating blood vessels or the muscles of the larynx. However they do it, they seem to be able to do it when they want, which is not always when they are happy and content.
Besides the common purring a cat sometimes “lurps” or “yowps” which are low level outbursts, and purring also varies from cat to cat. While the scientists aren’t sure how cats make the sound, they do know a lot about the sound itself. The frequency of a house cats purr is between 25 to 150 vibrations per second as compared to a cheetah which is around 20hz. These vibrations are in the frequency range known to stimulate bone growth and healing. An even newer theory is that purring releases endorphins that reduce pain. This may be the reason that cats are often used as therapy animals.
Still scientists are not sure why cats purr but as any cat owner knows they do it when they are being held or patted, or when eating. Female cats sometimes purr when giving birth and or while nursing. Domestic cats have been known to purr when injured, sick, in pain or dying, which certainly would tie into the endorphin theory. In some circles, purring is thought to be an attempt at friendship or could be a signal of specific intent. It may be that cats know more about our behavior then we do about there’s and while cats are still a mystery, they hold a place in our society that is clearly mutually beneficial, even if they seem to think they are above it all.
Other animals that Purr: