Purring is vital for the survival of newborn kittens. They are born deaf and blind, but they do feel vibrations. These vibrations are perfect homing devices, guiding newborns to the protective warmth of their purring mother and to their first meals.
Cat owners are familiar with the relaxing purrs of cats as they cuddle and stroke them. These purrs signal contentment, with the added benefit of lowering the blood pressure of those stroking them. Many cats quickly figure out another benefit of purring — receiving food and attention from their owners. Since most owners lavish attention on their cats when they purr, cats often purr when they want affection and treats.
However, not all cat purrs are purrs of contentment. Cats also purr when they are stressed, in pain or severely ill. Sometimes cats at the end of life will purr. Purring releases endorphins which help reduce pain. Studies find that purrs vibrate at a low frequency of 25 to 100 HZ. These frequencies promote bone healing and ease muscle pain. Clinical trials of people receiving ultrasound treatments on fractures and muscle injuries have proven that low-frequency/intensity ultrasound accelerates healing. Purrs, therefore, can reassure and soothe, they can promote healing, and reduce pain.
Also, did you know that although our domestic cats are not the only animals who purr? Their purrs are unique because they are the only ones who do so whilst inhaling and exhaling. Cheetahs and cougars are examples of big cats who do purr whereas lions, leopards and tigers do not. Gorillas, raccoons, rabbits, bears, foxes, guinea-pigs and hyenas are examples of other animals who purr although the mechanisms that produce the purr vary between each species, as do the meanings of their purrs.