Why Do Cats Purr?

Excerpted from Energy Healing for Animals (Sounds True):

Purring is believed to come from vocal folds or cords. While this expression has no anatomical or physical presence in the body, if you hold a purring cat and feel it, the strongest source of the purr is the fifth chakra. Purring can be about food, but it is also very much a loving expression. In fact, studies have shown that purring is actually healing; the low-frequency vibration is said to help build bone density, heal the heart, and is linked to weight loss.