Purring is an extraordinary sound and it isn’t exactly clear how cats do it. Not only domestic cats purr – many of the larger members of the cat family can also generate this vibration.
The behaviour stems from kitten-hood, as the mother returns to the den and quietly signals (to avoid attracting attention from predators) that all is OK by purring to her kittens, they in turn suckle and purr at the same time. Cats will also purr when they are sick or injured; there are various theories for this – the frequency of the purr in sick animals differs from the healthy purr and it may have healing properties or it may be self-soothing when the cat feels at its most vulnerable.
