A cat's paws are the most sensitive part of its body, and while cat clawing makes cat paws lethal weapons, the velvet-soft pads of their feet are exquisitely designed for any number of uses including kneading a mother cat for milk.
When young and still relying on the mother for food, kittens will push rhythmically with their front paws against the mother cat's breasts to stimulate the release of milk. Called kneading because it resembles the way bread dough is made, this behavior can sometimes carry over into adulthood resulting in many felines kneading against soft objects when they seem to feel particularly happy and satisfied.
Although we can't know for sure, we suspect the emotions hearken back to feel-good moments of nursing during kitten-hood. As a result, adult cats who knead an owner's lap may actually be declaring their love for a surrogate human "mom."
Other Possible Explanations for Kneading
While it might be comforting to think of your feline friend as kneading you as a sign of affection, there are a few other hypotheses circulating around the animal behavior science field to explain the phenomenon of adult feline kneading.
Since felines were domesticated over 2,000 years ago, some scientists believe that there are still several instinctual behaviors in house cats that harken back to their wild roots; when wild cats are settling in for a rest or preparing to give birth in the wild, for instance, they oftentimes would pat down foliage to make a soft surface on which to lay.
Another possible scientific explanation for why cats knead is that the pads of their paws have scent glands in them, which are used to mark and lay claim to an area, either for sexual "advertisement" or for territorial ownership. Cats may be kneading an especially soft place they want to claim as their own.
Paw Pats, Foot Treading, and Odd Behaviors
A cat may also use soft paw-pats to test objects for safety by tentatively tapping on a surface to measure temperature, texture, or stability. These small bops of the paw on an object—or sometimes another cat or human—is a way felines use their multi-purpose paws to interact with the environment around them and can also be used to initiate play with or dole out light reprimanding to other cats or humans.
Another odd behavior most cats display is what's known as "rear-foot treading," or moving quickly back and forth between each foot and appearing to shake their bottoms. While male kitties do this after they've mounted the female during breeding, for example, both boy and girl cats demonstrate rear foot treading during play and hunting when preparing to launch an attack.