Kneading is a common behavior seen in domestic cats, in which the feline pushes in and out with its front paws, alternating between left and right.
Cats often perform this motion — sometimes called "kneading dough" or "making biscuits" — on soft surfaces, including pillows, blankets, other animals and even people.
It's unclear why cats knead, but a number of hypotheses exist.
The most oft-repeated explanation states that kneading is a leftover behavior from kittenhood. During nursing, a kitten will knead the area around its mother's teat to promote the flow of milk.
In adulthood, a cat supposedly will knead when it's feeling happy or content because it associates the motion with the comforts of nursing and its mother. Adding further weight to the explanation: Some cats even suckle on the surface they're kneading.
Another hypothesis proposes that kneading harks back to a time before domestication, when wild cats supposedly patted down foliage to make a soft surface for sleeping or giving birth. The behavior may now be an instinctual part of settling down.
On the other hand, kneading may just be another way for cats to scent and claim an area — cats have scent glands in the pads of their paws.