Why do cats knead with their paws?
For grown-ups: the science
Cats knead because the move began when they were kittens drinking milk, and grown cats often do it when they feel cozy.
Kneading is an instinctive feline behavior. In nursing kittens, rhythmic paw pressure can stimulate milk letdown. Adult cats may knead during relaxation, and scent glands in the paw pads can deposit scent on surfaces, though kneading does not always have one single cause.
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Transcript
Look at that cozy cat pressing its paws on the blanket. Why does it make little push-push moves?
Kittens press their paws on their mother while they drink milk. The pushing helps milk flow, and it feels safe and cozy.
As cats grow, they may knead soft things like blankets, beds, or your lap. It can mean they feel relaxed and comfortable.
Cats also have scent glands in their paw pads. Kneading leaves a little of their own smell on a favorite spot.
So kneading began as a kitten milk-helping move. Grown cats often do it when they feel cozy or claim a comfy place.