If you're a cat lover, chances are your favorite feline has given you a massage with their rhythmic, kneading paws.

Colloquially called “making biscuits,” kneading is common among kittens and full-grown cats alike—but animal experts say they don’t know quite why they do it.

Scientists have a few theories, some of which are outlined by SciShow’s Hank Green in the video above. One theory is that your kitty’s trying to mark their territory—yes, that “territory” is you—with the scent glands in its paws. Another is that kneading is a “neotenic behavior,” or a juvenile trait that sticks with cats into adulthood. Kittens knead their mama’s belly to stimulate milk production—an act that’s nearly identical to that strange Shiatsu business it’s doing in your lap.

Green does point out that domestic cats knead, whereas wild cats don’t. He attributes this to the fact that house cats were selected over thousands of years for social, friendly traits. While occasionally painful or obnoxious, kneading one’s owner is definitely a loving act, a way of letting you know that they are comfortable and feel safe.

[h/t SciShow]

Banner images via Wikipedia // CC BY-SA 3.0