Wild adult cats don't knead, but tamed (spoiled) adult house cats love to dig into an owner's skin. The painful activity is often referred to as "making biscuits," likely because they prefer to push their claws into our soft bellies.  

What's the science behind this affectionate yet cringe-inducing behavior of domesticated adult cats? SciShow explains some of the leading theories: 

      Image credit: marinaks/Shutterstock