A polydactyl cat is a cat born with extra toes on one or more paw. This can sometimes make the cat look like it has hands with thumbs! These are also known as ‘Hemingway Cats’ or ‘Mitten cats’.
Source: https://healthypets.mercola.com/sites/healthypets/archive/2017/03/09/polydactyl-cats.aspx
I have one! Hes beautiful!