Keleios Faith
It's also because their nails shed similar to like a snakes skin, so they have to slough off the dead nails.... >.> Sorry, been around domestic cats my whole life, and love the big cats of the wild...
yep, correct, it's usually either for territory marking and/or to remove the shed layers of their claws.
it's also like a form of exercise, it feels good and is a way to stretch and work the muscles in their legs. It's probably one of the reasons a lot of cats will scratch on the nearest attractive surface when feeling playful and frisky.