They serve as hooks, crampons, switchblades and chisels. A cat's claws are the Swiss Army knife of the feline toolbox. They are essential in practically every role that a cat plays.
Claws are indispensable! Yet, in many households, a cat and his claws are separated via surgical declawing -- all for the sake of the sofa. While all cats need to scratch, few need to be declawed. Would you cut off your entire fingernail?