Answer:
My teeth are sharp, my back is straight, to cut things up it is my fate.
Hard to catch, easy to hold. Can't be seen, unless it's cold.
I am nothing but holes tied to holes, yet am strong as iron.
They have not flesh, nor feathers, nor scales, nor bone. Yet they have fingers and thumbs of their own. What are they?
Everyone has it and no one can lose it, what is it?
I can only be played on a windy day