Answer:
I am always hungry, I must always be fed. The finger I lick will soon turn red.
Dies half its life. Lives the rest. Dances without music. Breathes without breath.
Gets rid of bad ones, short and tall. Tightens when used, one size fits all.
They have not flesh, nor feathers, nor scales, nor bone. Yet they have fingers and thumbs of their own.
Bright as diamonds, Loud as thunder, Never still, A thing of wonder.
I am owned by Old McDonald.