Answer:
Runs over fields and woods all day. Under the bed at night sits not alone, With long tongue hanging out, Resting at your feet until we go for a walk
I am always hungry, I must always be fed. The finger I lick will soon turn red.
We are all around, yet to us you are half blind. Sunlight makes us invisible, and difficult to find.
I am black when I am clean and white when I am dirty?
Whoever makes it, tells it not. Whoever takes it, knows it not. Whoever knows it, wants it not
You use it between your head and your toes, the more it works the thinner it grows.