Answer:
I am asleep when you are awake I am awake when you fall asleep. I can fly but no feathers to aid my flight.
The shorter I am the bigger I am.
My keepers feed me colored balls. With sticks they store on my den walls. Sometimes I store them in my pouch. Sometimes deep in my belly; ouch!
When set loose I fly away. Never so cursed as when I go astray.
What is eaten but can also eat?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.