In DragonVale you can acquire a multitude of dragons. Unfortunately, some of their habitats are small; some can only hold 1 dragon (the nerve)!
The problem is, I wasn't aware of this fact. Probably because I can't be bothered to read tutorial hints. So, there I am all excited about buying another Earth Dragon, only to realize I would have to buy another habitat to keep him in!
Can I upgrade my existing habitats to hold more dragons?