Snakes never really stop growing. There are specimens of all species that get really big and some that stay small. It all depends on husbandry and feeding. I wish I could get on my comp and quote some sites but it decided to take a nasty dump on me and I need to get it into my comp guy. I know the largest ball off the top of my head was 6ft. Columbians can be great pets as long as they are properly cared for. You can not skimp on feeding them appropriately and expect them to still be sweethearts. I know of one columbian that honestly should have been put down because of her owner neglecting her. She was aggressive beyond belief. She would track me every time I visited her owner. I also know a burmese thats the same way and has attacked people because of neglect. Ball Pythons are a bit more forgiving. I know my poor girl wasn't fed for almost 6 months because the people who were watching her didn't have the money. She was also in a really disgusting cage, with no heat, or water. I picked her up and she was still sweet to me. I've gotten her fed 2x since I got her back and she is calm and loving to me. She is very head shy now but I am working on that. She hasn't even tried to strike at me or my son and he is fascinated with her and bangs on her enclosure.