Yeah you have to start low. My dad worked for a zoo for a short time and his job was washing out the pens/enclosures - poop duty. I was told once someone was in one of the 'coveted' positions, like working with the big cats, they'd stay there for life unless they transferred to a different location (or retired).
After the animal training thing, I wanted to work in graphics arts but my junior high art teacher told me and my friend that although we had talent, don't chase it as a career because it was too difficult to make money. I wish I hadn't listened to him. I love seeing you post your art pics and doodles, I'm so happy for you that you went for it and succeeded! It's awesome!