I have a mate who is a photographer (just starting in the industry) and works as Wayne's (dude who takes most of the zoo and ralph photos) assistant on Zoo photo shoots.
He also started his own website, but claims most of the work you get is mainly by word of mouth and getting out there and introducing yourself to everyone.
I say he is a photographer because his camera is worth $30k and this is his only form of income.
Here is his website if you're interested.
http://www.twoshinephoto.com