All the money he earns goes to the zoo, I read.
But that zoo gets so many visitors every year. They earn enough money by selling tickets and make some nice profit too.
I am co-founder and secretary/webturtle of Europe´s largest Reptile Zoo Reptielenzoo Iguana Vlissingen
, so I know something about that. We would wish we had 10 % of the visitors Steve´s zoo gets yearly. I guess they have over 1 million visitors every year.