Land owning in zoo's and wildlife parks?

I would like to know if any one knows of any major land owning organizations in zoos or wildlife parks???Land owning in zoo's and wildlife parks?
Most parks in the United States are owned by the National Park Service, but the most public land in the United States is held in trust by the Bureau of Land Management. While these are not 'parks' they hold much more as far as animals and vegetation than the 'parks' do.