You shouldn't try islands with animals that can drown ,but further ,it works with most animals. I've tried it with crocs and hippos and it's fine.
It does not work with tigers ,that goes wrong.
It works with elephants and rhinos very well.
My hint is that you use deepest water closest to the fence ,and that you will put a fence around the water (rnot between the land and the water) ,so the animals can swim ,but not climb the land on the other side of the water.
Animals will escape trough water, a piece of land with water around at all sides doesn't work as an exhibit ,the game will still say animal usch isn't contained and all this mess.
I believe animal islands work for pretty much any animal ,if you manage them well.