The whales can be seen in the Hawaii Checkout mission (But you have to look closely if you're altitude is too high) , and the elephants, giraffes and zebra in the Game Park Patrol mission.
About the only way I can think of to make them visible "on demand" is to make them "flyable". I did that with the "Humpback Whale" by grabing the needed files from the "Orca" killer whale add-on. I haven't tried the other animals yet, although it should work for the Zebra, at least, if ou find the "Black Stallion" (I think that's what it's called) and grab the "panel" and "sound" along with the .air and .cfg files from that and put them in the "zebra" folder.
But, there might be more too it than that, but it worked for the Humpback.
