I know a lot of people want whales and dolphins in the game -
However - I think it's important that you take this chance to spread some much needed awareness of how much these animals are abused in zoos all over the world. I definitely think you could include these animals as
rehabilitation exclusives, meaning you can only have them during campaigns/quests where you get an injured animal and send them back as soon as they're healthy. If you're not going to do this, and are just going to include them as normal animals, please at least make it impossible to make them very happy due to space needs, so players will at least get the message from complaining guests