The original two Zoo Tycoon games have a few humorous easter eggs and simple gags to keep players entertained.
- If you name and exhibit Super Croc, you will get a Deinosuchus in your animal list.
- in ZT1, if you place a mermaid statue in a tank, it will become real
- The Emperor Penguin will kill other animals in a suitable exhibit.
- You can unlock the Unicorn in Zoo Tycoon by naming an exhibit Xanadu.
- In Zoo Tycoon if you name an exhibit Cretaceous Corral you will unlock the Triceratops
Zoo Tycoon 2
- Sometimes in the Extinct Research Lab in Zoo Tycoon 2, The scientist will be replaced with a Killer Penguin.
- If you quickly spin the globe in Zoo Tycoon 2 with at least one expansion installed, a screaming noise can be heard.
- if you place 5 coffee stands, "Caffeine Craze" will be enabled for adult guests.
- If you place 5 cotton candy carts, "Sugar Shock" will enable for young guests.
- Occasionally, when placed, the Glacier object will hold a caveman. After a short while, the glacier will melt, freeing him. He will act as a normal guest once freed.
- On medium or high graphics, Stokesosaurus will wear glasses while painting.