Completing the "Paradise Island" scenario will reward the player with the mythical Unicorn as an adoptable animal. However, it can be unlocked earlier by renaming an exhibit to "Xanadu".

The name "Xanadu" seems to be a reference to at least one of the following:

•The former capital of Shangdu, which featured unicorns on its currency during the Yuan dynasty.
•The 1980 film Xanadu, a musical fantasy.
•The 1988 comic book series also called Xanadu, which featured unicorn characters.