The Crayola Colorful Creatures app needs to be played in order. You start with the Elephant and new creatures will appear as you play through the app.
Once you have played with a creature you are able to play with it again as often as you like!
There is also a "reset" button in the in-app settings that allows you to reset the globe to the beginning. If you decide to reset the globe you will begin again with the Elephant.