It's likely you're thinking of another game, potentially Sonic Adventure DX: Director's Cut, as that one does feature Chao. If you're asking about the small animals in Sonic Adventure DX: Director's Cut, then you'll need to provide some more context about what you're looking for. For example:
* Specific types of animals: Are you looking for a list of all the different Chao types?
* Gameplay aspects: Are you looking for information on how to care for Chao, what they can do, or how they can be used in battles?
Please provide more information so I can give you a helpful answer.