Animals can be traded for cash and conservation credits.
Before you can trade an animal, you must send it to the Trade Centre. Animals cannot be traded when they are juvenile, sterile or elderly.
If an animal can't be traded or released to the wild, it can be rehomed; doing so costs money. Once an animal is rehomed, there is no way to get it back.
Trade in Franchise Mode
You can only trade for conservation credits in Franchise Mode. To list the animal on the market for Conservation Credits, select 'Trade.' Other players will then be able to adopt your animal while the animal is listed. If the animal isn't adopted before the listing expires, it will return to the Animal Storage.
Quick Sell
In any mode of the game, you can quickly sell the animal for cash. This is instant but doesn't generate Conservation Credits.