One of the secret animals in the jungle is the Bunny Gator. Play as any one of the other gators and after 2,000 meters or so you should see the Bunny Gator appear. Jump onto the Bunny Gator and ride it and from there you will have yourself a new Bunny Gator.
Another one of the secret jungle animals is Dhinoceros, the secret rhino. To unlock Dhinoceros, you have to have the rhino enclosure. Then, ride all seven of the different jungle animals in one run, you can do this in any order. You will see the Dhinoceros appear and you can catch it.
H.R. Tiger is the secret Tiger character. To earn H.R. Tiger, ride for a really long time on one single tiger after it gets angry. After a very long time riding it you will unlock H.R. Tiger.
The secret toucan character is called Threecan. The unlock method is to first unlock one of the other toucans. Then once you do, ride the toucan and do a 100 meter jump and land on any other animal. Once you do, the threecan will appear and you will be able to jump on it and catch it.
The secret gorilla is called the Guerrilla. As of now, though, nobody has come forward with a way to unlock the secret gorilla. We will keep you posted when we figure out how to unlock the secret gorilla.
Two of the other types of animals in the jungle are the Boar and the Hippo. As of right now, nobody has quite figured out how to unlock the secret versions of either the Boar or the Hippo. We will keep you posted as soon as we figure out how to unlock their secret counterparts. Bookmark this page and keep checking back as its updated every time we find a new secret animal.