You can't you have to buy it. (in the game that is) and it doesn't cost stars.
An Ocelot is a cross breed between a Cheetah and a Puma in Tap Zoo
Reach level 19 and you can buy it for 49 stars
Walrus and a owl
A macaw
A Rhea and a Jaguar.
a howler monkey
A zeian
You have to cross breed a gorrila and an Africian buffalo.
Rhino
Breed a Fitch with an Emperor Goose.
Cross breed a macaw and an alligator
Cross breed a fox with a leafy dragon