Episode Description: After their encounter with the Dodo Bird, the Wild Kratts decide to try out Aviva's Time Trampoline again. This time to visit with the extinct Tasmanian Tiger. But their trip doesn't go as smoothly as they hoped. Not only do they run into the ancestors of Donita and Dabio - who are trying to get rid of all the Tasmanian tigers - but the Wild Kratts have to defeat Zach, who is hatching a plan to keep them trapped in the past forever! Science Concept: Extinction - different types of animals can go extinct and disappear from the planet in a number of ways - habitat loss, overhunting, etc. Once an animal goes extinct, it is lost forever.