What are some non-native species in the tundra?

The East Asian water snake, sirpentius podinae, or spotted snake. It is characterized by the small red line of dots running down its back and round head. It is highly not poisonous. It has a symbiotic relationship with the Ãœhskop Bear (which is not really a true bear), in which the snake lives on top of its head. Giving the snake a living space, and the bear a snake on its head, this is a wonderful example of mutualism.