That's a good question. Animals seem to be thriving in and around Chernobyl. Yeah some may die younger because of the radiation, and some may be dealing with cancers and deformities. The animals that graced the area are starting to come back. I wonder if they can smell or sense the radiation and are able to stay away from any hot spots. I hear brown bears, wolves, deer, etc. Pretty much what we have in the states to some extent.
A lot of animals still live around there. And I imagine they will start to move more in. But like I said, I have a feeling the animals know where pockets of radiation may be, so they're probably finding any inhabitable land.