While it is dangerous for humans to live in many parts of the world—Chernobyl being a prime example—the animal kingdom has not just survived, but flourished. In the absence of humans, nature has reclaimed itself.
There is an excellent series by PBS called "Radioactive Wolves" discussing how the animal kingdom has thrived in the exclusion zone. Even with the elevated levels of radiation causing twice the normal rate in birth defects—something that would be unacceptable for a human populace living there—the animals don't seem too disturbed. In fact, the land has become a haven for animals. Beavers, which had been wiped from the area due to the farming demands, have returned and restored one of central Europe's great marshlands.
Naturally, there are evolutionary consequences to living in this area for these animals. In Chernobyl in particular, there is a type of Radiotropic Fungus that eats the radiation. After the Japanese Tsunami, there was a discussion on how the fungus could be utilized in future radioactive disasters. So while living in these areas is less than suitable for humans, attention should definitely be paid to how these animals manage to live, adapt, and thrive.