https://getpocket.com/explore/item/8-facts-about-the-animals-of-chernobylSeems the critters don't live long enough life span wise for the radiation to build up enough to harm them or something, BUGS actually took it on the chin and thinned out greatly, SO.. all us gamers who play fallout and STALKERS (based around Chernobyl.) are in for a big let down! the place is almost Eden, deadly as hell still to humans however. So after we blow ourselves up, nature will be like "Meh, good riddance." and pick up where she left off.