The animals knew better than humans how quickly actually harmful levels of radiation would recede. The entire standard that was developed for harmful levels of radiation was based on a scientific researcher’s error. That error has been recognized and admitted, but the standard remains; mostly because the scientists have never independently tried to develop a new one, because of the institutional problem of everyone publicly admitting they all might be wrong.
The animals knew better than humans how quickly actually harmful levels of radiation would recede.
The islands where we tested atomic bombs following WWII is further circumstantial evidence to support your theory.
There is a lot of life there, something that wasn’t supposed to happen for a long time yet.