Radioactive wild boars have lived in German forests for decades. Scientists said their radioactivity was from the 1986 Chernobyl nuclear disaster. However, other animals are not as radioactive. They do not have as much radioactive caesium in their bodies. This has puzzled scientists. They dubbed this mystery the "wild boar paradox". They say the wild boars' radioactivity is from nuclear weapons tests from last century.

Scientists believe wild boars are radioactive because of their love of truffles. These absorb caesium particles in the ground. The levels of caesium in boars mean they cannot be eaten. This has led to a reduction in the hunting of the animals and an increase in their numbers. A geochemist said he doesn't know why the effects of nuclear weapons testing on the environment has been "largely forgotten". He said soil pollution will "haunt generations to come".