It takes a very high radiation exposure to cause acute radiation syndrome—more than 0.75 graygrayA gray is the international unit used to measure absorbed dose (the amount of radiation absorbed by an object or person). The U.S. unit for absorbed dose is the rad. One gray is equal to 100 rads. (75 rad)radThe U.S. unit used to measure absorbed radiation dose (the amount of radiation absorbed by an object or person). The international equivalent is the Gray (Gy). One hundred rads are equal to 1 Gray. in a short time span (minutes to hours). This level of radiation would be like getting the radiation from 18,000 chest x-rays distributed over your entire body in this short period. Acute radiation syndrome is rare, and comes from extreme events like a nuclear explosion or accidental handling or rupture of a highly radioactive source.
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“This problem with the spectacled bears is not just in Leipzig [Zoo],” Mr. Noetzhold told the BBC World Service. “There are other zoos in Europe and overseas having the same problem. And so we’ve had an international working group of zoo vets looking at this for some time already.”

Gerard Baars, director of the International Bear Foundation, said he had never seen such a condition before. “I could hardly believe it is a bear although I have been dealing with bears all my life,” he told the BBC’s Europe Today programme. The picture in the advertisement was perhaps chosen for the reason mentioned by Baars. Even the director of the International Bear Foundation didn’t know it was a bear. Readers who saw the ad likely wouldn’t initially identify the animal as a bear, either. Jan Woitas and the European Pressphoto Agency were credited for the photograph that was used in the ad. It appeared to be from 2009. Also on Nov. 5, 2009, the Associated Press posted a video of Dolores, Bianca, and Lolita at the Leipzig Zoo. The zoo official, who was not identified, spoke of research that was underway about the issue with the bears. He also mentioned that other zoos had seen similar problems with such bears. Here is a video. At least two blogs mentioned that Dolores died in 2011. We were unable to confirm this information with any credible source. However, one thing we can say for sure is that she was not a “new species” that was “taking over at Chernobyl.” For further reading, Scientific American reported on the Chernobyl Exclusion Zone in December 2020. The story looked at the possibility of “lingering radiation effects on animal populations.”