The Chernobyl exclusion zone remains an active research site for studying long‑term radiation effects, and its stray dogs are frequently observed by scientists and volunteers. Recent videos showed dogs with a blue tint, prompting concern that radiation had caused visible changes. Investigators and volunteers now believe the animals were stained by blue dye from a leaking porta‑potty rather than by radiation. Genetic studies in the area have found differences in the dogs’ genomes, but those differences may be explained by genetic drift in an isolated population.
Blue Dogs of Chernobyl? Porta‑Potty Dye, Not Radiation, Likely to Blame
The Chernobyl exclusion zone remains an active research site for studying long‑term radiation effects, and its stray dogs are frequently observed by scientists and volunteers. Recent videos showed dogs with a blue tint, prompting concern that radiation had caused visible changes. Investigators and volunteers now believe the animals were stained by blue dye from a leaking porta‑potty rather than by radiation. Genetic studies in the area have found differences in the dogs’ genomes, but those differences may be explained by genetic drift in an isolated population.
00:14, 05.11.2025Science
Blue dogs in Chernobyl: What happened and why it’s not radiation
Scientists have studied the animals around the Chernobyl Nuclear Power Plant for decades, treating the exclusion zone as a unique, accidental long‑term experiment in environmental radiation exposure. Among the most observed animals are the stray dogs that roam the site and nearby towns.
Videos showing several dogs with an unusual blue tint recently circulated online, prompting speculation that the coloration might reflect radiation‑driven genetic change. Volunteers and verification sources quickly investigated and now believe a far simpler explanation is most likely: the animals were stained by chemicals from a leaking porta‑potty.
Background: Chernobyl’s living laboratory
On April 26, 1986, the Chernobyl Nuclear Power Plant near Pripyat, Ukraine, suffered the worst civilian nuclear accident in history. Today, the Chernobyl Exclusion Zone (CEZ) remains both a place of tragedy and an active field site where researchers study long‑term radiation effects on wildlife. Studies have documented changes across species — frogs with darker pigmentation, barn swallows with deformed feathers and air sacs, and wolves showing surprisingly low cancer rates for a top predator.
The dogs of Chernobyl
Groups such as Dogs of Chernobyl trap, vaccinate, sterilize and tag the region’s strays. Many of these animals are believed to be descendants of pets abandoned during the evacuation. The organization estimates roughly 250 dogs roam the Chernobyl Plant grounds and about 225 live in nearby Chernobyl City.
Genetic comparisons between CEZ dogs and nearby control populations have found differences, but attributing those differences directly to radiation is difficult. A 2024 study suggested that genetic drift — random changes in an isolated population — could explain some of the observed divergence.
What likely caused the blue color?
"We are on the ground catching dogs for sterilization and we came across three dogs that were completely blue," the nonprofit Clean Futures Fund wrote on Instagram. "We are not sure exactly what is going on... we are attempting to catch them so we can find out what is happening."
Verification reporting by Storyful and statements from volunteers indicate the animals probably accessed a leaking porta‑potty and became stained by blue dye or disinfectant chemicals. Apart from their unusual coloring, the dogs appeared active and healthy in the videos and photos circulating online.
Bottom line
While the Chernobyl exclusion zone continues to yield important scientific insights, this episode is a reminder that not every striking observation will prove to be a radiation effect. In this case, the most plausible explanation is mundane and animal‑typical: dogs will be dogs, and they sometimes roll in gross stuff.