The Mutant Wolves of Chernobyl Have Evolved to Survive Cancer

In the shadow of nuclear disaster, these canines show remarkable resilience to the deadly disease.

• The Chernobyl Exclusion Zone (CEZ) has quickly become a 1,000 square-mile science experiment, as experts use the highly irradiated zone as a chance to understand animal biology placed under those extreme conditions.
• Biologists from Princeton University studied wolves in the CEZ for a decade and found that they’re thriving compared to neighboring wolf packs, likely due to reduced human contact and genetic mutations that protect again cancer.
• The biologists are working with other cancer experts to see if these particular mutations could have therapeutic uses for humans.

On April 26, 1986, disaster struck the small Ukrainian-Belarusian border town of Chernobyl, (then part of the Soviet Union) when a series of steam explosions led to a nuclear meltdown. The apocalyptic event impacted hundreds of thousands of people and greatly impacted the surrounding environment.

But nearly 40 years later, something strange is happening. The Chernobyl Exclusion Zone (CEZ), a roughly 1,000 square mile perimeter around the nuclear plant, is slowly becoming one of the world’s biggest science experiments for exploring the long-term effects of ionizing radiation. While humans might’ve abandoned the area, other animals stuck around.

In 2016, a study found that the Eastern tree frogs (Hyla orientalis) in the CEZ exhibit different characteristics than their neighboring cousins, and in 2023, another study discovered distinct genetic differences between Chernobyl dogs and dogs living only 10 miles away in Chernobyl City. Now, Princeton University biologists Cara Love and Shane Campbell-Stanton are exploring another strange mammalian characteristic of the CEZ—its unexpectedly thriving wolf population. The results of the decade-long study were presented at the Annual Meeting of Society of Integrative and Comparative Biology in January.

Analyzing wolves in the CEZ is particularly interesting because they’re apex predators, a.k.a. the top of the food chain. This is usually a privileged position in an ecosystem, but when that ecosystem is inundated with radiation, these animals are forced to eat irradiated prey that ate irradiated plants that grew out of irradiated soil. Basically, it’s radiation all the way down.

This would seem to suggest that wolves would be particularly impacted in the CEZ, but Love says that isn’t happening. In fact, she told NPR earlier this month that wolf populations in the CEZ are actually seven times more dense than in protected wildlife areas in neighboring Belarus.

“Gray wolves offer a really interesting opportunity to understand the impacts of chronic, low-dose, multigenerational exposure to ionizing radiation,” Campbell-Stanton said in an NPR interview. “As an evolutionary biologist, the very first question in my mind was whether or not this radiation was enough of a stressor to actually be a selective pressure.”

In 2014, the Princeton team attached collars to these CEZ wolves with both GPS and radiation dosimeters, in an effort to understand the population’s response to Chernobyl’s cancer-causing radiation. They discovered over time that the wolves were consistently exposed to radiation six times higher than the legal limit for humans.

Love and Campbell-Stanton’s theory is that wolves are experiencing a kind of rapid natural selection, one likely caused by the equally rapid change in their surrounding environment. Some wolves within the CEZ contained genes that made them more resistant to cancer than other wolves. While still getting cancer at the same rate, these resilient canines simply weren’t as impacted, allowing them to pass on those genes to a future generation.

“So in general, we found that the fastest-evolving regions within Chernobyl are in and around genes that we know have some role in cancer immune response or the anti-tumor immune response in mammals,” Campbell-Stanton told NPR.

While the data shows a clear genetic cause behind the CEZ wolves’ cancer-resistance, Campbell-Stanton is quick to point out that these wolves are also free from other biological pressures—most notably, humans. The team is currently working with cancer specialists to see how these results could impact human health.

For decades, Chernobyl has been characterized as an immense ecological disaster (which it definitely was), but in the past decade, the CEZ has also looked more and more like an unprecedented scientific opportunity.

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