I first visited Chernobyl in 2016, 30 years after the explosion at Reactor Four. I expected silence and scarcity – a lifeless place, defined by radiation. Instead, I found beavers swimming beneath a nuclear power plant.
When the reactor exploded on 26 April 1986, many assumed the surrounding land would be biologically dead for generations. The exclusion zone – the area where radiation is highest and access is still restricted – covers roughly 2,600 km² on the Ukrainian side, about the size of Luxembourg.
When neighbouring areas of Belarus are included, the affected landscape stretches to more than 4,500 km². With that as a starting point, it was hard to imagine a future Chernobyl that was anything other than a wasteland.
In the days and months that followed, the evidence seemed to support that view. The pine forests closest to the plant absorbed such intense radiation that their needles turned an orange-red and died, creating what became known as the Red Forest. Early studies reported small mammals and invertebrates were disappearing in heavily contaminated areas.
And yet, 30 years on, there I was, watching dark heads cut slow arcs through the cooling ponds at the Chernobyl Nuclear Power Plant itself, beneath the vast concrete shell of reactor four.
A glance upward reminded me this water had been engineered to keep a nuclear reactor from overheating. Now it held a functioning dam with beavers behaving like beavers.
Chernobyl’s mythology presents the place as being filled with grotesque mutations – two-headed fish and other monstrosities. Instead, a white-tailed eagle and a migrating osprey fished as if this were any other wetland.
Great white egrets worked the shallows in the reactor’s shadow. A grey wolf burst briefly from the reeds, then vanished again – running away, not patrolling some apocalyptic wasteland.
What people expect from Chernobyl is a catastrophe frozen in place: ruins, silence, and a landscape visibly broken.
Now, nearly 40 years on, the exclusion zone has become one of the most unusual ecological experiments on Earth, shaped not just by radiation but by abandonment and time. The usual ecological rules no longer apply, leading Chernobyl to have some truly weird wildlife.
1. Large mammals are flourishing
Usually, large animals are the first to disappear after an environmental disaster. They reproduce slowly, require large territories, and are especially vulnerable to human pressure. But in Chernobyl, they’re thriving.
Large mammals have returned in numbers that defy expectation. Wolves roam widely across the exclusion zone. Brown bears have reappeared after long absences. European bison move through abandoned farmland.
Przewalski’s horses, introduced in the late 1990s, now range freely. Beavers have recolonised rivers, canals and cooling ponds, while deer, boar, moose and lynx occupy habitats that were once heavily managed or fragmented by agriculture.
And at first glance, it doesn’t appear that the radiation is bothering them. People often imagine Chernobyl’s wildlife is filled with monsters born of radiation, but scientists working in the zone are keen to reset those expectations.
Clear, dramatic physical deformities in large mammals are rarely documented because animals born with severe abnormalities rarely survive long enough to be observed. Meanwhile, the relatively short lifespans of wild mammals mean long-term effects are difficult to detect in the field.
The absence of monsters does not mean the absence of impact, of course, but it does mean that the impacts are not playing out in the ways popular culture expects.
Instead, the decisive factor appears to be the sudden absence of people. Hunting stopped. Roads fell apart. Farming ceased. Human disturbance – often the most consistent pressure on large wildlife – dropped almost overnight.
“This matters,” says evolutionary biologist Germán Orizaola, who has been studying the effects of radiation in Chernobyl since the spring of 2016, “because if you focus on the species that are doing badly, you can blame radiation. But often the environment itself has changed. Ecology and the absence of humans are huge factors here.”
The result is an inversion of expectation: landscapes that still carry radioactive contamination, yet support apex predators and large herbivores at densities rarely tolerated in human-dominated Europe.
Chernobyl sounds like a place where nothing big should live. Instead, big animals are among its most visible residents.
2. The frogs that turned black
One of the clearest examples of the impact of Chernobyl’s radiation – and of evolution in action – comes from the region’s frogs.
You just need to look at them to see it – the Eastern tree frogs living inside the exclusion zone are markedly darker than those found elsewhere in Ukraine. The difference is so striking that, according to evolutionary biologist Dr Germán Orizaola, it barely needs measuring.
“You go to Ukraine, you show me a frog, and I will tell you if it’s from inside or outside Chernobyl,” he says. “The difference in colour is not subtle. Frogs inside are simply much darker.”
Frogs from contaminated areas are, on average, around 40 per cent darker than those outside the zone. Darker skin in frogs corresponds to higher levels of melanin, a pigment known to protect tissues from radiation by neutralising some of the cellular damage it causes.
Rather than radiation creating something new, Orizaola’s work suggests that natural selection has favoured an existing trait.
“Even in normal populations, a few frogs are naturally darker,” he explains. “Those individuals likely survived and reproduced slightly better.”
Over just a few generations, that advantage became visible across the population. Evolution here has not produced something new – it has favoured what already worked.
Crucially, the frogs show no clear differences in age, immune function or overall health. What has changed is not their overall condition, but which traits are being quietly favoured.
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3. Radiation-eating fungus
If black frogs stretch our idea of adaptation, some of Chernobyl’s fungi push it even further.
Inside the ruined reactor buildings and across parts of the exclusion zone, scientists have found dark, melanin-rich fungi growing where almost nothing else can survive.
They coat walls, creep across debris and colonise environments saturated with ionising radiation – even in places that should be profoundly hostile to life.
Even stranger, some of these fungi appear to grow more vigorously in high-radiation environments.
Laboratory experiments suggest that melanin in these organisms may do more than simply shield cells from damage.
In some species, exposure to radiation is associated with changes in growth and metabolism, leading researchers to propose that melanin may help fungi tolerate, or even exploit, radiation.
Whether these fungi are truly ‘using’ radiation as an energy source remains an open question. What is clear is that they exploit an extreme niche that barely existed before 1986. When the reactor melted down, new ecological opportunities emerged for microbes able to tolerate conditions lethal to most life.
4. The dogs that are evolving
Hundreds of feral dogs still live in and around the exclusion zone, descended from pets abandoned during the 1986 evacuation.
But in recent years, studies have shown that these dogs are genetically distinct from populations elsewhere in Ukraine.
In one 2023 study of 302 feral dogs, the researchers found there were remarkable differences between dogs living near the power plant and those living just 15km (9 miles) away.
That finding has fuelled a familiar narrative: radiation is causing rapid mutation. The reality is subtler. And stranger.
Rather than being driven by radiation, the changes reflect isolation. Small population size, limited movement, inbreeding, altered diets, disease exposure and human feeding patterns can all drive genetic divergence surprisingly quickly, even without radiation.
Chernobyl’s dogs show how fast populations can diverge when social and ecological conditions change abruptly, even when the animals themselves look entirely normal.
5. The ‘empty forest’
For years, one of the most unsettling ideas associated with Chernobyl was not what could be seen, but what wasn’t being heard.
In the years following the accident, researchers and visitors alike described parts of the exclusion zone, particularly the most heavily contaminated areas, as strangely quiet. Forests looked lush and intact, yet lacked the constant background noise typical of healthy ecosystems.
This gave rise to what ecologists sometimes called an ‘empty forest’ effect: landscapes that appeared structurally complex, but were missing some of their smallest, busiest layers of life.
At the time, that description made sense. Radiation levels were far higher in the late 1980s and 1990s, and ecosystems were dealing not only with contamination, but with abrupt human abandonment. Farming stopped. Forestry ceased. Habitats were thrown into flux almost overnight.
Normally, such ecological silence signals environmental collapse – yet here it existed alongside visible regrowth.
Four decades on, however, the soundscape has shifted once more.
Today, the exclusion zone is not uniformly quiet. In spring, many areas, including some still classified as highly contaminated, can be alive with birdsong.
Warblers, cuckoos and nightingales are present, sometimes in surprising numbers. According to Orizaola, the forest now often sounds far richer than first-time visitors expect.
That does not mean recovery has been simple or even. Some of the more contaminated areas still have localised declines in the number of insects. Similarly, bird communities are unevenly distributed around the region, shaped by the changing habitat and their insect prey.
What the empty forest idea captures, then, is not a permanent condition, but a moment in time. Chernobyl’s ecosystems have been changing for forty years. Silence was part of the story, but not the final chapter.
What Chernobyl really teaches us
This April marks 40 years since the disaster, but tidy conclusions about its impact on the surrounding landscape still fail.
Wildlife has returned largely because people left – but not evenly, and not predictably. Radiation continues to exert real biological pressure, often expressed subtly, unevenly and at small scales. Where adaptation occurs, it is rarely dramatic, and almost never straightforward.
As science writer Mary Mycio argues in her book Wormwood Forest, the exclusion zone is not a return to some pristine, pre-human past, but the emergence of a new ecosystem – shaped by contamination, abandonment and chance.
Chernobyl does not prove that radiation is safe. And it does not offer a blueprint for returning the urban sprawl to nature. What it shows is how ecosystems respond when the familiar rules break down – and how profoundly human absence, even when born of catastrophe, can reshape the living world.
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