Japanese pigs live on after nuclear disaster

A decade after humans left territory surrounding the meltdown site of the Fukushima-Daiichi Nuclear Power Plant in Japan, pigs patrol the landscape. Scientists are now taking stock of the area’s new apex species.

“Once people were gone, the boar took over,” Fukushima University researcher Donovan Anderson told the BBC.

Anderson and his team studied the genetics of the boar that’s risen to dominate the irradiated area. According to the team’s research, published June 30 in the Proceedings of the Royal Society B, wild boar and abandoned domesticated pigs have interbred, creating a hybrid population unwary of human contact and seemingly impervious to radiation.

A devastating earthquake and tsunami in March 2011 led to a partial meltdown of Fukushima’s powerplant. The Japanese government evacuated roughly 150,000 residents from the 444-square-mile area because of the possibility of radiation poisoning. But that didn’t keep pigs from moving into areas previously occupied by humans.

Anderson’s team collected DNA samples from 191 boar from 2015 to 2018 to compare against genetic samples of wild boar taken before the accident. The researchers noted something unusual in the boar genome: The DNA samples showed evidence that local domesticated pigs had been folded into the wild boar population. According to the data, 16 percent of the boar tested proved to be hybrids, though that number appears to be diminishing over time.

“I think the pigs were not able to survive in the wild, but the boar thrived in the abandoned towns—because they’re so robust,” Anderson told the BBC.

Scientists have few examples of how plants and wildlife react to mass evacuation of humans. They have even fewer opportunities to research those evacuations when massive amounts of radiation are part of the scenario. After the 1986 nuclear disaster at Chernobyl, scientists studying the animals that remained in the irradiated region documented widespread mutations, deformities, and infertility.

According to the researchers at Fukushima University, the Japanese wild boar seems to be thriving in the abandoned towns and villages near the power plant. And despite being exposed to caesium-137 at levels considered 300-times the safe limit for humans, the boar seem to be reproducing just fine.