Then, all at once, the subject is dropped, and we never hear of it again. Another topic slides in to take its place; oh, say, there’s a worldwide epidemic, or a war in Europe, or maybe the political scene becomes sensational, and we forget about yesterday’s scandal, last month’s heartbreak, last year’s catastrophe. But sometimes, for no particular reason, we ask ourselves: “Whatever happened to those radioactive feral pigs in Japan?”

It must have been something I heard about the depredations of feral pigs near Waco, Texas, that reminded me of the radioactive Japanese boars.

Background: March 11, 2011, a magnitude 9.1 earthquake, followed by a tsunami with an estimated maximum wave height of 130 feet, struck the northeast coast of Japan, killing more than 18,000 people across a wide stretch of the country’s eastern coast. Fukushima Daiichi Nuclear Power Station sustained three meltdowns and three hydrogen explosions releasing radioactive materials into the atmosphere. More than 160,000 residents of Fukushima were evacuated.

Wildlife, including boars, far from showing any obvious ill effects from the radioactive poisoned land, began to thrive around Fukushima after the meltdown. The boars multiplied rapidly, breeding with pigs from abandoned local farmyards, and ran rampant in the ghost towns. Scientists refer to domestic pigs who diversified the wild pig gene pool as “invaders,” which I feel is harsh.

To see firsthand what is happening in Fukushima 14 years after the nuclear disaster, you might want to look into “Japan’s Fukushima Hope Tour 2025, with licensed guide and vehicle.” The tour is designed to be educational for both local people and international visitors, showing the extensive damage as well as major decontamination work in the area. (The radiation evacuation zone is shrinking but will remain limited for at least 30 years.)

Since 2018, people have started to move back into previously abandoned areas near Fukushima.

The New York Times story, “Thousands of Radioactive Boars in Fukushima Thwart Residents’ Plans to Return” was sent to me by my sister, Molly.

“Cheer up! Think you have problems? You could be thwarted from returning home by toxic wild boars,” she said.

I forwarded the story to a friend in Texas and she told me that yes, she and her neighbors have problems with feral hogs, but at least they are not radioactive.

Since the nuclear catastrophe and evacuation, rats have taken over Fukushima supermarkets, no doubt patiently awaiting the next food delivery. Wild boars, civets and macaque monkeys have settled into the houses of evacuees, the boars reportedly becoming quite territorial, even vicious. The area has become a kind of hog heaven.

“Once people were gone, the boar took over,” explained Donovan Anderson, a researcher at Fukushima University in Japan. “In case of the invasive species — pigs that were released from the event — we think they had poor adaptation or survival characteristics in the wild. Theoretically, increased genetic diversity from pigs could help these boars combat swine fever and other diseases, but that doesn’t seem to be the case with these boar-pig hybrids.”

Pig genes discovered by scientists in pig-boar hybrids were diluted across successive generations.

According to Anderson, pigs didn’t adapt well to the natural environment, while the boars did very well in the evacuated towns and farmlands without the pressures of human presence.

Animal control hunters have been shooting and killing wild boars in an effort to make the area safe for returning humans. The meat from the wild boars is still considered too radioactive to eat by Japanese government standards.

University of Georgia researcher James Beasley, who has been studying the effects of the nuclear disaster on the area’s wildlife since 2015, agreed that wildlife species in the radioactive zone have tended to move from forested areas and nearby hills into the abandoned towns and villages.

“That’s creating a major human-wildlife conflict issue, particularly in areas that have been remediated and people are beginning to repopulate,” he said.

Always there to offer sound online advice, “Quora” suggests the following tips for “What to do if you see a wild boar in Japan:”

Remain calm. Avoid sudden movements. Do not approach the wild boar. Do not corner the animal. Retreat slowly, walking backward.

A wild boar can run 30 miles per hour!

Have a good week.