Yuki, age unknown, was discovered wandering in the Fukushima, Japan, area… (Takefumi Kikusui )
She was found roaming the streets of Fukushima's exclusion zone, the sprawling ghost town that now surrounds Japan's quake-crippled nuclear reactor.
One of an unknown number of dogs that were left chained or abandoned amid the disaster, the haggard-looking mutt bore a scar over one ear and unmistakable signs of chronic stress.
Yuki, as they called her, seemed to be suffering from a canine form of post-traumatic stress disorder.
While some 340,000 people still live as refugees in the wake of the March 11, 2011, earthquake and tsunami, animal science researchers at Azabu University report that former pets have also suffered lingering effects.
In a paper published Thursday in Scientific Reports, lead author and veterinary scientist Miho Nagasawa wrote that stray and abandoned animals recovered near the Fukushima Dai-ichi power station had stress hormone levels far higher than other Japanese dogs.
They also showed greater difficulty learning and developing an attachment to people.
Even after the dogs received care and re-socialization training, the effects of extreme stress persisted.
"The dogs from Fukushima showed significantly lower aggression toward unfamiliar people, trainability and attachment to their caretakers," Nagasawa and colleagues wrote. "Also, urine cortisol levels in the dogs from Fukushima were 5-10 fold higher than those in abandoned dogs from another area of Japan."
Nagasawa, who studies animal cognition and endocrine response, said the analysis involved an admittedly small number of dogs: 17
Those dogs, along with strays collected from another part of Japan, Kanagawa, were placed in a special dog rescue program at Azabu University. The animals were then cared for and trained so that they could be placed with new adoptive families.
Study authors said that cortisol levels in the Fukushima dogs remained much higher than those of the Kanagawa dogs even after 10 weeks of care.
They wrote that impaired learning and an inability to bond with people were also experienced by humans with PTSD.
"Humans affected by the disaster are already recovering and gradually returning to normal life," the study authors wrote. "However, our results suggest the possibility that stress can induce excessive, deep psychosomatic impacts ... in dogs. Long-term care and concern regarding the psychological impacts of disasters appears necessary in humans and companion animals."