Animal behaviour: How did the Fukushima disaster affect pet dogs?

A comparison of the behaviour and levels of the stress hormone cortisol in dogs abandoned after the Fukushima nuclear accident in 2011 and those abandoned in another region of Japan is published in the journal Scientific Reports. The behavioural and endocrine responses of dogs from the Fukushima region suggest they underwent a period of extreme stress, which persisted even after resocialization training and care.

The Tohoku earthquake of 11 March 2011 and subsequent nuclear incident has left around 340,000 Japanese people living as refugees. The accident and prolonged refugee situation has also led to the unintentional abandonment of many pets. Students at the University of Azabu have been conducting a program to place dogs from a rescue centre in Kanagawa with new owners, after the provision of psychosomatic care in a training facility. In 2011, these services were also provided for disaster-affected dogs from Fukushima.

During resocialization training, Miho Nagasawa, Kazutaka Mogi and Takefumi Kikusui assessed the dogs’ behavioural characteristics and urine cortisol levels. They found that compared to dogs from Kanagawa, the Fukushima dogs showed significantly lower levels of aggression towards unfamiliar people, lower trainability and lower attachment to carers. The urine cortisol levels of the Fukushima dogs were also five to ten times higher, a trend which persisted even after 10 weeks, suggesting the disaster had a prolonged impact on these animals.

As the study was based on a limited number of samples, it was difficult to eliminate factors other than the experience of the disaster in Fukushima, the authors caution. The Fukushima dogs were relatively older than the others, for example, although the authors found no age-related effects, suggesting the dogs’ experience after the disaster was the most significant factor. Further research is needed into the long-term impacts of disasters on pets, the authors conclude.