A black fox is caught on camera in a mountainous part of Shari, Hokkaido. (Provided by Shiretoko Museum)

SHARI, Hokkaido--Experts identified a black fox in a video taken in this mountainous town in northeastern Hokkaido, but they could only guess at the origin of the extremely rare animal.

A motion-activating camera shot the video of the completely black Ezo red fox walking on a road around 3 p.m. on Sept. 23.

“At first, I thought it was a dog,” said Takahiro Murakami, 47, curator of the Shiretoko Museum, which set up the camera. “(But) I thought its tail was far too fluffy for a dog and found out later that it was a fox.

“It was the first black fox I have seen in my around 10-year career at the museum.”

Murakami said the rare color of the fox could be a result of a genetic mutation.

He also noted that black foxes were imported for their fur during the Taisho Era (1912-1926) and Showa Era (1926-1989) from Canada and elsewhere, and they may have become feral and passed down their genes.

Koji Uraguchi, 59, a senior medical zoology researcher at the Hokkaido Institute of Public Health, said there are several Ainu words referring to “black fox.”

“Black foxes could have existed (in Japan) since ancient times, but they are very rare,” Uraguchi said. “I have been observing foxes in the wild for about 30 years, and I have seen only two (black foxes) so far.”