Having had his morning coffee, Kenji Yoshikawa, a man with broad shoulders and a broad smile, puts on his skis and goes out to look for traces of wolf and lynx in the surrounding spruce forest. Running alongside him is Shiro, a watchdog that looks more like a cuddly polar bear.

Shiro has only had to warn Yoshikawa of predators a few times, and most traces of animal activity in the forest come from moose, but living in the Alaskan wilderness outside of Fairbanks, his reindeer are always potentially at risk. They are fenced in on the slope beneath Yoshikawa's cabin, a single room with a loft and no connection to power or water lines.

For three years Yoshikawa, 54, has been raising reindeer here, patiently trying to teach them to pull him in a sled.