Bizarre Japanese hibernation story

Here's another bizarre Japanese story that seems to have made more of a splash abroad than in the Japanese press. A walker went missing on a mountain side, and was found 3 weeks later apparently in a state of hibernation. I have seen some bizarre stories of unusually long-term survival in extreme cold (like this famous baby, and the mammalian diving reflex enabling people to stay alive under water for lengthy periods), but this "hibernation" seems rather different. However, this version of the story in the Japanese press is rather less extravagant in tone.

In any case, now he's out of hospital and apparently fully recovered, no doubt he'll be putting in plenty of overtime to make up for his lengthy absence!