Suddenly, unexpectedly, I heard a sharp whistle radiating from the sky and gazed upwards. A huge horde of monkeys raced down a nearby slope towards us, bounding over rocks and skidding over gravel. I took a step back. Several minutes later, a man in Snow Monkey Park gear clambered after them.

I’d read online that the snow monkeys descend the mountain early each morning to relax in the onsen, and usually stick around until the afternoon. Clearly now was the time when they wanted to return back to their home, but there were paying tourists in the park, so the staff members weren’t letting them leave.

I felt uncomfortable as I watched them try to leave over and over again.

This site is pitched as a natural phenomenon, where monkeys happily bathe in hot springs and live their lives in calming harmony. The opposite, it turned out, was true. The monkeys at Jigokudani are essentially living in captivity, forced to spend their days around gawping humans rather than living in the onsen by choice.