It was in the early 1960s that the Japanese macaques of upper Yokoyu Valley first discovered the joys of basking in thermal pools to alleviate the rigours of winter. Alas, their droppings did little for business, so the local hoteliers built a special onsen for them at Jigokudani, where a troupe of over 200 have now become the area’s principal visitor attraction.

The pink-faced monkeys live at a more northerly latitude than any other non-human primate. Their yellowish, grey-brown fur is well-adapted to the conditions, but even so, life can be harsh for them in winter – hence their love of hot-water bathing. Watching the macaques go about their daily lives is the real highlight of visits to Jigokudani. Juveniles hang upside down from tree branches, play chase and leap joyfully into the hot water, while their older relatives soak in the pool, peering wistfully into space or closing their eyes as the mayhem unfolds around them.