The Japanese Macaque (Macaca fuscata), is a terrestrial monkey species native to Japan. It is also sometimes known as the ”Snow Monkey” because it lives in areas where snow covers the ground for months each year — no primate, with the exception of humans, is more northern-living, nor lives in a colder climate. It is found on three of the four main Japanese islands: Honshu, Shikoku and Kyushu. The total population of Japanese Macaques has been estimated to be around 114,000.
Jigokudani Monkey Park is part of the Shigakogen National Park, and is located in the valley of the Yokoyu-River. The name Jigokudani, meaning "Hell's Valley", is due to the steam and boiling water that bubbles out of small crevices in the frozen ground, surrounded by steep cliffs and formidably cold and hostile forests.
The heavy snowfalls (snow covers the ground for 4 months a year), an elevation of 850 metres, and being only accessible via a narrow two kilometre footpath through the forest, keep it uncrowded despite being relatively well-known. It is famous for its large population of wild Snow Monkeys, that go to the valley during the winter, foraging elsewhere in the national park during the warmer months. Starting in 1963, the monkeys descend from the steep cliffs and forest to sit in the warm waters of the onsen (hotsprings), and return to the security of the forests in the evenings.