eep in the Yokoyu River valley in northern Nagano, at 850m, steam rises from the cliffs of a gorge known for centuries as Jigokudani, or "Hell's Valley." Snow covers it for nearly a third of the year, and winter nights fall below −10℃.
A troop of wild Japanese macaques lives here. They have been watched up close since the park opened in 1964. The habit of bathing began by chance: a young monkey climbed into a nearby inn's outdoor bath, and the others slowly followed. The park later built the monkeys an onsen of their own, and the habit has been passed down ever since.
On the day I visited, snow kept falling. Some monkeys dozed in the steaming water, frost on their fur. Others sat on the snow with their little ones close beside them. To reach them, you walk a 1.6km forest trail, about 25 minutes from Kanbayashi Onsen.
长野县北部的横湯川溪谷，海拔 850m。陡峭的崖壁间温泉终年冒着白烟，人们从很久以前就把这里叫作「地狱谷」。一年里将近三分之一的时间被雪覆盖，冬天最低气温会低于 -10℃。
这里生活着一群野生日本猕猴。1964 年开园以来，人们一直可以在这里近距离观察它们。猴子泡温泉原本只是个偶然：一只小猴学会了钻进附近旅馆的露天温泉，其他猴子也慢慢跟着学。后来园方给猴子修了专用温泉，这个习惯就一代代传了下来。
我去的那天雪一直在下。有的猴子泡在热气里打盹，毛上落满了雪，有的抱着小猴蹲在雪地里。从上林温泉沿林间步道走 1.6km，大约 25 分钟就能见到它们。
