Because of Japan’s high volcanic activity, thousands of hot springs are scattered throughout the country. Locally known as onsen, the mineral-rich water is believed to cure a wide range of ailments and diseases, from muscle pain to diabetes. Bathing in onsen has been a part of Japanese culture for centuries, and more recently it has been adopted by another population: the wild macaques of Nagano prefecture.
The town of Yamanouchi is covered in snow for a full third of the year, making it the perfect location for Japan’s largest ski resort and dozens of indoor and open-air baths. It was in one of these open-air onsen that a very young monkey first learned to take a bath. The warm water was welcoming in the cold weather and other monkeys in his troop soon began to copy his behaviour.