Japanese macaques, also known as snow monkeys, play as they soak in a hot spring in Jigokudani valley in Nagano Prefecture, northwest of Tokyo Saturday, March 6, 2021. (Photo by Kiichiro Sato/AP Photo)

A young macaque perches on a pole, observing nearby tourists while eating some seeds in Jigokudani Yaen-koen wild macaque monkey park on February 16, 2015 in Yamanouchi, Nagano, Japan. (Photo by Manuel Romaris/Getty Images)

“Mother and Child”. Snow monkey at “Jigokudani hot-spring” in Nagano, Japan. (Photo by Kiyoshi Ookawa)

“A Little Monkey on the Cliff”. “A cold front hit the Nagano prefecture. I saw a little monkey enduring the cold in Jigokudani Monkey Park. This little monkey is really cute”. (Photo by Hidetoshi Ogata/Smithsonian Photo Contest)

Japan Self-Defense Force (JSDF) soldiers and firefighters make rescue works among mountain lodges, covered with volcanic ash near the peak of Mt. Ontake, which straddles Nagano and Gifu prefectures in this September 28, 2014 photo taken and released by Kyodo. More than 30 people were feared dead on Sunday near the peak of the Japanese volcano that erupted a day earlier, sending a huge cloud of ash and rock tumbling down its slopes, while packed with hikers. (Photo by Reuters/Kyodo News)

Macaques huddle together for warmth at a hot spring in Nagano, Japan in the last decade of December 2023. Known as snow monkeys, the animals soak in the 40°C water every day during cold weather, spending their bathtime grooming, snoozing and playing on visitors’ camera tripods. (Photo by David Lazar/Animal News Agency)

“Can't wait”. Location: Inao Station (JR Oito-Line), Nagano Prefecture, Japan. (Photo by AZURE)

Japanese macaque monkeys enjoy sitting in the hot springs at Jigokudani-Onsen (Hell Valley) on January 23, 2005 in Jigokudani, Nagano-Prefecture, Japan. Japanese Macaques, also known as snow monkeys are the most northerly nonhuman primate in the world. In 1963 a female Macaque ventured into the hot springs to retrieve some soybeans. This behaviour was adopted by other monkeys, and eventually by the entire troop. This Macaque troop regularly visits the Jigokudani-Onsen springs to escape the cold. The hot springs are said to help relieve nerve pain and fatigue. (Photo by Koichi Kamoshida/Getty Images)