Japanese macaques – also known as snow monkeys – live in areas where snow falls for months in Japan. Many of snow monkeys are preserved and protected by The Jigokudani Monkey Park, established in 1964. Outside the park, there is a local hotel which has a natural hot spring. People were surprised as a young female macaque taking outdoor hot spring at that nearby hotel. The reason may be she observed and curious about the spring. She mimicked human’s behavior and soon other monkeys mimicked her.
It was not until the first bathe of the female monkey that the park management had built a private spring for them. To do a deeper research, a team of researcher from Kyoto University followed 12 adult female monkeys during their spring birth season and winter mating season. They found out that monkeys’ levels of hormones were reduced. Dr Takeshita, the leader of the team, said: “The hot spring has a stress-reducing effect in snow monkeys. This indicates that, as in humans, the hot spring has a stress-reducing effect in snow monkeys”.
“This unique habit of hot spring bathing by snow monkeys illustrates how behavioural flexibility can help counter cold-climate stress, with likely implications for reproduction and survival,” added Dr Takeshita.
Now, The Jigokudani Monkey Park is in the must-visit list for tourists at Nagano, Japan. Although there are about 500 visitors each day, the monkeys’ stress hormone level were unaffected, according to Dr Takeshita.