Spa therapy isn’t just for humans and dogs. A new study has found that monkeys also benefit from some hydrotherapy.
Researchers led by Rafaela Takeshita at Kyoto University in Japan found that female Japanese macaques bathe in hot springs to lower stress.
According to the University website, Japanese macaques, also known as snow monkeys, have been enjoying baths in the hot spring at Japan’s Jigokudani Monkey Park for years – and have become a popular tourist attraction. The study is the first to find evidence to scientifically validate the benefits of this behaviour.
Japanese macaques are the most northerly species of nonhuman primates in the world, and have adapted to extremely cold winters. Researchers believed that those living in the Jigokudani Monkey Park in Nagano maintain their normal body temperature due to having thicker and longer fur during winter. These primates are also the only group of monkeys known to take hot spring baths, a behaviour that was first observed in 1963 when a young female was seen in an outdoor hot spring belonging to a nearby hotel one snowy day. Other monkeys soon copied this behaviour, and for hygienic purposes, the park management has since built a hot spring for the exclusive use of the monkeys. By 2003, one in every three females in the group bathed regularly in winter.
Takeshita and her colleagues studied the bathing habits of twelve adult females during warmer and colder weather. The researchers collected fecal samples during times of extreme cold and analyzed the concentration of fecal glucocorticoid (fGC) metabolite present. Thermoregulatory stress and the management of body temperature is known to influence concentrations of glucocorticoids.
The results confirmed that the monkeys use the hot spring more often in winter than in spring, and especially during colder weeks, and that taking a spa reduced stress hormone levels.
The findings indicates that the hot spring has a stress-reducing effect in snow monkeys, said Takeshita.
Takeshita and her colleagues also reportedly found that the around 500 visitors per day, who watch the snow monkeys bathe, had no effect on the monkeys’ levels of stress hormones. (Research has yet to be done on stress reactions in humans when there are 500 people watching them bathe.)