Japanese macaques, a species of monkey inhabiting Japan, reduce their stress levels in winter by bathing in onsen hot springs to warm their bodies, according to an academic report by a research team.
The report, which was made by a team including researchers from Kyoto University's Primate Research Institute in Inuyama, was published in an online journal for the Japan Monkey Centre, also in Inuyama.
The study tracked 12 female Japanese macaques at the Jigokudani Yaen-koen monkey park in Yamanouchi, which has an onsen spa exclusively for the monkeys.
In 2014, the researchers collected fecal samples from the monkeys in spring (April to June) and winter (October to December) and measured levels of the hormone cortisol. High levels are said to indicate high levels of stress.
According to the researchers' findings, the monkeys' cortisol levels were about 20 per cent lower when they bathed. In contrast, their cortisol levels were about the same in spring regardless of whether or not they bathed.
