The Jigokudani Yaenkoen park opened in 1964 and since then many thousands of people from around the world have visited the park to observe the lifestyle of the Japanese Macaque. The Japanese Macaque (Macaca fuscata) is a monkey species native to northern Japan, and is the most northern-living non-human primate, surviving winter temperatures of below -15 °C. They have brown-gray fur, a red face, hands and bottom, and a short tail – and often seem remarkably human like.In the wild they spend most of their time in forests and feed on seeds, buds, fruit, invertebrates, berries, leaves, and bark. The monkeys have a body length ranging from 80 to 95 cm. The males weigh around 10-14 kg while the females are usually around 5.5 kg.