YAMANOUCHI, JAPAN - JANUARY 30:  Japanese Macaque monkeys relax in the hot spring at the Jigokudani (Hell's Valley) Monkey Park on January 30, 2010 in Yamanouchi, Japan. This Macaque troop regularly visits the Jigokudani-Onsen springs to escape the cold. This behaviour originates from a female Macaque who ventured into the hot springs to retrieve soybeans in 1963.  (Photo by Koichi Kamoshida/Getty Images)