The world is awesome: macaque edition

They say necessity is the mother of invention.

For the Japanese Macaques, it was more like luck.

In 1963, a young female monkey named Mukubili waded into the hot springs in Nagano, Japan, after a soy bean had fallen in the water.

Once in the steamy hot tub, she figured she'd give it a few before returning to the cold mountain air, with temperatures that can drop as low as 5 degrees Farenheit, according to the New England Primate Conservancy.

Call her crazy, but she was onto something. It didn't take long before other macaques, also known as snow monkeys, took notice and joined in the fun.

Today, the macaques in northern Japan spend basically all their time in the hot tubs, as these photos show.

A Japanese macaque and her infant bathe in the hot springs at Jigokudani-Onsen (Hell Valley) in Jigokudani, Nagano, Japan. (Koichi Kamoshida/Getty Images)

(Koichi Kamoshida/Getty Images)

About 160 macaques live around Jigokudani Monkey Park. They are a popular tourist draw. (Kazuhiro Nogi/AFP/Getty Images)

Decades ago it was thought that humans were the only primates who could benefit from learned behavior. All that changed in the 1950s, when researchers encountered a brilliant snow monkey named Imo.

Imo wasn't yet 2 years old in 1953, when researchers tried to lure her and her fellow macaques out of the forest by laying out food on the ground. Most of the monkeys brushed off the sand, but Imo, according to National Geographic, thought it would be a better idea to dunk the yam in the water to wash it clean. When she took a bite, she decided she liked the salty coat the water had left — and a star was born.

Imo passed the behavior to her mother and a decade later about three-quarters of the Koshima troop of monkeys over the age of 2 wash their food.

The hot springs are said to help relieve nerve pain and fatigue.(Koichi Kamoshida/Getty Images)

(Koichi Kamoshida/Getty Images)

(Koichi Kamoshida/Getty Images)

(Kazuhiro Nogi/AFP/Getty Images)

(Koichi Kamoshida/Getty Images)