Japanese macaque (snow monkey) juvenile yawning — in a very human-like manner — at the Jigokudani Monkey Park, in Nagano, Japan.

Let us take this opportunity to revisit a Japanese macaques (snow monkeys) post made last January, namely: zafoid.com/post/view/12272

That post featured some Japanese macaques (snow monkeys) enjoying a hot bath at a hot spring, at the same Jigokudani Monkey Park, in Nagano, Japan. However, it turns out that this world-famous practice of soaking in hot springs by the Japanese "snow monkeys", isn't actually an ancient survival instinct. Indeed, before 1963, no macaque had ever set foot in a hot spring!

The practice actually owes its origins at a traditional guesthouse in the Jigokudani valley, where staff and visitors had been leaving apples to feed the local monkey troop, when a bold young female macaque decided to venture into the guesthouse's outdoor onsen (hot spring) to retrieve an apple that had fallen into the water.

Whilst retrieving her food, she discovered that the warm water of the Japanese onsen offered a much comfortable relief from the biting winter cold. Soon, other juvenile monkeys began to copy her, and later the adults followed. Because wild primates sharing baths with human guests created hygiene and safety issues, the locals eventually built a separate, monkey-only hot spring nearby, in 1964 .... and this site evolved into the famous Jigokudani Monkey Park.

This bathing practice is a clear example of animal cultural transmission. The original macaques taught their offspring to bathe, and today, generations of snow monkeys who have never known a time before the baths, continue this endearing tradition. Scientists studying the Jigokudani monkey troop have analyzed their feces and confirmed that bathing significantly lowers their glucocorticoid (stress hormone) levels during the winter — it is indeed a highly effective coping mechanism against the winter cold. Yet, without human provisioning, a dropped apple, and a man-made stone pool, the famous snow monkeys would still be shivering in the trees!

Information source: www.quora.com/What-animal-behavior-first-thought-to-be-natural-is-later-discovered-to-be-the-result-of-interaction-with-humans/answer/NovaPrism-1