Monkey Signs, Monkey Rules, Monkey Reality

Japan Trip Series, Part 5

​After the initial “wow” settles, Arashiyama Monkey Park turns into more of an educational excursion. Throughout the park, there are signs full of facts about the monkeys.

​First: What these monkeys are. The park identifies them as Japanese monkeys (Macaca fuscata), an endemic species in Japan. They’re also described as “snow monkeys”, and the signs note they live in the northernmost monkey habitat in the world. 

​Then there’s the park’s relationship with the troop. Since the park was established at Iwatayama, staff have been feeding wild monkeys so they stay in the area and can be observed. The signs also note that, generally, there are about 30–50 monkeys in a group in the wild, and in this park you can find around 120 monkeys. 

Some of the most memorable facts were the physical ones:

• Adult Weights: Adult males are about 12–15 kg, adult females about 8–10 kg.
• Newborn Weight: About 500 grams at birth.
• Growth: They stop growing around the tenth year of their lives. 

​Those numbers quietly recalibrate how you see them. They’re not tiny. They’re not pets. They’re compact, muscular, fast, and fully built for their environment.

The signs also explain their life cycle and seasonal rhythms:

• Birth Period: April to July.
• Bleeding Season: October to February. During this time, their faces and buttocks are red, and become redder than usual.
• Pregnancy: About 6 months, and twins are very rare.
• Adulthood: About 10 years.
• Lifespan: About 30 years. 

​Diet-wise, the park describes them as omnivores, but specifically notes they don’t catch other mammals to eat. They like fruit and leaves, and eat insects in summer. It is also noted other wild animals share their habitat, including deer, birds, and boars. 

​One of my favourite signs was about facial expressions (both fascinating and useful). It explains that monkeys communicate with facial expressions and voice, and gives a simple distinction: If you can see an upper tooth, it’s afraid; if you can’t see an upper tooth, it’s angry. 

That pairs neatly with the park’s core rules for visitors:

• Don’t stare into their eyes.
• Don’t touch them.
• Don’t show them food or feed them outside designated areas. 

​Taken together, the signs made the experience safer and more meaningful.

​​I love learning about monkeys. 

And from that hilltop, with Kyoto spread out below and a troop of Macaca fuscata doing what they’ve always done—yeah. That’s a good day.

Note: All photos and videos in this post were taken by me with an iPhone 17 Pro.