#75 サルへの感情とわんぱく夏休みの話
Gakken's Zukan LIVE (図鑑ライブ) editor-in-chief Matsubara-san and editorial staff member Shoji-san, who studied primates in graduate school, walk through the primate section of the Animal Encyclopedia to cover distribution, classification, and standout species. Shoji-san reveals that his relationship with monkeys is not fondness but something more unsettling — they confuse him so thoroughly that he finds them frightening. The second half of the episode shifts to his Ehime travel diary: canyoning in Omogo Gorge and a visit to the Uwajima Ushioni Festival.
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What this episode answers
What characteristics define primates as a group, and where on Earth are they found?
Primates are defined by large, developed brains, forward-facing eyes, grasping forelimbs, and flat nails; they account for roughly 520 of the approximately 6,700 mammal species and are concentrated in equatorial and southern regions, with Aomori — habitat of the Japanese macaque — marking the world's northernmost limit.
How are primates broadly classified, and what distinctive species belong to each group?
Primates are divided into two groups by the internal structure of the nose: the Strepsirrhini (lemurs, aye-ayes, and other curved-nose species common in Madagascar) and the Haplorhini (Japanese macaques, capuchins, gorillas, and other straight-nose species). The tufted capuchin, depicted in the Nazca Lines, is clever enough to play claw-machine games.
Why does Shoji-san, who researched monkeys in graduate school, say he doesn't actually like them?
Shoji-san's motivation was not 'I like them, so I want to learn more' but 'they baffle me so completely that I have to understand them'; he says that meeting monkeys at the zoo makes him feel not 'cute' but something closer to a formal, deferential greeting — 'How do you do, I'm in your debt.'
What was canyoning in Omogo Gorge like?
Shoji-san went one-on-one with an instructor in Omogo Gorge near the headwaters of the Niyodo River, climbing rocks, jumping off waterfalls, and letting the current carry him; the river was slightly swollen from the previous day's rain but stayed within safe limits, and despite ending up with whiplash all over his body he called it an absolute blast.
What is the Uwajima Ushioni Festival, and what are the theories about the origin of the ushioni?
Held every July in the Nanyo region of Ehime Prefecture, the Ushioni Festival is a traditional performing art in which a massive ushioni (ox-demon) float covered in Canary palm fiber is carried through the streets; theories about its origin include a retainer who made an ushioni shape from red cloth to repel wild beasts, and a mechanism used by Sengoku warlord Kato Kiyomasa to intimidate enemies during the Korean campaigns.
What Are Primates? — A Group with Advanced Intelligence That Includes Humans
Matsubara-san brought in Gakken's Zukan LIVE (図鑑ライブ) Animal Encyclopedia, which opens its primate feature on page 58. The encyclopedia describes primates as "a group with large brains and developed intelligence," a description that gets a laugh from Matsubara-san: "Doesn't that make you want someone to say it about you?" The three defining features of the order are eyes positioned at the front of the face, forelimbs capable of grasping objects, and flat nails that do not damage what they grip. Humans are included in the order.
Of the roughly 6,700 mammal species, about 520 are primates. Their distribution clusters around and south of the equator — the Amazon basin of South America, Africa, India, and Southeast Asia are the main habitats. Populations thin out sharply toward higher latitudes, and Aomori, where the Japanese macaque lives, is cited as the world's northernmost limit. Shoji-san's most vivid memory from the Monkey Centre is watching a keeper use a blower to light a fire while the monkeys looked on without a trace of alarm — utterly calm, just observing. "It was like 2001: A Space Odyssey," he said.
Strepsirrhini and Haplorhini — Two Little-Known Divisions
"I genuinely had no idea," Shoji-san admitted when he first learned that primates are split into two groups based on the internal structure of the nose: the Strepsirrhini, whose nasal passages curve, and the Haplorhini, whose passages are straight.
The Strepsirrhini are represented by lemurs and aye-ayes — animals with long, fox- or dog-like snouts that look nothing like the "monkey face" most people picture. They are especially common in Madagascar. The Haplorhini are the monkeys and apes we know well: Japanese macaques, tufted capuchins, gorillas, and more.
The encyclopedia's species profiles cover considerable range. The **tufted capuchin** (フサオマキザル) lives in the Amazon basin and is depicted in the Nazca Lines; it uses stones as tools to crack nuts, is clever enough to play claw-machine games, and works as an assistance animal in Europe and North America — the species Shoji-san focused on in graduate school. The **common marmoset** (コモンマーモセット) has distinctive white tufts around its ears; Matsubara-san compared it to Doc from *Back to the Future*. The **Brazza's monkey** (ブラッツァグエノン), found from Ethiopia through central Africa and measuring 44–54 cm in body length, has an overwhelmingly elder-statesman face — Shoji-san said that locking eyes with one while lost in an African forest "would make you wet yourself." The **mandrill** (マンドリル) is famous for its vivid red, white, and blue face, a species Matsubara-san liked so much he sculpted one in clay as a student; despite the intimidating appearance it is a peaceable animal that avoids conflict, using its long fangs mainly to threaten. The gorilla's scientific name is *Gorilla gorilla* — genus and species identical. The orangutan is known as "the sage of the forest," and while chimpanzees are cute as children, Shoji-san warned that adults are "completely merciless."
Shoji-san's Complicated Feelings About Monkeys
"It's not that I like monkeys," Shoji-san said flatly. "The feeling isn't 'I like them, so I want to know more.' It's 'they baffle me so completely that I have to understand them.'" Matsubara-san said he feels the same way about snakes. At the zoo, facing a monkey, Shoji-san can never manage to think "cute" — instead he feels something closer to a stiff, formal greeting: *How do you do. I'm in your debt.* Creatures that look so close to human yet behave in ways that resist understanding — that uncanny valley was apparently what drove his research.
Ehime Trip Part 1 — Canyoning in Omogo Gorge
Taking his summer break in September to avoid the Obon crowds, Shoji-san spent three nights and four days in Ehime. One goal was canyoning — an activity similar to mountain-stream climbing where participants scramble up and get swept down canyon waterways. The location was Omogo Gorge (面河渓谷), near the headwaters of the Niyodo River in Kochi, a scenic spot where emerald-green water runs between rock formations. Matsubara-san was shown a photo of Shoji-san completely submerged.
He went one-on-one with an instructor: climbing rocks, jumping from waterfalls, riding the current. The river was slightly swollen from rain the day before but stayed within safe limits. Watching the video, Matsubara-san exclaimed, "Your head is just snapping back and forth" — the exertion left Shoji-san with full-body whiplash, but his verdict was an emphatic "so much fun." He recommends it to anyone who wants to get physical with nature.
Ehime Trip Part 2 — The Uwajima Ushioni Festival
The second goal was the Ushioni Festival (牛鬼祭り) in Uwajima. Held every July in the Nanyo region of Ehime, it is a traditional performing art in which enormous floats shaped like the ushioni (ox-demon) — covered in Canary palm fiber — are carried through the streets. Shoji-san described the silhouette as "like an alpaca": a slender neck rising from the body, topped with horns. Videos also show a smoke-breathing effect that he was especially eager to witness in person.
The exhibition facility he visited listed several theories about the ushioni's origin: one holds that a feudal lord's retainer fashioned the shape from red cloth to ward off a wild beast attack; another traces it to a mechanism Sengoku warlord Kato Kiyomasa used during the Korean campaigns to intimidate the enemy. Shoji-san couldn't make the July main festival due to work, but he took a commemorative photo with the giant ushioni on display and vowed to return for the real thing.
Takeaways
- Primates — roughly 520 species defined by forward-facing eyes, grasping hands, and flat nails — split into two groups by nose structure: the curved-nose Strepsirrhini (lemurs, aye-ayes; concentrated in Madagascar) and the straight-nose Haplorhini (capuchins, gorillas, and others), with the Japanese macaque's Aomori habitat marking the world's northernmost primate range.
- Shoji-san's motivation for studying monkeys was not affection but a compulsion born of confusion — they look nearly human yet behave in ways he cannot fully decode, leaving him with a feeling of formal unease rather than warmth when he meets them at the zoo.
- Shoji-san's Ehime trip combined intense physical adventure — full-body whiplash from canyoning in the emerald waters of Omogo Gorge — with cultural discovery at the Uwajima Ushioni Festival, whose giant ox-demon floats carry origins traced to either a retainer's ruse or Kato Kiyomasa's Korean campaign.
This article is edited from a machine transcript of the first 30 minutes of the episode. It is not an official summary — please listen to the episode itself.