THE ANIMAL FILES

Japanese macaque

Macaca fuscata

A troop can inherit habits as well as share a home range.

Japanese macaques live in social groups built around female family lines. Their familiar snowy portraits show only one setting: their foods and learned habits differ among places and seasons. Watching who learns from whom can be as revealing as watching what a monkey eats.[1]

Follow the evidence ↓
Japanese macaque
Image: KENPEI · Commons · CC BY-SA 3.0
Social links
Female relatives remain in their natal group[1]
Contact calls
Coos are exchanged during feeding and movement[1]
Diet
Plant foods and invertebrates, varying seasonally[1]

Families and grooming partners

Females generally remain in their natal group, while males leave and may join several groups during their lives. Related females groom each other frequently, but grooming also links unrelated individuals. These interactions maintain social relationships as well as clean fur. A troop contains several family lines rather than one mother and all her descendants alone.[1]

Food washing with a local history

At Koshima, researchers provisioning sweet potatoes observed a female called Imo washing them in water. Other troop members subsequently adopted the behaviour, and it persisted across generations. This is an account of behaviour spreading within a studied group, not evidence that all macaques everywhere suddenly acquired the habit. The famous “hundredth monkey” retelling distorts that distinction.[1]

Seasonal menus and contact

Fruit, leaves, seeds, fungi and invertebrates all occur in the diet. The balance varies geographically and seasonally; on Yakushima, summer fruit and winter herbs have different importance. During feeding or travel, coo calls are often answered by other monkeys. These exchanges are thought to help maintain contact within a moving group.[1]

A COMMON MIX-UP

Did every Japanese macaque learn potato washing at the same time?

No. The documented account concerns learning and transmission in a particular provisioned troop.[1]

TRY A LITTLE REASONING

What evidence would distinguish a local learned habit from a species-wide instinct?

Reveal the explanation

Track its appearance in identified individuals and its spread through their social contacts, then compare other groups. The Koshima observations provide that local sequence.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Macaca fuscata (adapted and translated; exact revision)
  2. NCBI Taxonomy — Macaca fuscata (identity and game lineage)

Last fact check:

One discovery leads to another

MandrillA bright face is a signal, not a permanent coat of paint.Mandrillus sphinx ↗Guinea baboonGround foraging and tree sleeping share one day.Papio papio ↗Western gorillaA large ape follows a changing fruit calendar.Gorilla gorilla ↗