THE ANIMAL FILES

Mandrill

Mandrillus sphinx

A bright face is a signal, not a permanent coat of paint.

Adult male mandrills have especially vivid facial colours, while females are smaller and generally less colourful. Fruit and seeds form much of the diet. Studies of males connect redness with social rank changes over months.[1][3][4]

Follow the evidence ↓
Mandrill
Image: ((brian)) from Sebastopol, CA, USA · Commons · CC BY 2.0
Facial appearance
Red and blue are especially conspicuous in adult males[3]
Food
Fruit, seeds and varied additional foods[1]
Cheek pouches
Can store food for later processing[3]

Colour needs an individual context

Adult males have conspicuous red facial areas and blue or purple ridges. Females are smaller and generally less vividly coloured.[3]

Forest food comes in several forms

Plants make up the core of the diet, including fruits, seeds, leaves and pith, but invertebrates and other animal foods are also recorded. Seasonal resources alter where food is sought.[1]

A signal can change without being instantaneous

Durham researchers report that male redness changes with social rank, but the documented changes develop over months rather than appearing instantly. A signal can therefore be dynamic while still requiring a suitable timescale for observation.[4]

A COMMON MIX-UP

Is every colour change an immediate mood switch?

No. The rank-associated changes described by the Durham research developed over months. A relationship between appearance and social conditions does not mean that every visible difference is a rapid emotional reaction or that one photograph proves its cause.[4]

TRY A LITTLE REASONING

Why compare a known individual rather than unrelated portraits?

Reveal the explanation

Differences between animals can involve sex, age and individual variation. Following one animal over time better separates change within an individual from differences that were already present between separate mandrills.[1][4]

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 — Mandrill (fixed revision; adapted and translated)
  2. NCBI Taxonomy — Mandrillus sphinx (identity and classification)
  3. San Diego Zoo Wildlife Alliance — Mandrill
  4. Durham University — Mandrill research: male ornaments

Last fact check:

One discovery leads to another

Japanese macaqueA troop can inherit habits as well as share a home range.Macaca fuscata ↗Guinea baboonGround foraging and tree sleeping share one day.Papio papio ↗Western gorillaA large ape follows a changing fruit calendar.Gorilla gorilla ↗