Meet the fascinating monkey that turns blue when angry or excited

The changes are more prominent in males, whose “blueness” is directly related to their testosterone levels.

New Delhi | Updated: September 6, 2025 01:26 PM IST

2 min read

Mandrills are incredibly intelligent and live in large groups, that can sometimes be 800 members big (Source: Pixabay)

Do you remember the wise shaman and advisor, Rafiki, from The Lion King — the vibrant monkey with a red and blue snout, a flowy beard, and a walking stick? These are mandrills, among the most visually striking and incredibly intelligent primates on the planet.

While Disney was somewhat successful in capturing their colourful appearance, it forgot to portray one of their most unique habits: these monkeys turn blue when emotionally aroused, especially when angry.

Unlike the majority of their counterparts, who flush red when angry — thanks to blood rushing to the surface of their skin — mandrills have a special mechanism at play. While the blood rush is common, in the case of mandrills, it helps microscopic structures on their skin scatter light, leading to a bright blue appearance on their face and hindquarters.

The changes are more prominent in males, whose “blueness” is directly related to their testosterone levels. The bluer a mandrill gets, the stronger its build is considered.

Mandrills often use this trait to assert dominance, mark their territory, and fight off dangers. Since they are often found in large groups, sometimes as large as 800, their dominance plays a pivotal role in determining social rank—without resorting to physical violence.

This unique feature also has a sexual angle. Like other primates, mandrills consider strength one of the key traits when selecting and wooing mates. A male mandrill will display his brightest blue hues to attract a particular female.

While a brightly coloured mandrill is the alpha of the herd, less dominant males and females have duller tones, blending more easily into the forest surroundings.

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While many confuse mandrills for baboons, they are more closely related to drills. Even drills have distinct differences: a duller appearance, a black face, a smaller size, and compact groups.

Not just drills—mandrills are larger, more social, and far more colourful than any other monkey scientifically documented or studied. However, these majestic monkeys are currently listed as Vulnerable on the IUCN Red List due to rampant habitat loss and hunting.

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