Let’s talk monkey business: his WHAT are blue?

Posted by Taylah Strauss on 26 January 2022

Vervet monkeys’ scientific name is Cercopithecus aethiops, which translates to ‘Ethiopian long-tailed monkey.’ Their tail is not their only distinguishing feature. Male vervet monkeys have…a rather colourful set of sexual organs.


Why so blue? Well, it’s rather complicated. Currently, there is not much understood about why vervet monkeys have blue testicles, though they are not the only primate to have these. Scientists do not believe it is blue due to sexual frustration or hormonal shifts, according to National Geographic.

Instead, scientists believe that it is likely blue due to the Tyndall effect; a scattering of light by the skin itself, not the presence of blue pigmentation in the skin. In essence, vervet monkeys have unusually organised collagen fibres, thus any slight change in those fibres, size, or distance could produce a different hue or colour.


Having a snack…Credit: Pexels

Vervet monkeys are largely vegetarian, with a diet consisting of leaves, seeds, nuts, grasses, fruits, berries and flowers. However, it is not unheard of them to feast on invertebrates, according to the South African National Biodiversity Institute.

Vervet monkeys have cheek pouches in which they store food, and they also have excellent colour vision which allows them to distinguish between ripe and unripe fruit.

They are also heavily reliant on water, and need a water source nearby.


Credit: Pexels

Vervet monkeys can live high up in mountain areas, but they do not live in rainforests or deserts. They prefer acacia woodland near to large water sources such as streams, rivers or lakes, according to the African Wildlife Foundation.


Credit: Pexels

These creatures are seasonal breeders, though mating season varies per geographical location. Female vervet monkeys reach sexual maturity at four years old, whereas males reach sexual maturity at around five years old.

Their gestational period ranges between 160 to 165 days. Typically, female vervet monkeys only carry one offspring per season.


Siblings having a tussle. Credit: Mike’s Birds/Flickr Commons

Vervet monkey society is composed of complex but stable social groups – troops – of 10 to 50 monkeys. They adhere to a strict hierarchical system, which controls feeding, mating, fighting, survival, and even grooming. In this hierarchy, dominant individuals get groomed the most.


Vervet monkeys are distributed throughout southern and east Africa, all the way down south to the Western Cape in South Africa.

Conservation Status

Due to the fact that they are so widespread in the continent, they are classed as Least Concern on the International Union for Conservation of Nature Red List of Threatened Species.

Picture: Alex Proimos/Flickr Commons


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