Monkey Mania: The African monkey with no thumbs
Li Yunqi

At dawn, the frog-like calls of one of the most enchanting monkeys in Africa echo in the forests. These are the mantled guerezas that are also known as black-and-white colobus.

With a distictive face and a unique "hairstyle," these monkeys are already the stars in the forests of equatorial Africa. Moreover, their black and white "cowboy fringe jackets" add a streak of glamour to their nonchalant expressions.

The U-shaped white mantle on their back is the reason why they gained the name "mantled guereza."

The mantled guerezas are not born with this look. When a baby guereza is born, it's covered in white fur for the first few weeks, and that slowly darkens as it grows up. And its size grows from about 20 centimeters to around 60 centimeters in length.

Females only give birth to one baby almost every two years after a short pregnancy of about six months. They live in a group of up to 15 individuals. Mothers and daughters usually stay within the same group for their whole life while males would leave the group before they are fully mature.

These monkeys consume almost solely leaves. They spend most of the time chilling on trees, jumping between trees, and eating leaves. 

Unlike most primates, they only have four fingers and no thumbs. This is how the genus it belongs to – colobus – was named. It comes from the Greek kolobos, meaning "mutilated."

Some believe that the lack of a thumb may be an adaptation to allow for rapid movement through trees.

(Cover image designed by Li Yueyun.)

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