Humans have it quite easy. If they do not wish to be bothered, they either verbalize it, or better still, place a 'do not disturb' sign outside their rooms - But what's a poor monkey to do when it wants to be left alone?

Just ask Milly the mandrill monkey that resides at England's Colchester Zoo - She just covers her eyes with her hands when she needs some space - And, its seems as if other members of her clan have not only figured out what she means, but also, adopted the same technique themselves.

Milly, the only female among the 23-member strong community that resides at the Zoo first began using the gesture, when she was just three years old. While the Zookeepers noticed it, they assumed she was simply shielding her eyes from the sun.

It was not until Mark Laidre visited the Zoo in 2007, that Milly's simple gesture received any credence. Having observed mandrills in the wild for over five years, the California-based evolution biologist was convinced that the monkey was trying to convey something.

During his 100 hours of observing the behavior of the zoo monkeys he noticed that when any member of the clan loosely placed their hands over the eyes, they were not approached or touched by the other monkeys as much. The sign also seemed to work as a plea by monkeys that were being 'bullied' by some of the stronger members of the clan.

Since Mandrill monkeys are not known to imitate humans in the same way apes do, the researcher is sure that Milly did not pick the habit up from a visitor or zoo worker. Also, this kind of gesture has never been seen in the wild or at any other zoo, which leads Mark to conclude that the smart monkey came up with it, all on her own.

Mark believes that when Milly first performed the gesture, it's possible that she believed it hid her from the rest of the clan. When she reacted negatively at being touched, an association was possibly built between the gesture and the reaction, which is how it evolved into the 'do not disturb' sign. Pretty amazing - We wonder what other signs the smart monkey has come up with!

Mandrills, the largest member of the monkey species are also, the most colorful, with the face often sporting a red stripe in the center and blue ridges on the sides. They also have red nostrils and lips and yellow beards. Native to the Equatorial forests of Congo, Gabon, Cameroon and Equatorial Guinea, the omnivores are closely related to baboons and drills.

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