Monkeys at Colchester Zoo have invented a unique do not disturb sign that has amazed experts.
The mandrills - the largest member of the monkey family - put their hands over their eyes when they want to be left alone.
Its a gesture thats never been seen before, and experts believe its evidence of social culture among animals. They believe one of the mandrills made up the gesture and passed it on to her pals something thats common in humans but almost unheard of in animals.
No other monkeys use the gesture, says Mark E. Laidre, an evolutionary biologist at the University of California, Berkeley, USA, who reports on the mandrills in the Scientific American magazine. Its not to block the sun, and their eyes remain open.
1n 1999, zookeepers saw a young female mandrill, Milly, make the gesture, but it was only when Laidre visited in 2007 that anyone realised itys significance
Hed been observing mandrills in Africa, Europe and North America for more than five years.
"I saw this behaviour in the first few hours," he said. "I'd never seen this before; I knew it was very interesting. By covering their eyes with their hands, individuals possibly conveyed to others that they wanted to be left alone, and this message may have been respected as a 'do not disturb' sign."
He found that mandrills who covered their eyes gesture were generally left alone not approached or touched - by their peers.
It is believed the signal was first used by Milly and she has passed it on. (more)