Capuchin monkeys use sticks to pick their NOSE: Primate captured on video using a tool to groom herself

It is seen as a rather dirty habit in human societies, but it appears some monkeys have found a more hygienic way of picking their nose.

Researchers have reported seeing a wild female bearded capuchin monkey using a stick to root around in one of her nostrils.

They say it one of the more unusual examples of tool use among primates.

Male bearded capuchin monkeys, for example, are known to use sticks to coax small lizards out from under rocks and chimpanzees use sticks to 'fish' for termites. 

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A wild female capuchin monkey called Acacia was spotted by researchers using a stick to pick her nose (pictured). After putting it up her nose, the capuchin would then inspect and lick the stick. It is one of the more unusual forms of tool use seen in the monkeys and is particularly rare as females do not appear to use tools

However, biologists at the University of Oxford were surprised when they noticed a female named Acacia carefully sliding a small stick up her nostril while watching a group of capuchins at Serra da Capivara National Park in Brazil. 

They say she tried several different sticks and even a piece of grass, checking them each time she withdrew them before giving them a lick.

The behaviour repeatedly caused the female monkey to sneeze.

Researchers say she may have been trying to dislodge something caught in her nostril or perhaps to relieve an irritating tickle.

However, Dr Michael Haslam, a primatologist at the University of Oxford who led the research, said it may be the female was just curious.

He said: 'I was actually watching a different capuchin that was using stone tools and I could hear tiny monkey sneezes coming from nearby, but it wasn't until I looked up from my camera that I realised there was an adult female using sticks and grass to make herself sneeze. 

'I was extremely surprised, because even after years of study by my co-author Tiago Falotico, the use of stick tools for any purpose was almost an entirely male capuchin activity. 

'And here was a female, casually and very carefully putting a stick up her nose over and over again. 

'She was concentrating very hard on the job, and she usually only stopped once she'd triggered a sneeze. 

'The male capuchins don't use sticks on themselves, they usually use them to poke at prey such as lizards, which hide in rock crevices.' 

The researchers, whose work is published in the journal Primates, also report the female using sticks to prod at her teeth and gums like a toothpick.

They say this may have been to relieve discomfort or dislodge an irritating piece of food that had become lodged there.

Dr Haslam said: 'I don't know the motivation for Acacia's sneeze stick, or tooth picking. 

'She was relaxed at the time, and was being groomed by an adult male capuchin, so it may be she was simply experimenting. 

'The monkeys often pick up sticks and other objects to chew on, so it's not uncommon to see them holding all kinds of plant parts, but the care that Acacia took was very obvious - it wasn't an accident.'

After putting the sticks and blades of grass up her nose, Acacia (shown above) would inspect the stick. She did this repeatedly, taking great care with the stick but making herself sneeze in the process

They said the behaviour is particularly unusual as female capuchin monkeys have almost never been seen using tools before.

Among male capuchins they will often use sticks to pick under rocks to flush out lizards and to dig up food. They also use stones to break open hard fruit and nuts.

Writing in the journal, Dr Haslam and his colleague Tiago Falotico said: 'Intriguingly, use of probe tools is almost exclusively practiced by male capuchins.

'No adult female has been seen to use a probe tool for foraging, and the only prior instance of an adult female using a stick tool was when one capuchin used a stick to poke the individual she was grooming.

Acacia would put the stick in her mouth and lick it after putting it up her nose. The researcher say it is not clear why she was using the stick in this way but she was clearly concentrating hard on her task

'This report therefore demonstrates that the observed sexual bias does not result from any impediment to such actions in wild adult females.

'We do note, however, that the female probe tool use was selfdirected, whereas foraging probes appear to be used exclusively by males.

'Another difference is that Acacia never modified the tool prior to or during its use, while probe use by males involves modification most of the time.'

The only other example of a primate using a stick to pick its nose was in a male chimpanzee living in East Africa that used sticks to clear his nose, including when he was suffering from flu.

Long tailed macaques in Lopburi in Thailand are also known to pull hair from women visiting a shrine there to use like dental floss.