A graduate student from Texas had been standing in a restricted area for which he didn't have clearance when he was mauled by chimpanzees at a South African sanctuary.



The two male chimpanzees were likely wanting to mark their territory when they dragged Andrew Oberle, 26, under an electric fence then viciously attacked him on Thursday , said Eugene Cussons, director at the Jane Goodall Institute Chimpanzee Eden near Johannesburg, where the incident happened.



While he was giving a tour, Mr Oberle left the group and crossed one of two fences separating him from the animals into a 'no go zone', according to ABC News .

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Attack: Andrew Oberle, a University of Texas graduate student was savaged by two chimps while leading a group of tourists at the Jane Goodall Institute in South Africa

Animal lover: Oberle was subjected to hours of surgery following the attack, and suffered large cuts to his head and face that left his skull and facial bones exposed

The uncle of the University of Texas at San Antonio anthropology graduate student, Carl Oberle, said the man's parents were flying from the U.S. to visit their critically injured son.

He underwent six hours of surgery today, with doctors cleaning and stitching up his wounds.



The student suffered large cuts to his head and face and his skull and facial bones were exposed.



Doctors said Mr Oberle was in stable condition and induced sedation.

Carl Oberle described chimps as his nephew's 'passion' and said he knew each animal by its 'name and face.'

A conservationist who runs the sanctuary said investigators would have to wait until Mr Oberle was well enough to provide details to try to determine what prompted the attack.

The student was left fighting for his life after the alpha males, named Nikki and Amadeus, pounced on him at the South African reserve where he was studying their behaviour.

He was dragged along the ground for more than a mile by the animals.

The 26-year-old's mother said that her son had been passionate about chimps since watching a documentary about famous naturalist Jane Goodall in seventh grade.

Mary Flint added that her son knew the risks involved in working with apes, and said that the attack would probably not stop him carrying out further research.

In a case that mirrors that of Charla Nash, a Connecticut woman, who in 2009 had her face ripped off by a 200-pound chimp, Mr Oberle suffered a ‘frenzied’ attack, in which he was bitten multiple times.



The beasts grabbed him by his feet and yanked him down the road, under a fence and into their enclosure at the Jane Goodall Institute Chimp Eden where paramedics were forced to wait for armed escorts before they could go in and treat him.

Mr Oberle, an American researcher, was giving tourists a lecture at the sanctuary as part of his master's degree in Anthropology and Primatology, based at the University of Texas at San Antonio.



He had crossed the first of two fences separating the chimpanzees from visitors and was standing close to the second fence, which is electrified, when the attack began.



The tourists were escorted to safety by staff members as the chimpanzees dragged Mr Oberle out of their enclosure. The sanctuary's director fired shots into the air to scare the chimps away from the man, before chasing the animals back into their enclosure.



Brutal: Stacey Johns (right) a friend of Oberle's on Facebook, was hit in the head by a rock launched by Cozy (left). 'Cozy may hit people in the head with rocks but it's not his fault' Oberle wrote on the site



Calm before the storm: On Facebook these sleeping chimps (not the ones which attacked) are described by Oberle as 'cute'

One with the animals: In this undated photo Andrew Orbele poses one of his charges

Medics stabilised the graduate at the scene and he was taken by ambulance to a private hospital in Nelspruit. Beeld reported that he lost part of an ear and parts of his fingers.

'When we found him, he was in a foetal position underneath a lapa (a roofed, open-walled structure) with massive injuries, lacerations, abrasions, partial amputation from his head to toe,' Lloyd Krause, ER24 emergency service spokesman told the Herald Sun .

'He lost an ear, he lost a number of fingers and toes, he's got very deep wounds, he's got total removal of skin and muscle off his one leg and his one arm, fractures all over the place.'

On Mr Oberle's Facebook page he is listed as being from Saint Louis, Missouri. He now lives in San Antonio, Texas, but has been in South Africa since May.



He recently posted photographs of the chimps he was working with on the website, tagged with comments such as 'so cute' beside a picture of two of them sleeping.



Another portrays a wide-mouthed chimp named Cozy, who suffered brain damage after being abused prior to his rescue. Mr Oberle describes the primate as 'still the best', adding: 'Cozy may hit people in the head with rocks but it's not his fault'.



One of Cozy's victims, Stacey Johns, is also pictured in the album with blood pouring from a wound in her head.

Powerful beasts: Chimpanzees sit in an enclosure at the Chimp Eden rehabilitation center, near Nelspruit, South Africa

Brutal: The 26-year-old was dragged for more than a mile by the chimps at the Goodall Institute Chimp Eden (pictured)

Mr Oberle, apparently fascinated by the primates, was experimenting with different food types and on Monday wrote that they enjoyed an offering of oatmeal. Last Saturday he wrote that 'mustard was a big hit'.

The sanctuary opened six years ago and is home to rescued chimpanzees, many of which suffered horrific abuse, hunted for their meat or used in the entertainment industry or at roadside zoos.



One adult male arrived almost completely shaven and dressed as a little boy, wearing a gold watch and carrying a suitcase of clothes, the center's website said.



David Oosthuizen, executive director, said in a statement: 'This is a terrible tragedy that should never happen. All our thoughts and prayers are with this young man and his family.'

He added that the chimps’ power makes them a force to be feared. They have six times the strength of a human being.

'Any interaction between humans and wild animals can be dangerous as wild animals are often very strong and can act aggressively if approached or if they feel threatened,' Mr Oosthuizen said.

'Additionally, the chimpanzees at Chimp Eden have suffered horrible injuries and abuse from humans and therefore have to be treated with caution.'

The two chimpanzees were placed in their night enclosure after the attack and will be held there pending the investigation, after which they would be returned to their enclosure, said chairman Edwin Jay.

In a statement a spokesman from Mr Oberle's university said: 'We were saddened to learn that one of our students, Andrew Oberle, sustained serious injuries as the result of a chimpanzee attack. Our hearts go out to Andrew and his family.'

In May, Mr Oberle was awarded in Geographic Information Science from UTSA. Prior to enrolling at the school he studied at St Mary's University in San Antonio.