Andrew Oberle, who had been in critical condition since Thursday's attack, was stable enough on Sunday for doctors to bring him into the operating room to clean and stitch his multiple bites and attend to fractures and other injuries sustained during the attack by two chimpanzees.
During the tour on Thursday, Oberle left the group and crossed one of two fences separating him from the animals into a "no-go zone."
When Oberle neared the second fence, which was electrified, two alpha male chimpanzees named Nikki and Amadeus reached underneath and pulled him by his feet into their enclosure.
According to emergency officials, he was dragged nearly a half a mile and lost and ear and several fingers during the attack.
Oberle remains in intensive care, but is no longer in a critical condition.
The sanctuary was opened by famed primatologist Jane Goodall in 2006 as a refugee for mistreated and rescued animals.
The chimps involved in the attack were part of a group rescued from Angola and were brought to South Africa more than a decade ago.