JOHANNESBURG (July 2, 2012)—The condition of University of Texas San Antonio graduate student Andrew F. Oberle, 26, who was critically injured when chimpanzees at a sanctuary in South Africa attacked him, was improving Monday, doctors said.

In a statement, Mediclinic Nelspruit said Oberle, who had been in critical condition since Thursday's attack, was stable enough Sunday for surgery to clean and stitch his multiple bites and attend to fractures and other injuries.

Oberle remains in intensive care, but is no longer in critical condition.

Two chimpanzees at the Jane Goodall Institute Chimpanzee Eden in eastern South Africa pulled Oberle under a fence into their enclosure.

Oberle, who’s studying anthropology, was leading a tour Thursday at the institute when he left the group and crossed once of two fences that separated him from the chimps.

When he neared the second fence, which was electrified, the two chimps reached beneath it, grabbed him and pulled him by his feet into the enclosure, where they mauled him.

A sanctuary worker fired a rifle into the air to frighten the chimps and Oberle was rescued.

Family members are at Oberle’s bedside, officials said.