Gao Gao the panda is on the mend after undergoing surgery at the San Diego Zoo to remove his right testicle because of a tumor.

The panda, which has five cubs and is estimated to be about 24 years old, underwent the successful, hour-long surgery Tuesday. He's now in a private habitat away from the public, where he'll remain throughout his recovery.

"He's doing well," zoo spokeswoman Jenny Mehlow told ABC News. "He was sleeping most of the morning and started eating again. Now we're just making sure to get back on his usual schedule."

Gao Gao's usual schedule consists mainly of lounging and eating bamboo, Mehlow said.

Gao Gao the panda underwent surgery this week because of a testicular tumor. (Credit: Courtesy San Diego Zoo)