Eating bamboo slowly, Long Long looks no different from other pandas in the Chengdu Research Base of Giant Panda Breeding in Sichuan province.

But the 20-year-old male panda, the equivalent of 60 in human terms, has been rescued from the wild.

"If workers had spotted it one or two days later, he would have been dead," said Zhao Zhilong, chief of the administrative bureau of the Longxi Hongkou Nature Reserve in Dujiangyan, Sichuan province.

While patrolling the mountainous reserve on April 17, workers found the critically ill and starving panda.

"It lay on the ground and only took a few steps occasionally. Normally, a panda would flee at the sight of people," Zhao said.

More than two hours later, a rescue team of vets and keepers from the research base rushed to the scene.

"We found it suffering from severe malnutrition. An adult male panda weighs more than 110 kilograms. But it was 62 kg," said Lan Jingchao, chief of the panda hospital at the base.

The panda was missing a claw.

"We had to apply venous transfusion through its neck because its blood vessels had caved in. In the process, it stopped breathing for some time and we had to inject a respiratory stimulant to restore its breath," he said.

At night, the panda arrived in the quarantine room in the base's hospital. Responding to the new environment, it walked around and sat in a corner motionlessly, fell into a coma and stopped breathing.

After receiving a transfusion of medicine for more than three hours, it woke up in the wee hours the next day.

Medical checks showed it suffered from severe heart disease and liver damage and had many worms inside.

"In the ensuing six days and nights, it did not take a drop of water or any food. The rescue team worked around the clock to give it a transfusion of water, electrolytes, vitamins, nutrient solution and medicine," Lan said.

On the morning of April 24 when Lan offered it a bamboo shoot, the panda held it and slowly swallowed it all.

"We were so excited, for it could survive only if it could eat. I patted its back and said: 'You are hopeful,'" Lan said.

After continued treatment, the panda is now 69 kg and in stable condition. It is temporarily out of danger for its life, he said.

Pandas can be ferocious when people approach them. In 2010, a panda in the Bifengxia base of the Wolong Nature Reserve in Ya'an, Sichuan, bit off part of a keeper's finger.

But Long Long was docile to its rescuers.

"When I touch it as a token of friendship, it does not threaten me. It has a grateful heart to people who have saved it."

Three vets and three keepers take turns working day and night to monitor the panda.

Sick wild pandas are returned to the wild once they recover. But it is unknown if Long Long could be strong enough to be returned to the wild. If it could not, it would call the base home.