Photo provided to China Daily

In 1998, Li saved a deer from the flood that turned the reserve into a river. It was a baby deer that had been deserted by its mother during its escape. He named it Jiaojiao, and the little deer followed Li wherever he went for almost a year. But finally Li released Jiaojiao back into the wild.

Now Jiaojiao has given birth eight times, and shows no trace of human interference. Li is delighted.

"Although I felt sad when it left me, I really wanted it to go back to its herd and be accepted by its fellows," Li says.

The milu's colloquial name is sibuxiang, which translates as "the four unlikes" because they have a horse's face, deer's antlers, a donkey's tail and a camel's neck. French missionary Pere Armand David took the animal to Paris in 1866. It was the first time the wider world learned about this species of deer.

The number of milu around the world has surpassed 4,000. But it remains on China's endangered and rare species list alongside the giant panda.

"The milu population is large enough considering there were only 18 of the animals 100 years ago. What we care about now is returning them to the wild, so they're not still tied to the reserve," Li says.

The reserve's core zone can house at most 600 milu. But there are already about 500. The limited capacity sets a critical cap on the expansion of milu's population, Li says.

"Our reserve is like an isolated island artificially separated from the outside. Our ultimate goal is to let milu go wild outside the reserve and to live harmoniously with humans," he says.