"They found out that though pandas' pregnancy takes about 120 to 170 days, it's only in the last month that the fertilized ovum is embedded," he says.

Another less known fact about pandas that Tan includes in the book is pandas are pigeon-toed in both of their two pairs of limbs, so "they walk in clumsy style with twisted hips".

Drawn to observe and write about the pandas from the early 1980s, Tan sees humanity behind the panda stories.

"I'm deeply impressed by the panda's international appeal, and how fragile the species is," he says. "Without large human input, pandas are still endangered."

"Through pandas, human see their own situation. By saving pandas, Chinese people form an increasingly high awareness of environment protection," he says.

According to Xinhua News Agency, about 1,600 giant pandas live in the wild, mostly in the mountains of Sichuan province, while more than 300 live in captivity.

Tan has also penned poems about pandas, delivering the pandas stories with a poet's sharpness and passion.

"Tan Kai is able to see through the social phenomenon to understand the profound truth. He understands human emotions and has great storytelling skills," comments Liu Shahe, Sichuan's iconic writer.

Tan is excited to tell the story of one British man called David Turner.

Turner formed a special preference for pandas in the 1940s when London was under Nazi blitz.

Then a panda named Ming was in the zoo. While other animals were frightened and scattered by the bombs, Ming remained composed and ate and slept as usual. Ming was later pictured as the embodiment of British people "with high morale" in the anti-fascism war.

Some 60 years later, suffering a brain tumor, Turner was only able to learn things about pandas from the newspaper his wife read to him.

In 2003, with his doctor's permission, he got a chance to travel to Chengdu to see real pandas.

"That day all the young pandas in the base were let out and played freely with Turner.

Surrounded by the fluffy black and white creatures, he kept on pinching his face to make sure it wasn't a dream," Tan says.

"Turner said that day was the happiest day in his life," Tan says.