You may think you know everything about pandas, but did you know mother pandas can suffer from postpartum depression?

Little-known details about giant pandas will be revealed in the book "Hello, I'm Panda," which made its debut at the Beijing International Book Fair on Wednesday.

Tan Kai, 70, the book's author, said he spent 33 years writing the book, which features a panda's first-person narrative and offers insight into the panda's emotional world.

"I've been writing about pandas for over 30 years, but it was not until 2011 that I decided to write a book on the panda's emotional life, when I saw a panda mom who had just given birth. She seemed exhausted, and her eyes were full of love and melancholy. I was so touched," Tan told Xinhua.

Tan has been a panda fan since he went to the Wolong Panda Reserve, the largest panda reserve in the world, located in South China's Sichuan Province, for the first time in 1980.

Since then, he has been to all the panda reserves in China. He also took part in the newly launched website "ipanda.com," which enables Internet users worldwide to watch live broadcasts of pandas living in a Chengdu-based breeding center.

As most publications about pandas are either picture books or popular-science books, Tan hopes that his work can convey the emotions that he felt from pandas to readers, especially the younger generation, in order to get them to care about the species and the planet.

Though first published in English, Tan Kai plans to have the book translated into more languages.

"We have been discussing copyright issues with publishers from Japan and Taiwan, and we will also participate in the Frankfurt Book Fair in October to introduce my book to the European and American markets," he said.

Pandas are native to China and one of the most endangered animal species in the world. About 1,600 pandas live in the wild, mostly in the mountains of China's western Sichuan Province, while more than 300 live in captivity.