Book cover of The Last Monkey Trainers. [Photo provided to China Daily]

A 57-year-old trainer by the name of Yang Lin'gui is the main character in Ma's book.

Yang entered the profession when he was 29, and has often smuggled his monkeys on trains because of the rules governing the carriage of live animals on public transport. But he also did it to save money.

Yang, like his fellow trainers, formed small groups to make money mostly through street performances.

Inns were a luxury they couldn't afford, so they lived in abandoned factories or uninhabited shelters, sometimes even sleeping under the open sky.

They had very little food to eat, usually just plain noodles and steamed buns for days.

While their popularity has fallen even in rural China, the monkey trainers also face sharp criticism from animal protection organizations.

Even though there are no reliable statistics on monkey trainers, it is widely believed that there are only a few more than 1,000 in total, and the young generation isn't taking to the ancient profession as it is seen to be at odds with public empathy for animals in the modern world, the book says.

"It is getting more and more difficult to make a living out of training and performing with monkeys," Yang says.

Yang followed in his father's footsteps to become a monkey trainer, but his son, unwilling to accept the family legacy, is now opting out to work in a factory in Guangdong province, the book says.

Yang Jinlin, famous culture critic and former Phoenix TV commentator, praised Ma for presenting a complex subject in an objective way.