This year, as I have turned 62 years old, I have dwelt deeply on a cause to which I have devoted my entire life: studying and protecting the Yunnan snub-nosed monkey. This creature, endemic to the coniferous forests of the mountainous, southwestern regions of Yunnan and Tibet, was once believed to be extinct; there are now only 3,000 or so left, making them a highly endangered animal.

I began my research into this particular species of monkey upon graduating from Sun Yat-sen University, in southern China’s Guangdong province, back in 1982. The Ministry of Forestry and Agriculture had, in the 1970s, included the monkey on a list of the country’s endangered and protected species, though the animal’s place on this list had little practical benefit.

Back then, one couldn’t find photographic evidence of the monkey anywhere on Earth. Even the staff of Yunnan’s Baima Snow Mountain Nature Conservation Area — the only area at the time to specifically prioritize the monkey’s conservation — weren’t sure what the monkey that they were supposed to protect looked like: They thought its fur was golden, not black.

There was one group, however, who knew the monkey very well indeed: poachers. In the ’70s, hunters targeted the monkey for its meat, pelt, and bones. In China, wild animals are mostly poached for eating, for their supposed medicinal properties, or for their fur. It was precisely because of their efforts to catch and kill monkeys that poachers became experts on the species’ habitat and behavior.

In my quest to seek out the monkey in the remote depths of southeastern China’s primeval forest, I made friends with hunters all over the province. Every time I arrived at a new place, I would track down the most proficient poachers in the area and hire them to guide me to the monkeys. With the assistance of my poacher friends, I roamed thousands of kilometers of seemingly boundless forest in the Yun Mountains in order to seek out every existing group of snub-nosed monkeys.

These diagrams represent the geographic distribution of the different populations. They look simple enough, but they are actually the fruit of more than a decade of painstaking work. There are only 16 populations of Yunnan snub-nosed monkey left, with the total number of individual animals hovering somewhere between 2,000 and 3,000.

We now know that the monkeys can be divided into three main gene pools. Of these groups, the monkeys inhabiting the Laojun Mountain near Lijiang, in the northwest part of Yunnan, are most endangered; only two populations remain, one of which has fewer than 50 members.

As each poacher helped me in my search for the Yunnan snub-nosed monkey, I, in turn, persuaded many of them to lay down their arms. In time, some of them even became conservationists themselves.

In order to do that, I had to create an emotional affiliation between them and the monkeys. I would ask them to observe the snub-nosed monkeys in detail, and as they watched, I would explain to them that these monkeys are the most humanlike creatures on earth. Even though it is well-known that the chimpanzee shares nearly 99 percent of its DNA with humans, I have often felt my own character is more similar to our more distant cousin, the snub-nosed monkey.

I explained to my poacher friends that primates are an essential part of the forest ecosystem: If primates make their home in a certain area, it usually means the region is made up of primeval, old-growth forest. Primates also thrive near natural reservoirs that provide a constant supply of water to surrounding areas. Contributing to the conservation of the Yunnan snub-nosed monkey thus requires us to protect up to 6,000 square kilometers of primeval forest. This is vital, because there are now little more than 100,000 square kilometers of such forest left in China. By protecting the Yunnan snub-nosed monkey, we can protect a significant proportion of that land.

Among the former huntsmen who guided me through the forest, two in particular have become very good friends of mine: Zhang Zhiming and Yu Jianhua. In 1989, when we were both in our 30s, Zhang and I climbed Mt. Laojun in Lijiang together. We ate, slept, and worked on this mountain together for over five months.

During that time, our main topic of conversation was the monkey. I explained to him that the “great black monkeys” spoken about by Laojun’s hunters were in fact the Yunnan snub-nosed monkeys that we were looking for; that these monkeys were one of the rarest and most beautiful creatures in the world; and that the few that remained could only be found in the northwestern part of Yunnan Province, as well as in a very small number of places in Tibet. These monkeys, I convinced him, deserved our protection.

Before we climbed the mountain, Zhang quite literally viewed the snub-nosed monkey as fair game. The monkeys, he said, have ample meat on their bones and beautiful fur; their bones alone could be exchanged for more than 50 kilograms of rice. However, by the time we got down from the mountain, he had become a firm advocate for conservation. Since then, he has taken every opportunity to convince local hunters to change their ways, informing them that the mountain’s animal populations, as well as the number of fish and crustaceans in nearby water sources, have shrunk to the point where locals can no longer rely on hunting and fishing for survival. They must, he insists, abandon hunting and convert to farming.

Meanwhile, since I persuaded Yu and his fellow hunters to stop killing Yunnan snub-nosed monkeys in 1997, they have indefatigably followed the movements of different monkey populations in the hopes of gradually gaining their trust. I recall one day in 2008, when an entire population of monkeys seemed to lose their fear of humans practically overnight, allowing the overjoyed researchers to work with them with unprecedented ease.

In the past, owing to long-term poaching, the monkey would run away as soon as it laid eyes on humans. However, as our research continues, we have succeeded in continually closing the gap between the monkeys and us. As you can imagine, this has greatly facilitated scientific research. In the ’90s, I’d often go a month on the mountain without seeing any monkeys. Now, however, we are able to observe them at such close range that we are, at times, even able to tell them apart and study their individual personalities.

The imposing male in this photograph is named Red Spot. He has six mates and four children. Another male, not pictured here, is known as Stumpy, and his mate is named Flat Face. Together, they have two sons: Si Geng, who is 3 years old, and his younger brother, April, named after the month in which he was born last year.

It is clear to see that these hunters-turned-guardians have made an enormous contribution to the protection of the Yunnan snub-nosed monkey in the last 30 years or so. It is thanks to their efforts that today’s scientists are now able to observe snub-nosed monkeys up close, and that the monkey has garnered an increasing amount of attention both in China and abroad. One could even say that the key to the successful protection of this species lies in the conversion of hunters into conservationists.

However, my conservationist friends and I have grown old: Zhang is now 66, and Yu is 64. While I receive a salary and pension for my academic work, they and many other former hunters have only ever been hired on a contractual basis, as they don’t have any academic qualifications. They don’t earn a regular salary and won’t receive any more money following their retirement. What will they do, then, in the years to come? This is a source of great concern to me.

Translator: Lewis Wright; editors: Wu Haiyun and Matthew Walsh.

(Header image: An adult male Yunnan sub-nosed monkey is pictured in the Baima Snow Mountain Nature Conservation Area, Yunnan province, Dec. 12, 2014. Xinglin Meng for Sixth Tone)