Due to uncontrolled hunting and large-scale deforestation, the number of Hainan gibbons has decreased from more than 2000 in the 1950s to fewer than 10 in the 1970s. Found only on the Chinese island of Hainan, the gibbon is the world’s rarest primate. But continuous efforts from conservation groups are finally paying off with the ape’s population now exceeding 30 individuals.

“Even though the numbers are still small, you can see a future for this animal,” said senior conservation officer Philip Lo Yik-fui of Hong Kong-based Kadoorie Conservation China, which was driving efforts to protect the gibbons and expand their habitat.

The endangered species is restricted only to Hainan, the tropical island off the southern coast of China. Adult males are jet black, while the fur of females turns a rich gold when they reach maturity. Like other species of gibbons globally, the Hainan gibbon suffered from loss of habitat as forests were felled for agriculture. They were also hunted for use in traditional medicine and the pet trade.

In 2003, when the conservation project began, 13 gibbons were found living in two family groups, usually comprising a male, two females, and their offspring. At the time, they were found only in a 16sq km patch of forest high in the mountains of the sprawling Bawangling National Nature Reserve — an area far from ideal as juicy fruit such as figs and lychee preferred by the gibbons did not grow there.

Over the years, however, conservationists have not only monitored the population of gibbons to prevent poaching and learn about them but also planted more than 80,000 native fruit trees including wild lychee and different types of fig to help expand their habitat.

Additionally, the conservation team has also enlisted from the local community former hunters familiar with the forests to help monitor the gibbons, and also provide the hunters with a renewed sense of purpose.

Eventually, conservation efforts had paid off, as the Hainan gibbon is the only one of 19 recognized species of gibbons showing a stable increase in numbers. And while the gibbons are reproducing at a stable pace, the goal is to raise the population to more than 50, which would take them past the threshold of “critically endangered” to “endangered” on the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species.