Scientists estimate that between 281 and 317 individuals still exist in 19 distinct populations. Rampant development separates the remaining populations of this langur species, preventing the groups from interacting with one another. Fourteen of the groups are likely to disappear within the next decade, since they either lack a breeding pair or have unsustainably tiny populations. When hunters kill a male critical for reproduction, for example, it spells annihilation for the entire group.
Delacour's langur is threatened mostly from hunting. Poachers kill the animal not only for meat, but for bones, organs and tissues that are used in the preparation of traditional medicines. Habitat destruction, development and the increase of agricultural lands also threaten the species.
Surprisingly, the monkeys are more likely to be killed within protected areas, since they are more densely forested and poachers are more difficult to spot. Since unprotected areas in northern Vietnam tend to have less wildlife, poachers often avoid them and regard them as less profitable, allowing the few remaining langur populations to survive. Conservation groups are working to increase the level of protection of the protected areas to ensure the survival of the species.
The Delacour's langur is so rare, that is was first described by science only in 1932. Until the late 1980s, there was virtually no information about the existence and distribution of the species. In the early 1990s, hundreds of the langurs were found on limestone moun