Forest management officials from the northern province of Ninh Binh and German zoologists in Vietnam have repopulated three douc langurs born by rescued langurs to a local nature reserve.
The officials planned to return ten of the Delacour's langurs by the end of 2013 to Van Long flooded nature reserve, news website VnExpress reported Tuesday.
Van Long reserve is now home to many Delacour's langurs, an endangered species in Vietnam.
Tilo Nadlo, chief representative of Frankfurt Zoological Society which is a project partner, said the three langurs belong to second and third generations of a Vietnamese langur and a Chilean langur, which were rescued from hunters.
They have been raised in custody at the primate rescue center at Cuc Phuong National Park in the province.
Each of the released langurs is five years old and around five to six kilograms. They have received health checks and each received a chip in them to observe their development for at least one year.
The project aims at raising the species population in nature and enrich the gene sources for Vietnam and the world.
Vietnam only has around 200 Delacour's langurs left, which are scattered around limestone mountainous areas of the Red River delta.
The species is listed in the World's 25 Most Endangered Primates, selected and published by the International Union for Conservation of Nature Species Survival Commission Primate Specialist Group (IUCN/SSC PSG), the International Primatological Society (IPS), and Conservation International (CI).