The establishment of EPRC has faced many difficulties, but began with two individuals of Delacour’s langur and Hatinh langur confiscated from the illegal wildlife trade. The Center currently houses about 150 individuals of 15 species and sub-species in which 6 species nowhere else in captivity. These include Delacour’s langur (Trachypithecus delacouri), Hatinh (Trachypithecus laotum hatinhensis), Black langur (Trachypithecus laotum ebenus), Lao langur (Trachypithecus laotum laotum), Cat Ba langur (Trachypithecus poliocephalus poliocephalus), and Grey-shanked Douc langur (Pygathrix cinerea).
Nine species have been successfully bred in captivity, Delacour’s langur, Hatinh langur, Black langur and Grey-shanked Douc langur the first time in captivity. The proportion of these species reproduction has been very high, with five Delacour’s langurs giving birth to five offspring and ten Hatinh langurs giving birth to 16 individuals at the Center. The Center is only foundation in the world that implements captive rescue for 3 species of Douc langur, including the Grey-shanked Douc langur, Red-shanked Douc langur and the Black-shanked Douc langur with a total of 28 individuals.
Besides its rescue duties, the Center has also led important activities including a program to release captive animals back into the wild. In 2007, eight Hatinh langurs have been released into the semi-wild enclosure at Phong Nha Ke Bang national park, Ba Be national park and have achieved initial successes in searching for food, habitat use and other behaviors.