 The former (the nominate subspecies), often known as the golden-headed or Cat Ba langur, is among the rarest primates in the world, and possibly the rarest primate in Asia, with population size estimated at less than 70 individuals.Both subspecies are overall blackish, but the crown, cheeks and neck are yellowish in "T. p. poliocephalus", while they are white in "T. p. leucocephalus", as suggested by its scientific name.According to the Cat Ba Langur Conservation Project, the Cat Ba langur's skin is black and the pelage color is dark brown; head and shoulder are bright golden to yellowish-white.