White-headed langur  (Trachypithecus poliocephalus)

Granted the dubious honour of being one of the International Primatological Society's ‘World's Top 25 Most Endangered Primates', the white-headed langur is in the company of such conservation priorities as the Sumatran orangutan (Pongo abelii) and the eastern gorilla (Gorilla beringei) (6). The focus of conservation efforts must fall primarily on the Cat Ba Island subspecies, with possibly as few as 59 individuals remaining today. This shockingly low number is the result of a massive 98% decline over the course of 40 years, from between 2,500 and 2,800 individuals in the 1960s to just 53 in 2000. Such a dangerously small population of Cat Ba langurs gives the impression that the Chinese subspecies, Trachypithecus poliocephalus leucocephalus, is thriving, with between 600 and 800 individuals alive today. This is, of course, far from the truth, particularly as declines were recorded in the populations at Longgang National Nature Reserve and the Fusui Rare and Precious Animal Reserve in 1998 (5).

In both range states of this monkey species, the major threat is hunting, which is exacerbated by habitat destruction and exploitation; for the creation of sugarcane plantations in China (5), and for timber, fuel-wood, honey, bamboo shoots, edible roots, and frogs and geckos in Vietnam (7). Cat Ba Island has seen considerable change in the past 20 – 30 years. Prior to 1979 very few people lived on the island, but it is now home to a large population, of whom 12,300 live in the buffer zone of Cat Ba National Park, and 850 in the park itself. Until 1989 commercial logging took place but this is no longer viable due to the scarcity of large trees (7).

Hunting of this rare primate is not for food, as the meat is said to be smelly and fetid, but for the creation of ‘monkey balm', a traditional ‘medicinal' preparation. Currently the Cat Ba langurs are split into just a few isolated sub-populations, many of which are all-female groups. This fragmentation creates further challenges for the recovery of the population due to low reproductive rates and the dangers of inbreeding (3).

With just 53 Cat Ba langurs in the wild and two in captivity at the Endangered Primate Rescue Centre of Cuc Phuong National Park, the Cat Ba Langur Conservation Project was started in 2000 by Munster Zoo and the Zoological Society for the Conservation of Species and Populations (ZGAP). Given the cause of the langur's decline, the main aim of the project was to halt poaching, with the additional intention of promoting conservation awareness amongst the inhabitants of Cat Ba Island. The project has been extremely successful in dramatically reducing deaths as a result of poaching, bringing the number from 30 deaths in the eight months prior to its start, to three deaths in the first four years of the project. In this time nine langurs were born and have survived. The langurs are closely monitored and protection measures are in place, particularly in the newly created langur sanctuary within the National Park. This highly protected area is home to 20 individuals from a large, reproducing group, which are protected by a rotation of 20 rangers – an incredible ratio of one ranger to one langur. The sanctuary is visibly marked around its circumference and is inaccessible to tourists. The Cat Ba Langur Conservation Project has constructed two new ranger stations, provided boats to ease patrols and has even seen the voluntary relocation of several local, floating households to support the rangers (3). The Cat Ba langur also has the support of Flora and Fauna International's Flagship Species Fund (5) and the Cat Hai District Women's Union, who implemented a project entitled ‘Contributing to Biodiversity Conservation in Cat Ba National Park through Community Activity' (7).

Following the finding of a decline in the white-headed black langur in China, efforts were made to conserve this subspecies. With funding from the Asian Development Bank, a survey in January 2003 showed evidence of some recovery in the Fusui populations (5), and numbers in Chongzuo have seen a rise from less than 100 to more than 200 individuals since Professor Pan Wenshi of Peking University began a research program in 1996 that concentrated on the subspecies (5). Tourism has become central to economy of both Vietnam and China, and now must be controlled to prevent the disturbance of recovering habitats and species in the Conservation International's Indo-Burmese Biodiversity Hotspot (7).