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The Tonkin snub-nosed monkey or Dollman's snub-nosed monkey (''Rhinopithecus avunculus'') is a critically endangered, slender-bodied arboreal colobine, endemic to northern Vietnam. Recorded at elevations between 200 to 1,200 m, its distribution is currently restricted to small fragmented tropical evergreen forests associated with steep karst limestone hills and mountains. Five isolated extant populations have been identified since its rediscovery in 1992. Despite heralded as a flagship species and subsequently receiving international attention and conservation actions, the population trend remains on the decline; therefore causing it to be continuously listed as one of "The World's 25 Most Endangered Primates."〔(snub nosed monkeys )〕 since the first global non-human primate biennial assessment began in 2001. Habitat loss and hunting are some of the major causes for declines of naturally occurring populations of non-human primates, including the Tonkin Snub-nosed monkey. Decades of expanding human population and increasing demands for scarce agriculturally viable lands have led to the loss and fragmentation of the monkey's habitats. However, habitats of known Tonkin snub-nosed monkey populations were long lost and fragmented prior to their rediscovery. A pioneering study in 1993, in Na Hang Nature Reserve, obtained a population count of 72 individuals (estimated 80), and a subsequent study at the same site in 2005 obtained a population count of 17 individuals (estimated 22). Evidenced by both primary and secondary data, the population decline within that 13-year period can only be attributed to hunting activities.〔 Sightings of the monkey have become increasingly rare. The primate was thought to be extinct until the 1990s, when a small population was discovered in Na Hang District in Tuyên Quang Province of Vietnam. Heavy poaching for food as well as the wildlife black market and the destruction of habitat are the main reasons why the Tonkin snub-nosed monkey is considered one of the planet's most critically endangered primate species . By 2008, when a small population with three infants was discovered in a remote forest, fewer than 250 of the primates were thought to exist.〔("Glimmer of hope for rare monkey" ) (BBC News), 7 December 2008〕 In December 2013, Fauna & Flora international released the result of a population survey conducted between September and October of that year in the Khau Ca Species and Habitat Conservation Area, Ha Giang province, Vietnam. The survey identified between 108-113 individuals alive in the conservation zone, nearly half of the standing estimate for world population and the highest number at the site since populations began to be monitored.〔() (Phys.org), 10 December 2013〕 Researchers took this as an encouraging sign that conservation efforts were making an impact on the species' steeply declining numbers. ==Biology== The Tonkin snub-nosed monkey is diurnal and its diet consists of a range of leaves, fruits, flowers and seeds. Detailed information on this species can be found on (Arkive.org ) and (Alltheworldsprimates.org ) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tonkin snub-nosed monkey」の詳細全文を読む スポンサード リンク
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