Presbytis

Presbytis is a genus of Old World monkeys also known as langurs, leaf monkeys, or surilis. Members of the genus live in the Thai-Malay Peninsula, on Sumatra, Borneo, Java and smaller nearby islands.<ref name=MSW3>Template:MSW3 Groves</ref>

Description

Surilis are rather small, slimly built primates. Their fur at the top is brown, grey, black, or orange, and at the lower surface whitish or greyish, sometimes also orange, with some species having fur designs at the head or at the hips.<ref name = Walker>Novak, R. M. (1999). Walker's Mammals of the World. 6th edition. Johns Hopkins University Press, Baltimore. Template:ISBN</ref><ref name = Rowe>Rowe, N. (1996). The Pictorial Guide to the Living Primates. Pogonias Press, Rhode Island. Template:ISBN</ref> Their German name of Mützenlanguren ("capped langurs") comes from the hair on their head, which forms a tuft. They differ from the other langurs by characteristics in the shape of their head (particularly the poorly developed or absent brow ridges, and the prominent nasal bones),<ref name = Walker/> in the teeth, and by the size of their small thumbs. Surilis range in adult length from 40 to 60 cm (with a 50- to 85-cm-long tail) and a weight of 5 to 8 kg.<ref name = Walker/>

Behaviour

Diurnal forest dwellers, they spend nearly their entire lives in the trees. They live in groups of up to 21 animals (typically 10 or fewer animals in most species) consisting of a male, several females, and their young.<ref name = Rowe/> A few species have been observed in monogamous pairings (particularly the Mentawai langur),<ref name = Rowe/> although this might be a reaction to the decrease of their habitat. Lone males and all-male groups have also been reported.<ref name = Walker/> The groups are hierarchically developed, with intergroup communication that is both vocal and postural.

Diet

The surilis' diet consists of leaves, fruits, and seeds.<ref name = Rowe/>

Breeding

Gestation time is 5–6 months, and births are typically of single young. Newborn animals are white colored and have a black strip at the back, although some have a cross-shaped mark. By one year old, the young are weaned and at an age of 4–5 years, they are fully mature. The typical life expectancy in the wild remains poorly known for most species, but captive Sumatran surilis have lived more than 18 years.<ref name = Walker/>

Conservation

Several species in this genus are restricted to regions with extensive habitat destruction, and are also threatened by hunting. Consequently, 16 of the 19 species are rated as vulnerable or worse by IUCN,<ref name = IUCN>IUCN (2008). 2008 IUCN Red List of Threatened Species. Retrieved on 2008-12-15.</ref> and the Sarawak surili has been referred to as "one of the rarest primates in the world."<ref name="IUCNSarawaksurili"/> Recently, a subspecies of Hose's langur called Miller's grizzled langur, thought to be extinct, was rediscovered in the Wehea Forest on the eastern tip of Borneo island,<ref>The Guardian, guardian.co.uk, Friday 20 January 2012: 'Extinct' monkey rediscovered in Indonesia jungle.</ref> though it remains one of the world's most endangered primates.<ref>Template:Cite news</ref>

Taxonomy

Two other genera, Trachypithecus and Semnopithecus, were formerly considered subgenera of Presbytis.<ref name=MSW3/> The species-level taxonomy of Presbytis is complex, and significant changes have been proposed for several in recent years.<ref name=MSW3/><ref>Template:Cite journal</ref><ref name=ang>Template:Cite journal</ref><ref name=abdul>Template:Cite journal</ref>

Sources

• Template:Cite book

External links

• Primate Info Net Presbytis Factsheets