Surili

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.[2][3] 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),[2] 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.[2]

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.[3] A few species have been observed in monogamous pairings (particularly the Mentawai langur),[3] although this might be a reaction to the decrease of their habitat. Lone males and all-male groups have also been reported.[2] The groups are hierarchically developed, with intergroup communication that is both vocal and postural.

The surilis' diet consists of leaves, fruits, and seeds.[3]

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.[2]

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,[4] and the Sarawak surili has been referred to as "one of the rarest primates in the world."[5] 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,[6] though it remains one of the world's most endangered primates.[7]

Two other genera, Trachypithecus and Semnopithecus, were formerly considered subgenera of Presbytis.[1] The species-level taxonomy of Presbytis is complex, and significant changes have been proposed for several in recent years.[1][8][9][10]

Genus Presbytis – Eschscholtz, 1821 – nineteen species

Common name	Scientific name and subspecies	Range	Size and ecology	IUCN status and estimated population
Black Sumatran langur	P. sumatranus (S. Müller, Schlegel, 1841)	Island of Sumatra in Indonesia	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[12] Diet: Fruit, leaves, seeds and flowers[12]	EN  Unknown [12]
Black-and-white langur	P. bicolor Aimi, Bakar, 1992	Island of Sumatra	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[13] Diet: Fruit, seeds, and leaves[11]	DD  Unknown [13]
Black-crested Sumatran langur	P. melalophos (Raffles, 1821)	Island of Sumatra	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest and shrubland[14] Diet: Fruits and leaves, as well as seeds and flowers[15]	EN  Unknown [14]
East Sumatran banded langur	P. percura Lyon, 1908	Island of Sumatra	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[16] Diet: Fruit, seeds, and leaves[11]	CR  Unknown [16]
Hose's langur	P. hosei (Thomas, 1889)	Borneo	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[17] Diet: Leaves, unripe fruits, seeds, flowers, bird eggs and nestlings[17]	VU  Unknown [17]
Javan surili	P. comata (Desmarest, 1822) Two subspecies P. c. comata P. c. fredericae	Island of Java in Indonesia	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[18] Diet: Leaves, as well as fruits, flowers, and seeds[18]	VU  5,500 [18]
Maroon leaf monkey	P. rubicunda (Müller, 1838) Five subspecies P. r. carimatae P. r. chrysea P. r. ignita P. r. rubicunda P. r. rubida	Borneo	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest and inland wetlands[19] Diet: Leaves, seeds, and fruit, as well as flowers and pith[19]	VU  Unknown [19]
Siberut langur	P. siberu (Chasen, Kloss, 1928)	Island of Siberut in Indonesia	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[20] Diet: Fruit, seeds, and leaves[11]	EN  Unknown [20]
Mentawai langur	P. potenziani (Bonaparte, 1856)	Mentawai islands in Indonesia	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[21] Diet: Fruit, seeds, and leaves[11]	CR  Unknown [21]
Miller's langur	P. canicrus G. S. Miller, 1934	Eastern Borneo (in light green)	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[22] Diet: Fruit, seeds, and leaves[11]	EN  Unknown [22]
Mitered langur	P. mitrata Eschscholtz, 1821	Island of Sumatra	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[23] Diet: Fruit, seeds, and leaves[11]	VU  Unknown [23]
Natuna Island surili	P. natunae (Thomas, Hartert, 1894)	Island of Natuna Besar in Indonesia	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[24] Diet: Fruit, seeds, and leaves[11]	VU  9,000 [24]
Raffles' banded langur	P. femoralis (Martin, 1838)	Singapore and southern Peninsular Malaysia	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[25] Diet: Fruit, seeds, and leaves[11]	CR  200–250 [25]
Robinson's banded langur	P. robinsoni Thomas, 1910	Southern Malay Peninsula	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[26] Diet: Fruit, seeds, and leaves[11]	NT  Unknown [26]
Sabah grizzled langur	P. sabana (Thomas, 1893)	Eastern Borneo (in dark brown)	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[27] Diet: Fruit, seeds, and leaves[11]	EN  Unknown [27]
Sarawak surili	P. chrysomelas (Müller, 1838) Two subspecies P. c. chrysomelas P. c. cruciger	Northern Borneo	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[5] Diet: Fruit, seeds, and leaves[11]	CR  Unknown [5]
Thomas's langur	P. thomasi (Collett, 1893)	Northern island of Sumatra in Indonesia	Size: 42–62 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[28] Habitat: Forest[29] Diet: Fruit, leaves, and seeds, as well as flowers, bark, twigs, stalks, birds, bird eggs, algae, and insects[28]	VU  Unknown [29]
White-fronted surili	P. frontata (Müller, 1838)	Borneo	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[30] Diet: Fruit, seeds, and leaves[11]	VU  Unknown [30]
White-thighed surili	P. siamensis (Müller, Schlegel, 1838) Four subspecies P. s. cana P. s. paenulata P. s. rhionis P. s. siamensis	Southeastern Asia	Size: 42–61 cm (17–24 in) long, plus 50–85 cm (20–33 in) tail[11] Habitat: Forest[31] Diet: Fruit, seeds, and leaves[11]	NT  Unknown [31]

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