White-fronted Surili
Encyclopedia
The white-fronted surili (Presbytis frontata) is a species of primate
in the Cercopithecidae family. It is found in Indonesia
, Malaysia, and possibly Brunei
. Its body is mainly grey-brown, with a distinct white spot on the forehead. Its chin and lower cheeks are greyish. Its natural habitat
is subtropical or tropical dry forest
s. It is threatened by habitat loss.
to assist in the breakdown of cellulose and also has enlarged salivary gland
s. The incisor
s are narrow and the molar
s have a sharp, high crest. The jaw is deep and the face is short and broad. The thumb is reduced and the hindlimbs are longer than the forelimbs. The average body mass for the adult male is 5.67 kg and for adult females is 5.56 kg.
There are two subspecies, P. f. frontata and P. f. nudifrons. P. f. frontata is brownish in colour, with darker arms, legs, top and sides of the head and tail. The chin and lower cheeks are greyish. The white spot on the forehead is roughly triangular in shape. Meanwhile, P. f. nudifrons is dark greyish with blackish hands, feet and base of tail. The underparts and distal end of tail are paler grey-brown with white throat. The white spot on the forehead is rather square compare to P. f. frontata and is divided by a vertical line of short black hairs.
. It was recorded in the east between the Kayan River
and Banjarmasin
in the south. Meanwhile P. f. nudifrons was recorded from central Sarawak between the upper Rajang River
and upper Batang Lupar, including Lanjak Entimau Wildlife Sanctuary
.
because the population trends are decreasing to more than 30% over the last three generation (approximately 30 years). This is due to the hunting for the meat and traditional medicine, as well as habitat loss. The forest habitat is being loss rapidly, especially due to oil palm plantations and other anthropogenic habitats. For conservation, this species is protected Indonesian law and is totally protected in Sarawak. There are at least seven protected areas known, which only one in Malaysia, Lanjak-Entimau Wildlife Sanctuary.
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
in the Cercopithecidae family. It is found in Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, Malaysia, and possibly Brunei
Brunei
Brunei , officially the State of Brunei Darussalam or the Nation of Brunei, the Abode of Peace , is a sovereign state located on the north coast of the island of Borneo, in Southeast Asia...
. Its body is mainly grey-brown, with a distinct white spot on the forehead. Its chin and lower cheeks are greyish. Its natural habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
is subtropical or tropical dry forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...
s. It is threatened by habitat loss.
Physical Characteristic
The white-fronted surili has a tall sagittal crest that leans forward. This species' dorsal body is mainly greyish brown and ventral side is yellowish brown in coloration, with a distinct white spot on the forehead. The tail is yellowish grey, with blackish coloration of hands, feet, brow, crown crest and cheeks. There is light colored frontal patch on the crown crest. This species has a sacculated stomachStomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
to assist in the breakdown of cellulose and also has enlarged salivary gland
Salivary gland
The salivary glands in mammals are exocrine glands, glands with ducts, that produce saliva. They also secrete amylase, an enzyme that breaks down starch into maltose...
s. The incisor
Incisor
Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...
s are narrow and the molar
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
s have a sharp, high crest. The jaw is deep and the face is short and broad. The thumb is reduced and the hindlimbs are longer than the forelimbs. The average body mass for the adult male is 5.67 kg and for adult females is 5.56 kg.
There are two subspecies, P. f. frontata and P. f. nudifrons. P. f. frontata is brownish in colour, with darker arms, legs, top and sides of the head and tail. The chin and lower cheeks are greyish. The white spot on the forehead is roughly triangular in shape. Meanwhile, P. f. nudifrons is dark greyish with blackish hands, feet and base of tail. The underparts and distal end of tail are paler grey-brown with white throat. The white spot on the forehead is rather square compare to P. f. frontata and is divided by a vertical line of short black hairs.
Ecology and habitat
This species is diurnal and arboreal. It is also primarily a folivorous species, but also consumes fruits and seeds. This species prefers to eat immature leaves to more mature ones. The group sizes range from 10 to 15 individuals. P. frontata can be found in tall lowland and hill dipterocarp forests, not above 300 meters. This species has also been observed in riverine and hill forest.Distribution
P. frontata is endemic to Borneo, and restricted to the south-east of Borneo, below 3°N and east of Barito RiverBarito River
Barito is a 890 km long river, located in South Kalimantan, Indonesia. It originates in the Muller Mountain Range from where it flows southward into the Java Sea...
. It was recorded in the east between the Kayan River
Kayan River
Kayan River is a river of Borneo, Indonesia.Tributaries include the Bahau River.-References:...
and Banjarmasin
Banjarmasin
Banjarmasin is the capital of South Kalimantan, Indonesia. It is located on a delta island near the junction of the Barito and Martapura rivers. As a result, Banjarmasin is sometimes called the "River City"...
in the south. Meanwhile P. f. nudifrons was recorded from central Sarawak between the upper Rajang River
Rajang River
The Rajang River is a river in Sarawak, Malaysia. The river is located in northwest of Borneo and it originates in the Iran Mountains. The river flows approximately 563 km to the South China Sea, making it the longest river in Malaysia....
and upper Batang Lupar, including Lanjak Entimau Wildlife Sanctuary
Lanjak Entimau Wildlife Sanctuary
The Lanjak Entimau Wildlife Sanctuary is situated on the island of Borneo, in Malaysia. It covers 1,870km², and is significant for orangutan conservation. Together with Batang Ai National Park these protected areas contain an estimated 1,400 orangutans...
.
Social behaviour and communication
The white-fronted surili moves through the forest quadrupedally. This species also moves through the forest by leaping. In the population, solitary males have been observed in this species. For communication, the males use loud calls to demarcate the group’s territory. There is also tactile communication, which is social grooming. This is when one individuals groom another to reinforce the bonds between individuals. For reproduction, they only gives birth to a single offspring.Threats and Conservation
This species is listed as vulnerableVulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
because the population trends are decreasing to more than 30% over the last three generation (approximately 30 years). This is due to the hunting for the meat and traditional medicine, as well as habitat loss. The forest habitat is being loss rapidly, especially due to oil palm plantations and other anthropogenic habitats. For conservation, this species is protected Indonesian law and is totally protected in Sarawak. There are at least seven protected areas known, which only one in Malaysia, Lanjak-Entimau Wildlife Sanctuary.