79-589: Deli River (Indonesian: Sungai Deli) is a river located in Sumatra , Indonesia, and courses through Medan before discharging to the Strait of Malacca near the port city of Belawan . It is one of the eight rivers in Medan. The Deli Sultanate was founded on the delta of the river around 1640, and later around the 19th century, this river acted as an artery of trade for the sultanate to other areas. The forest area in
158-565: A wetland of international importance under the Ramsar Convention . Sumatra has lost almost 50% of its tropical rainforest since 1980. Many species are now critically endangered , such as the Sumatran ground cuckoo , the Sumatran tiger , the Sumatran elephant , the Sumatran rhinoceros , and the Sumatran orangutan . Deforestation on the island has also resulted in serious seasonal smoke haze over neighbouring countries, such as
237-491: A 9.2 earthquake shook Bengkulu and Western Sumatra. Both events caused large tsunamis . Earthquakes are very common throughout the coastal area of the west and center of the island, and tsunamis are common due to the high seismicity in the area. By population, Medan is the largest city in Sumatra. Medan is also the most visited and developed city in Sumatra. Sumatra supports a wide range of vegetation types that are home to
316-477: A delay of many years in the development of secondary sexual characteristics, such as cheek flanges and muscle mass. Males exhibit bimaturism, whereby fully flanged adult males and the smaller unflanged males are both capable of reproducing, but employ differing mating strategies to do so. The average interbirth rates for the Sumatran orangutan is 9.3 years, the longest reported among the great apes , including
395-568: A five-inch stick, strip off its bark, and then carefully collect the hairs with it. Once the fruit is safe, the ape will eat the seeds using the stick or its fingers. Although similar swamps can be found in Borneo, wild Bornean orangutans have not been seen using these types of tools. NHNZ filmed the Sumatran orangutan for its show Wild Asia: In the Realm of the Red Ape ; it showed one of them using
474-443: A lack of audible danger signals, but rather base their communication on gestures alone. In 2024, a wild Sumatran orangutan, called Rakus, was observed applying a paste made from chewed Fibraurea tinctoria leaves to a facial wound, a treatment which appeared to heal the wound weeks later. The Sumatran orangutan has five stages of life that are characterized by different physical and behavioral features. The first of these stages
553-454: A large seed and surrounded by a fleshy substance, such as durians , lychees , jackfruit , breadfruit , and fig fruits. Insects are also a huge part of the orangutan's diet; the most consumed types are ants, predominantly of the genus Camponotus (at least four species indet.). Their main diet can be broken up into five categories: fruits, insects, leaf material, bark and other miscellaneous food items. Studies have shown that orangutans in
632-471: A method of deforestation to re-use land for palm oil . This land is taken from the forest in which Sumatran orangutans live. An assessment of forest loss in the 1990s concluded that forests supporting at least 1,000 orangutans were lost each year within the Leuser Ecosystem alone. As of 2017, approximately 82.5% of the Sumatran orangutan population was strictly confined to the northernmost tip of
711-1119: A population of 14,613 Sumatran orangutans in the wild, doubling previous population estimates. A survey in 2004 estimated that around 7,300 Sumatran orangutans still live in the wild. The same study estimates a 20,552-square-kilometre (7,935 sq mi) occupied area for the Sumatran orangutans, of which only an approximate area range of 8,992 km (3,472 sq mi) harbors permanent populations. Some of them are being protected in five areas in Gunung Leuser National Park; others live in unprotected areas: northwest and northeast Aceh block, West Batang Toru river, East Sarulla and Sidiangkat. A successful breeding program has been established in Bukit Tiga Puluh National Park in Jambi and Riau provinces. Two strategies that are recently being considered to conserve this species are 1) rehabilitation and reintroduction of ex-captive or displaced individuals and 2)
790-417: A preferred male mate. However, adult males generally avoid contact with other adult males. Subadult males will try to mate with any female, although mostly unsuccessfully, since mature females are easily capable of fending them off. Mature females prefer to mate with mature males. Usually, there is a specific male in a group that mature females will exhibit preference for. Male Sumatran orangutans sometimes have
869-528: A rich variety of species, including 17 endemic genera of plants. Unique species include the Sumatran pine which dominates the Sumatran tropical pine forests of the higher mountainsides in the north of the island and rainforest plants such as Rafflesia arnoldii (the world's largest individual flower), and the titan arum (the world's largest unbranched inflorescence ). The island is home to 201 mammal species and 580 bird species. There are nine endemic mammal species on mainland Sumatra and 14 more endemic to
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#1732771920541948-436: A simple tool, a twig, to pry food from difficult places. There is also a sequence of an animal using a large leaf as an umbrella in a tropical rainstorm. As well as being used as tools, tree branches are a means of transportation for the Sumatran orangutan. The orangutans are the heaviest mammals to travel by tree, which makes them particularly susceptible to the changes in arboreal compliance. To deal with this, their locomotion
1027-675: A stiff economic decline as the heritage of the Srivijaya empire was superseded by the economic policy of the Singhasari and Majapahit . The Palembang sultanate experienced a terminal decline in the early 19th century. With the coming of the Dutch Empire , the many Sumatran princely states gradually fell under their control. Aceh posed major obstacles, as the Dutch were involved in the long and costly Aceh War (1873–1903). During
1106-526: A stronger relationship with peers while playing in groups. They are still young and act with caution around unfamiliar adults, especially males. At 8 years of age, female orangutans are considered fully developed and begin to have offspring of their own. Males, however, enter a stage called sub-adulthood. This stage lasts from 8 to around 13 or 15 years of age, and the orangutans weigh around 30 to 50 kilograms. Their faces are completely dark, and they begin to develop cheek flanges. Their beard starts to emerge, while
1185-529: A success, the orangutans having been fully rehabilitated, and the jungle (or the remaining part of) is now at saturation point, so the sanctuary no longer accepts new orphaned orangutans. The species has been assessed as critically endangered on the IUCN Red List since 2000. From 2000–2008 it was considered one of " The World's 25 Most Endangered Primates ." A survey published in March 2016 estimates
1264-476: A tree branch that is about a foot long, snap off the twigs and fray one end with its teeth. The orangutan will use the stick to dig in tree holes for termites . They will also use the stick to poke a bee's nest wall, move it around and catch the honey. In addition, orangutans use tools to eat fruit. When the fruit of the Neesia tree ripens, its hard, ridged husk softens until it falls open. Inside are seeds that
1343-578: Is 2862 mm. The wettest month is October, with an average of 446 mm rainfall, and the driest is June, with 129 mm rainfall. Sumatra Sumatra ( / s ʊ ˈ m ɑː t r ə / ) is one of the Sunda Islands of western Indonesia . It is the largest island that is fully within Indonesian territory, as well as the sixth-largest island in the world at 482,286.55 km (182,812 mi. ), including adjacent islands such as
1422-495: Is also an area in the archipelago that received the spread of Islam first compared to other islands or other areas. The island of Sumatra became the first area to receive the spread of Islam because of the position of the island of Sumatra which is close to the Malacca strait. The initial process of Islamization related to trade and also the formation of the kingdom. Islam entered Sumatra through pious Arabs and Tamil traders in
1501-441: Is also more arboreal than its Bornean cousin; this could be because of the presence of large predators, like the Sumatran tiger . It moves through the trees by quadrumanous locomotion and semibrachiation . As of 2017, the Sumatran orangutan species only has approximately 13,846 remaining members in its population. The World Wide Fund for Nature is thus carrying out attempts to protect the species by allowing them to reproduce in
1580-521: Is also used as an inter-ethnic means of communication in some parts of Aceh province. Religion in Sumatra (2023) The majority of people in Sumatra are Muslims (87.12%), while 10.69% are Christians, and less than 2.19% are Buddhists and Hindus. Sumatra is one of seven geographical regions of Indonesia , which includes its adjacent smaller islands. Sumatra was one of the eight original provinces of Indonesia between 1945 and 1948. Including adjacent archipelagoes normally included with Sumatra (such as
1659-399: Is becoming increasingly common in captive orangutans, due to the fact that they are exposed to the human strain of Streptococcus in captivity. At first, both strains are treated and cured with antibiotics along with rest. Yet, in 2014, a Sumatran orangutan, ten years in captivity, was the first of its species to die from Streptococcus anginosus . This remains the only known case, but raises
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#17327719205411738-444: Is characterized by slow movement, long contact times, and an impressively large array of locomotors postures. Orangutans have even been shown to utilize the compliance in vertical supports to lower the cost of locomotion by swaying trees back and forth and they possess unique strategies of locomotion, moving slowly and using multiple supports to limit oscillations in compliant branches, particularly at their tips. The Sumatran orangutan
1817-408: Is infancy, which lasts from birth to around 2.5 years of age. The orangutan weighs between 2 and 6 kilograms. An infant is identified by light pigmented zones around the eyes and muzzle in contrast to darker pigmentation on the rest of the face as well as long hairs that protrude outward around the face. During this time, the infant is always carried by the mother during travel, it is highly dependent on
1896-763: Is not a huge problem for the Sumatrans, occasional local hunting does decrease the population size. They have been hunted in the Northern Sumatra in the past as targets for food; although deliberate attempts to hunt the Sumatrans are rare nowadays, locals such as the Batak people are known to eat almost all vertebrates in their area. Additionally, the Sumatrans are treated as pests by Sumatran farmers, becoming targets of elimination if they are seen damaging or stealing crops. For commercial aspects, hunts for both dead or live specimens have also been recorded as an effect of
1975-474: Is one of the three species of orangutans . Critically endangered , and found only in the north of the Indonesian island of Sumatra , it is rarer than the Bornean orangutan but more common than the recently identified Tapanuli orangutan , also found in Sumatra. Its common name is based on two separate local words, orang 'people; person' and hutan 'forest', derived from Malay , and translates as 'person of
2054-613: Is reproducing. However it has been concluded that forest conservation costs twelve times less than reintroducing orangutans into the wild, and conserves more biological diversity. Orangutans have large home ranges and low population densities, which complicates conservation efforts. Population densities depend to a large degree on the abundance of fruits with soft pulp. Sumatran orangutan will commute seasonally between lowland, intermediate, and highland regions, following fruit availability. Undisturbed forests with broader altitudinal range can thus sustain larger orangutan populations; conversely,
2133-583: Is the largest producer of Indonesian coffee . Small-holders grow Arabica coffee ( Coffea arabica ) in the highlands, while Robusta ( Coffea canephora ) is found in the lowlands. Arabica coffee from the regions of Gayo, Lintong and Sidikilang is typically processed using the Giling Basah (wet hulling) technique, which gives it a heavy body and low acidity. Sumatra is a highly seismic island. Huge earthquakes have been recorded throughout history. In 1797, an 8.9 earthquake shook Western Sumatra, and in 1833,
2212-529: The 2005 Nias–Simeulue earthquake and the 2010 Mentawai earthquake and tsunami . Lake Toba is the site of a supervolcanic eruption that occurred around 74,000 years ago, representing a climate-changing event. The most important rivers in Sumatra belong to the catchment area of the South China Sea . Heading north to south, the Asahan , Rokan , Siak , Kampar , Indragiri , Batanghari flow into
2291-404: The 2013 Southeast Asian haze which caused considerable tensions between Indonesia and affected countries Malaysia and Singapore . The widespread deforestation and other environmental destruction in Sumatra and other parts of Indonesia has often been described by academics as an ecocide . Several unconnected railway networks built during Netherlands East Indies exist in Sumatra, such as
2370-819: The Barisan Mountains in the west and swampy plains in the east. Sumatra is the closest Indonesian island to mainland Asia. To the southeast is Java , separated by the Sunda Strait . To the north is the Malay Peninsula (located on the Asian mainland), separated by the Strait of Malacca . To the east is Borneo , across the Karimata Strait . West of the island is the Indian Ocean . The Great Sumatran fault (a strike-slip fault), and
2449-532: The Malacca Strait , while the island's largest river, the Musi , flows into the sea at Bangka Strait in the south. To the east, big rivers carry silt from the mountains, forming the vast lowland interspersed by swamps. Even if mostly unsuitable for farming, the area is currently of great economic importance for Indonesia. It produces oil from both above and below the soil – palm oil and petroleum . Sumatra
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2528-588: The North Sumatra province along the border with NAD, particularly in the Lake Toba forests. A survey in the Lake Toba region found only two inhabited areas, Bukit Lawang (defined as the animal sanctuary ) and Gunung Leuser National Park . Bukit Lawang is a jungle village, 90 kilometres (56 mi) northwest of Medan, situated at the eastern side of Gunung Leuser National Park. An orangutan sanctuary
2607-584: The Second World War , Japan invaded Sumatra in 1942. The Free Aceh Movement fought against Indonesian government forces in the Aceh Insurgency from 1976 to 2005. Security crackdowns in 2001 and 2002 resulted in several thousand civilian deaths. The island was heavily impacted by both the 1883 Krakatoa eruption and the 2004 Boxing Day Tsunami . Sumatra’s population as of 2023 was estimated to be about 60,795,669 ; it has about
2686-478: The Simeulue , Nias , Mentawai , Enggano , Riau Islands , Bangka Belitung and Krakatoa archipelago . Sumatra is an elongated landmass spanning a diagonal northwest–southeast axis. The Indian Ocean borders the northwest, west, and southwest coasts of Sumatra, with the island chain of Simeulue , Nias , Mentawai , and Enggano off the western coast. In the northeast, the narrow Strait of Malacca separates
2765-577: The Sunda megathrust (a subduction zone ), run the entire length of the island along its west coast. On 26 December 2004, the western coast and islands of Sumatra, particularly Aceh province, were struck by a tsunami following the Indian Ocean earthquake . This was the longest earthquake recorded, lasting between 500 and 600 seconds (8.33–10 minutes). More than 170,000 Indonesians were killed, primarily in Aceh. Other recent earthquakes to strike Sumatra include
2844-614: The World Wide Fund for Nature , who joined forces with several other organizations to stop the clearing of the biggest part of remaining natural forest close to the Bukit Tigapuluh National Park. In addition to the above extant wild populations, a new population is being established in the Bukit Tigapuluh National Park (Jambi and Riau Provinces) via the re-introduction of confiscated illegal pets. This population currently numbers around 70 individuals and
2923-479: The 13th century. In terms of economic development the port of Banda Aceh only started to face competition in the 18th century when more ports were constructed in Sumatra for maritime transport . Nevertheless, major pepper suppliers used the port of Banda Aceh at the beginning of the 19th century. The port in Medan grew swiftly in the late 19th and early 20th century. Meanwhile the medium sized port of Palembang faced
3002-1250: The 2010 census (including Riau Islands , Bangka Belitung , Nias , Mentawai , Simeulue and islands around it) There are over 52 languages spoken, all of which (except Chinese and Tamil) belong to the Malayo-Polynesian branch of the Austronesian language family. Within Malayo-Polynesian, they are divided into several sub-branches: Chamic (which are represented by Acehnese in which its closest relatives are languages spoken by Ethnic Chams in Cambodia and Vietnam), Malayic ( Malay , Minangkabau and other closely related languages), Northwest Sumatra–Barrier Islands ( Batak languages , Gayo and others), Lampungic (includes Proper Lampung and Komering ) and Bornean (represented by Rejang in which its closest linguistic relatives are Bukar Sadong and Land Dayak spoken in West Kalimantan and Sarawak ( Malaysia )). Northwest Sumatra–Barrier Islands and Lampungic branches are endemic to
3081-477: The 6th and 7th centuries AD. At the beginning and end of the 13th century the formation of the kingdom, the king of the Samudra kingdom had converted to Islam. Marco Polo visited the island in 1292, and his fellow Italian Odoric of Pordenone in 1321. Aceh in the north of Sumatra became known in the 16th century as trading centre for the pepper trade by shipping quality piperaceae ( pepper ). Aceh became
3160-529: The Bornean orangutan, the Sumatran orangutan tends to be more frugivorous and especially insectivorous . Preferred fruits include figs and jackfruits . It will also eat bird eggs and small vertebrates . Sumatran orangutans spend far less time feeding on the inner bark of trees. Wild Sumatran orangutans in the Suaq Balimbing swamp have been observed using tools . An orangutan will break off
3239-442: The Bornean orangutan. Infant orangutans will stay close to their mothers for up to three years. Even after that, the young will still associate with their mothers. Both the Sumatran and Bornean orangutans are likely to live several decades; estimated longevity is more than 50 years. The average age of the first reproduction of male P. abelii is around 15.4 years old. There is no indication of menopause . Nonja , thought to be
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3318-565: The Indonesian government announced a plan to protect Sumatra's remaining forests. The island includes more than 10 national parks, including three which are listed as the Tropical Rainforest Heritage of Sumatra World Heritage Site – Gunung Leuser National Park , Kerinci Seblat National Park and Bukit Barisan Selatan National Park . The Berbak National Park is one of three national parks in Indonesia listed as
3397-456: The Ketambe area in Indonesia ate over 92 different kinds of fruit, 13 different kinds of leaves, 22 sorts of other vegetable material such as top-sprouts, and pseudo-bulbs of orchids. Insects included in the diet are numbered at least 17 different types. Occasionally soil from termite mounds were ingested in small quantities. When there is low ripe fruit availability, Sumatran orangutans will eat
3476-686: The Portuguese throughout the 16th and 17th century. When the Dutch were weakened in the 18th century the British empire began to actively intervene in Aceh, establishing close relations between Banda Aceh and Penang . In the 17th and 18th century the Aceh Sultanate battled the Siak sultanate in the south of Sumatra. The port city of Banda Aceh was recorded in European historical writings since
3555-563: The Riau Islands, Nias and the Bangka-Belitung group), it now covers ten of Indonesia's 38 provinces , which are set out below with their areas and populations. The longest axis of the island runs approximately 1,790 km (1,110 mi) northwest–southeast, crossing the equator near the centre. At its widest point, the island spans 435 km (270 mi). The interior of the island is dominated by two geographical regions:
3634-519: The backbone of the island, while the northeastern area contains large plains and lowlands with swamps, mangrove forest and complex river systems. The equator crosses the island at its centre in West Sumatra and Riau provinces. The climate of the island is tropical , hot, and humid. Lush tropical rain forest once dominated the landscape. Sumatra has a wide range of plant and animal species but has lost almost 50% of its tropical rainforest in
3713-495: The demand by European and North American zoos and institutions throughout the 20th century. Sumatran orangutans have developed a highly functioning cardiovascular system. However, with this development of hugely improved air sacs in their lungs, air sacculitis has become more prevalent among orangutans in this species. Air sacculitis is similar to streptococcal infection , e.g. strep throat in Homo sapiens . The bacterial infection
3792-509: The densely populated city of Medan (reaching 1,725 tons a day). The river flows in the northeastern area of Sumatra with predominantly tropical rainforest climate (designated as Af in the Köppen-Geiger climate classification). The annual average temperature in the area is 24 °C. The warmest month is January, when the average temperature is around 26 °C, and the coldest is December, at 22 °C. The average annual rainfall
3871-407: The end of their lifespans and can be identified as such by the regular abundance of hair growth and robust cheek pads. The Sumatran orangutan is more social than its Bornean counterpart; groups gather to feed on the mass amounts of fruit on fig trees. The Sumatran orangutan community is best described as loose, not showing social or spatial exclusivity. Groups generally consist of female clusters and
3950-437: The end of this stage, the orangutan will stop sleeping in the mother's nest and will build its own nest nearby. From the ages of 5 to 8 years of age, the orangutan is in an adolescent stage of life. The orangutan weighs around 15–30 kilograms. The light patches on the face start to disappear, and eventually the face becomes completely dark. During this time, orangutans still have constant contact with their mothers, yet they develop
4029-488: The fact that Borneo is home to six or seven times as many orangutans as Sumatra. The comparison has shown these two species diverged around 400,000 years ago, more recently than was previously thought. The orangutan genome also has fewer rearrangements than the chimpanzee/human lineage. Sumatrans encounter threats such as logging (both legal and illegal), wholesale conversion of forest to agricultural land and oil palm plantations, and fragmentation by roads. Oil companies use
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#17327719205414108-593: The forest'. Male Sumatran orangutans grow to about 1.7 m (5.6 ft) tall and 90 kg (200 lb), while females are smaller, averaging 90 cm (3.0 ft) and 45 kg (99 lb). Compared to the Bornean species, Sumatran orangutans are thinner and have longer faces; their hair is longer and has a paler red color. Fossil orangutans in Sumatra from the Pleistocene had similar diets to present day Sumatran orangutans, consisting mainly of soft fruit as evidenced by dental microwear . Compared with
4187-403: The hair around their face shortens, and instead of pointing outwards, the face flattens along the skull. This stage marks sexual maturity in males, yet these orangutans are still socially undeveloped and will still avoid contact with adult males. Finally, male Sumatran orangutans reach adulthood at 13 to 15 years of age. They are extremely large animals, weighing between 50 and 90 kilograms, roughly
4266-513: The headwaters of the Deli is 3,655 hectares, or 7.59 percent of 48 162 hectares of Deli watershed. With an area of 48 162 hectares, length of 73 kilometers (km), and a width of 5.58 m, Deli watershed should have at least 140 hectares, or 30 percent of the watershed. Today, the river is heavily polluted. 70 percent of waste in the Deli River are solid or liquid waste, due to waste generated in
4345-695: The island from the Malay Peninsula , which is an extension of the Eurasian continent. In the southeast, the narrow Sunda Strait , containing the Krakatoa Archipelago , separates Sumatra from Java . The northern tip of Sumatra is near the Andaman Islands , while off the southeastern coast lie the islands of Bangka and Belitung, Karimata Strait and the Java Sea . The Bukit Barisan mountains, which contain several active volcanoes, form
4424-599: The island, in the Aceh Province. Orangutans are rarely, if ever, found south of the Simpang Kanan River on Sumatra's west side or south of the Asahan River on the east side. The Pakpak Barat population in particular is the only Sumatran population predicted to be able to sustain orangutans in the long run, given the current effects of habitat displacement and human impact. While poaching generally
4503-678: The island. Like all parts of Indonesia, Indonesian (which was based on Riau Malay) is the official language and the main lingua franca. Although Sumatra has its own local lingua franca, variants of Malay like Medan Malay and Palembang Malay are popular in North and South Sumatra, especially in urban areas. Minangkabau (Padang dialect) is popular in West Sumatra, some parts of North Sumatra, Bengkulu, Jambi and Riau (especially in Pekanbaru and areas bordered with West Sumatra ) while Acehnese
4582-635: The last 35 years. Many species are now critically endangered , such as the Sumatran ground cuckoo , the Sumatran tiger , the Sumatran elephant , the Sumatran rhinoceros , and the Sumatran orangutan . Deforestation on the island has also resulted in serious seasonal smoke haze over neighbouring countries, such as the 2013 Southeast Asian haze which caused considerable tensions between Indonesia and affected countries Malaysia and Singapore . The widespread deforestation and other environmental destruction in Sumatra and other parts of Indonesia has often been described by academics as an ecocide . Sumatra
4661-643: The main commercial centre of the Aceh Sultanate and trading routes were established to the Mediterranean via the Red Sea to rival the Portuguese shipping lanes . The reign of Iskandar Muda is known as the golden age of Sumatra because he extended the cultural influence of the Aceh Sultanate to Padang and Johor . The Aceh Sultanate sustained the rivalry with the Johor sultanate , the Dutch, and
4740-569: The meat of the slow loris, a nocturnal primate. Water consumption for the orangutans was ingested from natural bowls created in the trees they lived around. They even drank water from the hair on their arms when rainfall was heavy. Meat-eating happens rarely in Sumatran orangutan, and orangutans do not show a male bias in meat-eating. Research in the Ketambe area reported cases of meat-eating in wild Sumatran orangutans, of which nine cases were of orangutans eating slow lorises . The research shows, in
4819-457: The milestone of Kepaksian Sekala Brak in the 13th century AD with the Dalom building. At the same time, the spread of Islam in Indonesia occurred gradually and indirectly, starting from the western regions such as the Sumatra area which became the first place for the spread of Islam in the archipelago, then Java, then to the eastern regions of Indonesia, Sulawesi and Maluku. The island of Sumatra
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#17327719205414898-583: The most recent three cases of slow lorises eaten by Sumatran orangutan, a maximum mean feeding rate of the adult orangutan for an entire adult male slow loris is 160.9 g/h and, of the infant, 142.4 g/h. No cases have been reported during mast years , which suggests orangutans take meat as a fallback for the seasonal shortage of fruits; preying on slow loris occurs more often in periods of low fruit availability. Similar to most primate species, orangutans appear to only share meat between mother and infants. Orangutans have 48 chromosomes . The Sumatran orangutan genome
4977-413: The mother for food, and also sleeps in the mother's nest. The next stage is called juvenilehood and takes place between 2.5 and 5 years of age. The orangutan weighs between 6 and 15 kilograms, and does not look dramatically different from an infant. Although it is still mainly carried by the mother, a juvenile will often play with peers and make small exploratory trips within the vision of the mother. Towards
5056-618: The name for the entire island. By the year 692 , the Melayu Kingdom was absorbed by Srivijaya . Srivijaya's influence waned in the 11th century, specifically in the year 1025, after suffering defeat at the hands of the Chola Empire in southern India By the end of the 12th century, Srivijaya had been reduced to a kingdom, and its dominant role in South Sumatra ended with the last king, Ratu Sekekhummong, who founded
5135-416: The nearby Mentawai Islands . There are about 300 freshwater fish species in Sumatra. There are 93 amphibian species in Sumatra, 21 of which are endemic to Sumatra. The Sumatran tiger , Sumatran rhinoceros , Sumatran elephant , Sumatran ground cuckoo , Sumatran orangutan and Tapanuli orangutan are all critically endangered, indicating the highest level of threat to their survival. In October 2008,
5214-561: The ones connecting Banda Aceh - Lhokseumawe - Besitang - Medan - Tebingtinggi - Pematang Siantar - Rantau Prapat in Northern Sumatra (the Banda Aceh-Besitang section was closed in 1971, but is currently being rebuilt). Padang - Solok - Bukittinggi in West Sumatra , and Bandar Lampung - Palembang - Lahat - Lubuklinggau in Southern Sumatra. Sumatran orangutan The Sumatran orangutan ( Pongo abelii )
5293-417: The orangutans enjoy eating, but they are surrounded by fiberglass-like hairs that are painful if eaten. Tools are created differently for different uses. Sticks are often made longer or shorter depending on whether they will be used for insects or fruits. If a particular tool proves useful, the orangutan will often save it. Over time, they will collect entire "toolboxes". A Neesia -eating orangutan will select
5372-400: The protection of their forest habitat by preventing threats such as deforestation and hunting. The former was determined to be more cost efficient for maintaining the wild orangutan populations, but comes with longer time scale of 10–20 years. The latter approach has better prospects for ensuring long-term stability of populations. This type of habitat conservation approach has been pursued by
5451-456: The question of why the known human cure for Streptococcus was ineffective in this case. The Sumatran orangutan is endemic to the north of Sumatra . In the wild, Sumatran orangutans only survive in the province of Nanggroe Aceh Darussalam (NAD), the northernmost tip of the island. The primate was once more widespread, as they were found farther to the south in the 19th century, such as in Jambi and Padang . There are small populations in
5530-503: The relationship between India and the Indonesian archipelago. In the late 13th century, Marco Polo referred to the kingdom as Samara , while his contemporary fellow Italian traveller Odoric of Pordenone used the form Sumoltra . Later in the 14th century the local form "Sumatra" became popular abroad due to the rising power of the kingdom of Samudera Pasai and the subsequent Sultanate of Aceh . From then on, subsequent European writers mostly used Sumatra or similar forms of
5609-410: The safe environment of captivity. However, this comes at a risk to the Sumatran orangutan's native behaviors in the wild. While in captivity, the orangutans are at risk to the "Captivity Effect": animals held in captivity for a prolonged period will no longer know how to behave naturally in the wild. Being provided with water, food, and shelter while in captivity and lacking all the challenges of living in
5688-473: The same number of inhabitants as South Africa , making it the fifth-most populous island in the world . Yet because it is such a large island, it is not densely populated: it has an average of about 126 people per km . The largest indigenous ethnic groups in Sumatra are Malays, Minangkabaus, Bataks, Acehnese, and Lampungs. Other major non-indigenous ethnic groups are Javanese , Sundanese , and Chinese . Below are 11 largest ethnic groups in Sumatra based on
5767-541: The tenth through thirteenth centuries, in reference to a kingdom near modern-day Banda Aceh which was the first landfall for traders. The island has also been known by other names, including Andalas or Percha Island . Scholars suggest that mention of Suwarnadwipa in the Hindu Epic the Ramayana may be a reference to Sumatra. According to experts on The Ramayana , the epic is one of the first sources to document
5846-489: The weight of a fully grown human. They have a fully grown beard, fully developed cheek callosities, and long hair. These orangutans have reached full sexual and social maturity and now only travel alone. Female Sumatran orangutans typically live 44–53 years in the wild, while males have a slightly longer lifespan of 47–58 years. Females are able to give birth up to 53 years of age, based on studies of menopausal cycles. Both males and females are usually considered healthy even at
5925-490: The wild, captive behaviour becomes more exploratory in nature. A repertoire of 64 different gestures in use by orangutans has been identified, 29 of which are thought to have a specific meaning that can be interpreted by other orangutans the majority of the time. Six intentional meanings were identified: Affiliate/Play, Stop action, Look at/Take object, Share food/object, Co-locomote and Move away. Sumatran orangutans do not use sounds as part of their communication, which includes
6004-609: The world's oldest orangutan in captivity or the wild at the time of her death, died at the Miami MetroZoo at the age of 55. Puan, an orangutan at Perth Zoo , is believed to have been 62 years old at the time of her death, making her the oldest recorded orangutan. The current oldest orangutan in the world is believed to be Bella, a female orangutan at the Hagenbeck Zoo , who is 61 years of age. Sumatran orangutans are primarily frugivores , favoring fruits consisting of
6083-506: Was known in ancient times by the Sanskrit names of Svarṇadvīpa ('Island of Gold') and Svarṇabhūmi ('Land of Gold'), because of the gold deposits in the island's highlands . The earliest known mention of the current form "Sumatra" was in 1017, when the local king Haji Sumatrabhumi ("king of the land of Sumatra") sent an envoy to China . Arab geographers referred to the island as Lamri ( Lamuri , Lambri or Ramni ) in
6162-527: Was sequenced in January 2011 , based on a captive female named Susie. Following humans and chimpanzees , the Sumatran orangutan has become the third extant hominid species to have its genome sequenced. The researchers also published less complete copies from ten wild orangutans, five from Borneo and five from Sumatra . The genetic diversity was found to be lower in Bornean orangutans ( Pongo pygmaeus ) than in Sumatran ones ( Pongo abelii ), despite
6241-435: Was set up here by a Swiss organisation in the 1970s to attempt to rehabilitate orangutans captured from the logging industry. The rangers were trained to teach the orangutans vital jungle skills to enable them to reintegrate into the forest, and provided additional supplementary food from a feeding platform. However, within the last few years, supplementary feeding has ceased as the orangutan rehabilitation program has been deemed
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