Borneo () is the third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda Islands, located north of Java, west of Sulawesi, and east of Sumatra. The island is crossed by the equator, which divides it roughly in half. In Indonesia, the island is also known as Kalimantan, which is also the name of the Indonesian region located on the island. The rest of the island consists of East Malaysia and Brunei.
The geology of Borneo was formed beginning in the Mesozoic. It formed part of Sundaland, a region connected to mainland Asia, until it became isolated by sea level rise at the end of the Last Glacial Period. With seven unique ecoregions, including large expanses of some of the oldest tropical rainforests in the world, Borneo is rich in biodiversity and endemic species.
Archaeological evidence indicates that Borneo has been inhabited by humans for tens of thousands of years. The island is home to hundreds of Indigenous communities, cultures and languages, many of which have traditionally been grouped under the broad term "Dayak". Trading settlements on Borneo were connected to regional maritime networks by the first millennium CE.
Several empires, kingdoms and sultanates subsequently emerged around the island's coasts. This includes the Javanese Majapahit, the Sultanate of Brunei, which held influence over much of coastal Borneo and parts of the southern Philippines at its peak in the 15th century, and the Sultanate of Sulu, which became an important maritime power in the Sulu Sea and northeastern Borneo. The island's interior, however, remained politically diverse and was largely governed by numerous Indigenous communities and local systems of authority rather than by a single state. Parts of the island were later colonised by Britain, Netherlands and Japan.
Since decolonisation, Borneo has been politically divided among three sovereign states. Approximately 73% of the island forms part of Indonesia, comprising the five provinces collectively known as Kalimantan. About 26% consists of the Malaysian states of Sabah and Sarawak, while the sovereign state of Brunei occupies a small area on the island's northwestern coast. Brunei is the only sovereign state whose principal territory lies wholly on Borneo; Indonesia and Malaysia both extend far beyond the island. The Malaysian federal territory of Labuan is situated on a small island just off the coast of Borneo.
The majority of Borneo's inhabitants reside in coastal cities. It is the site of Indonesia's planned future capital, Nusantara. Major economic sectors include oil and gas, agriculture, timber and tourism. Industrial deforestation in Indonesian and Malaysian Borneo for timber and agricultural conversion has taken place during the past century.
Etymology Borneo The name Borneo is closely associated with Brunei Darussalam, the historic sultanate and trading polity on the island. Early European travellers and cartographers recorded variants such as Bornei, Burnei, Burneo and Borneo when referring to Brunei, and the name was subsequently applied more broadly to the island. The name may derive from the Sanskrit word (), meaning either "water" or Varuna, the Hindu god of rain and oceans.
The term has been used as early as the late 9th century by Fan Chuo in his book on Nanzhao in the 860s. The term Bóní () was used to describe trading colonies in the south. In 977, Chinese records use the term Bo-ni to refer to Borneo. In 1225, it was also mentioned by the Chinese official Chau Ju-Kua. In modern Chinese, the island is called (), the first two characters being phonetic and the third referring to a large landmass.Wyatt, D. J. (2012:33). The Blacks of Premodern China. United States: University of Pennsylvania Press, Incorporated.
Kalimantan
The Javanese manuscript Nagarakretagama, written by Majapahit court poet Mpu Prapanca in 1365, mentions the island as Nusa Tanjungnagara, which means the "island of the Tanjungpura Kingdom".
When the sixteenth-century Portuguese explorer Jorge de Menezes made contact with the indigenous people of Borneo, they referred to their island as Pulu K'lemantang, and this second word became Kalimantan, the name for modern-day Borneo in the Indonesian language. The term kelamantan is used in Sarawak to refer to a group of people who consume sago in the northern part of the island.
John Crawfurd noted in his 1865 Descriptive Dictionary of the Indian Islands that "(...) Borneo has sometimes been called by the Malays Kalamantan.", which he traces back to the name of a type of mango (Mangifera), though he added that the name, meaning Isle of Mangoes, was little-known and not popular. A mango variety locally called klemantan is still widely found in rural Ketapang and surrounding areas of West Kalimantan.
Another source states that it derives from the Sanskrit word kalamanthana, meaning "burning weather", possibly to describe the island's hot and humid tropical weather. In the Indianized Malay era the name Kalamanthana was derived from the Sanskrit terms kala (time or season) and manthana (churning, kindling, or creating fire by friction), which possibly describes the hot weather.
Geography Geology
Borneo was formed through Mesozoic accretion of microcontinental fragments, ophiolite terranes and island arc crust onto a Paleozoic continental core. At the beginning of the Cenozoic, Borneo formed a promontory of Sundaland which partly separated from Asian mainland by the proto-South China Sea. The oceanic part of the proto-South China Sea was subducted during the Paleogene period and a large accretionary complex formed along the northwestern of the island of Borneo.
In the early Miocene uplift of the accretionary complex occurred as a result of underthrusting of thinned continental crust in northwest. The uplift may have also resulted from shortening due to the counter-clockwise rotation of Borneo between 20 and 10 mega-annum (Ma) as a consequence of Australia–Southeast Asia collision. Large volumes of sediment were shed into basins, which scattered offshore to the west, north and east of Borneo as well into a Neogene basin which is currently exposed in large areas of eastern and southern Sabah.
In southeast Sabah, the Miocene to recent island arc terranes of the Sulu Archipelago extend onshore into Borneo with the older volcanic arc was the result of southeast dipping subduction while the younger volcanics are likely resulted from northwest dipping subduction the Celebes Sea.
Before sea levels rose at the end of the last ice age, Borneo was part of the mainland of Asia, forming, with Java and Sumatra, the upland regions of a peninsula that extended east from present day Indochina. The South China Sea and Gulf of Thailand now submerge the former low-lying areas of the peninsula. Deeper waters separating Borneo from neighbouring Sulawesi prevented a land connection to that island, creating the divide known as Wallace's Line between Asian and Australia-New Guinea biological regions. The island today is surrounded by the South China Sea to the north and northwest, the Sulu Sea to the northeast, the Celebes Sea and the Makassar Strait to the east, and the Java Sea and Karimata Strait to the south. To the west of Borneo are the Malay Peninsula and Sumatra. To the south and east are islands of Indonesia: Java and Sulawesi, respectively. To the northeast are the Philippine Islands. With an area of , it is the third-largest island in the world, and is the largest island of Asia (the largest continent). Its highest point is Mount Kinabalu in Sabah, Malaysia, with an elevation of .
The largest river system is the Kapuas in West Kalimantan, with a length of . Other major rivers include the Mahakam in East Kalimantan ( long), the Barito, Kahayan, and Mendawai in South Kalimantan (, , and long respectively), Rajang in Sarawak ( long) and Kinabatangan in Sabah ( long). Borneo has significant cave systems. In Sarawak, the Clearwater Cave has one of the world's longest underground rivers while Deer Cave is home to over three million bats, with guano accumulated to over deep. The Gomantong Caves in Sabah has been dubbed as the "Cockroach Cave" due to the presence of millions of cockroaches inside the cave. The Gunung Mulu National Park in Sarawak and Sangkulirang-Mangkalihat Karst in East Kalimantan which particularly a karst areas contains thousands of smaller caves.
Ecology
The Borneo rainforest is estimated to be around 140 million years old, making it one of the oldest rainforests in the world. The current dominant tree group, the dipterocarps, has dominated the Borneo lowland rain forests for millions of years. It is the centre of the evolution and distribution of many endemic species of plants and animals, and the rainforest is one of the few remaining natural habitats for the endangered Bornean orangutan. It is an important refuge for many endemic forest species, including the Borneo elephant, the eastern Sumatran rhinoceros, the Bornean clouded leopard, the Bornean rock frog, the hose's palm civet and the dayak fruit bat.
Peat swamp forests occupy the entire coastline of Borneo. The soil of the peat swamp is comparatively infertile, while it is known to be the home of various bird species such as the hook-billed bulbul, helmeted hornbill and rhinoceros hornbill. There are about 15,000 species of flowering plants with 3,000 species of trees (267 species are dipterocarps), 221 species of terrestrial mammals and 420 species of resident birds in Borneo. There are about 440 freshwater fish species in Borneo (about the same as Sumatra and Java combined).Nguyen, T.T.T., and S. S. De Silva (2006). "Freshwater Finfish Biodiversity and Conservation: An Asian Perspective", Biodiversity & Conservation 15(11): 3543–3568 The Borneo river shark is known only from the Kinabatangan River. In 2010, the World Wide Fund for Nature (WWF) stated that 123 species have been discovered in Borneo since the "Heart of Borneo" agreement was signed in 2007.
The WWF has classified the island into seven distinct ecoregions. Most are lowland regions: Borneo lowland rain forests cover most of the island, with an area of . Borneo peat swamp forests Kerangas or Sundaland heath forests Southwest Borneo freshwater swamp forests are found in the island's western and southern lowlands Sunda Shelf mangroves The Borneo montane rain forests lie in the central highlands of the island, above the elevation. The highest elevations of Mount Kinabalu are home to the Kinabalu montane alpine meadows, a subalpine and alpine shrubland notable for its numerous endemic species, including many orchids.
According to analysis of data from Global Forest Watch, the Indonesian portion of Borneo lost of tree cover between 2002 and 2019, of which was primary forest, compared with Malaysian Borneo's of tree cover loss and of primary forest cover loss. As of 2020, Indonesian Borneo accounts for 72% of the island's tree cover, Malaysian Borneo 27%, and Brunei 1%. Primary forest in Indonesia accounts for 44% of Borneo's overall tree cover.
Environmental issues