Asian elephant

The Asian elephant (''Elephas maximus''), also known as the Asiatic elephant, is the only living ''Elephas'' species. It is the largest living land animal in Asia and the second largest living elephantid in the world. It is characterised by its long trunk with a single finger-like processing; large tusks in males; laterally folded large ears and wrinkled grey skin that is partly depigmented on the trunk, ears or neck. Adult males average in weight and females . It has a large and well developed neocortex of the brain, is highly intelligent and self-aware being able to display behaviours associated with grief, learning and greeting. Three subspecies are recognised—'' E. m. maximus'', ''E. m. indicus'' and '' E. m. sumatranus''.

The Asian elephant is distributed in the Indian subcontinent and Southeast Asia, from India in the west to Borneo in the east, and Nepal in the north to Sumatra in the south. It frequently inhabits grasslands,  tropical evergreen forests, semi-evergreen forests, moist deciduous forests, dry deciduous forests and dry thorn forests. It is herbivorous, eating about of vegetation per day. Cows and calves form groups, while males remain solitary or form "bachelor groups" with other males. During the breeding season, males temporarily join female groups to mate. Wild Asian elephants live to be about 60 years old. While female captive elephants are recorded to have lived beyond 60 years when kept in semi-natural surroundings, Asian elephants die at a much younger age in captivity; captive populations are declining due to a low birth and high death rate.

Since 1986, the Asian elephant has been listed as Endangered on the IUCN Red List, as the population has declined by at least 50 per cent over the last three elephant generations, which is about 60–75 years. It is primarily threatened by loss of habitat, habitat degradation, fragmentation and poaching. The earliest indications of captive use of Asian elephants are engravings on seals of the Indus Valley civilisation dated to the 3rd millennium BC.

Taxonomy

Carl Linnaeus proposed the scientific name ''Elephas maximus'' in 1758 for an elephant from Ceylon. ''Elephas indicus'' was proposed by Georges Cuvier in 1798, who described an elephant from India. Coenraad Jacob Temminck named an elephant from Sumatra ''Elephas sumatranus'' in 1847. Frederick Nutter Chasen classified all three as subspecies of the Asian elephant in 1940. These three subspecies are currently recognised as valid taxa. Results of phylogeographic and morphological analyses indicate that the Sri Lankan and Indian elephants are not distinct enough to warrant classification as separate subspecies.

Three subspecies are recognised:

* Sri Lankan elephant (''E. maximus maximus'' )
* Indian elephant (''E. maximus indicus'' )
* Sumatran elephant (''E. maximus sumatranus'' )

Sri Lankan elephants are the largest subspecies. Their skin colour is darker than of ''E. m. indicus'' and of ''E. m. sumatranus'' with larger and more distinct patches of depigmentation on ears, face, trunk and belly. The skin color of the Indian elephant is generally grey and lighter than that of ''E. m. maximus'' but darker than that of ''E. m. sumatranus''.

A potential fourth subspecies, the Borneo elephant (''Elephas maximus borneensis''), occurs in Borneo's northeastern parts, primarily in Sabah (Malaysia), and sometimes in Kalimantan (Indonesia). It was proposed by Paules Deraniyagala in 1950, who described an elephant in an illustration published in the ''National Geographic'' magazine, but not as a living elephant in accordance with the rules of the International Code of Zoological Nomenclature. These elephants living in northern Borneo are smaller than all the other subspecies, but had larger ears, a longer tail, and straight tusks. Results of genetic analysis indicate that their ancestors separated from the mainland population about 300,000 years ago. A study in 2003, using mitochondrial DNA analysis and microsatellite data, indicated that the Borneo elephant population is derived from stock that originated in the region of the Sunda Islands, and suggests that the Borneo population has been separated from the other elephant populations of southeast Asia since the Pleistocene.

The following Asian elephants were proposed as extinct subspecies, but are now considered synonymous with the Indian elephant:

* Syrian elephant (''E. m. asurus''), proposed by Deraniyagala, based on fossil remains and Bronze Age illustrations.
* Chinese elephant (''E. m. rubridens''), also proposed by Deraniyagala, based on a Chinese bronze statuette.
* Javan elephant (''E. m. sondaicus''), also proposed by Deraniyagala, based on an illustration of a carving on the Buddhist monument of Borobudur.

Evolution

The genus ''Elephas'', of which the Asian elephant is the only living member, is the closest relative of the extinct mammoths. The two groups are estimated to have split from each other around 7 million years ago.
''Elephas'' originated in Sub-Saharan Africa during the Pliocene