Asian elephant


The Asian elephant, 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 process; 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 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

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 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, occurs in Borneo's northeastern parts, primarily in Sabah, and sometimes in Kalimantan. 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:
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 and spread throughout Africa before expanding into the southern half of Asia. The earliest Elephas species, Elephas ekorensis, is known from the Early Pliocene of East Africa, around 5–4.2 million years ago. The oldest remains of the genus in Asia are known from the Siwalik Hills in the Indian subcontinent, dating to the late Pliocene, around 3.6 to 3.2 million years ago, assigned to the species Elephas planifrons. The modern Asian elephant is suggested to have evolved from the species Elephas hysudricus, which first appeared at the beginning of the Early Pleistocene around 2.6 million years ago, and is primarily known from remains of Early-Middle Pleistocene age found on the Indian subcontinent. Skeletal remains of E. m. asurus have been recorded from the Middle East: Iran, Iraq, Syria, and Turkey from periods dating between at least 1800 BC and likely 700 BC.

Description

In general, the Asian elephant is smaller than the African bush elephant and has the highest body point on the head. The back is convex or level. The ears are small with dorsal borders folded laterally. It has up to 20 pairs of ribs and 34 caudal vertebrae. The feet have five nail-like structures on each forefoot, and four on each hind foot. The forehead has two hemispherical bulges, unlike the flat front of the African elephants. Its long trunk or proboscis has only one fingerlike tip, in contrast to the African elephants, which have two. Hence, the Asian species relies more on wrapping around a food item and squeezing it into its mouth, rather than grasping with the tip. Asian elephants have more muscle coordination and can perform more complex tasks.Cows usually lack tusks; if tusks—in that case, called "tushes"—are present, they are barely visible and only seen when the mouth is open. The enamel plates of the molars are greater in number and closer together in Asian elephants. Some bulls may also lack tusks; these individuals are called "makhnas" and are especially common among the Sri Lankan elephant population. A tusk from an tall elephant killed by Sir Victor Brooke measured in length, and nearly in circumference, and weighed. This tusk's weight is, however, exceeded by the weight of a shorter tusk of about in length, which weighed, and there have reportedly been tusks weighing over.
Skin colour is usually grey, and may be masked by soil because of dusting and wallowing. Their wrinkled skin is movable and contains many nerve centres. It is smoother than that of African elephants and may be depigmented on the trunk, ears, or neck. The epidermis and dermis of the body average thick; skin on the dorsum is thick providing protection against bites, bumps, and adverse weather. Its folds increase surface area for heat dissipation. They can tolerate cold better than excessive heat. Skin temperature varies from. Body temperature averages.

Size

On average, when fully-grown, bulls are about tall at the shoulder and in weight, while cows are smaller at about at the shoulder and in weight. Sexual dimorphism in body size is relatively less pronounced in Asian elephants than in African bush elephants; with bulls averaging 15% and 23% taller in the former and latter respectively. Length of body and head including trunk is with the tail being long. The largest bull elephant ever recorded was shot by the Maharajah of Susang in the Garo Hills of Assam, India, in 1924, it weighed an estimated, stood tall at the shoulder and was long from head to tail. The Raja Gaj elephant in Bardia National Park was estimated to be tall at the shoulder and one of the biggest Asian bull elephants. There are reports of larger individuals as tall as and, and long from head to tail.

Distribution and habitat

Asian elephants are distributed throughout 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. They inhabit grasslands, tropical evergreen forests, semi-evergreen forests, moist deciduous forests, dry deciduous forests and dry thorn forests, in addition to cultivated and secondary forests and scrublands. Over this range of habitat types elephants occur from sea level to over. In the eastern Himalaya in northeast India, they regularly move up above in summer at a few sites.
In Bangladesh, some isolated populations survived in the south-east Chittagong Hills in the early 1990s. In Malaysia's northern Johor and Terengganu National Park, two Asian elephants tracked using satellite tracking technology spent most of their time in secondary or "logged-over forest"; they travelled 75% of their time in an area less than away from a water source. In China, the Asian elephant survives only in the prefectures of Xishuangbanna, Simao and Lincang of southern Yunnan., the estimated population was around 300 individuals.
As of 2017, the estimated wild population in India account for nearly three-fourths of the extant population, at 27,312 individuals. In 2019, the Asian elephant population in India increased to an estimated 27,000–29,000 individuals., the global wild population was estimated at 48,323–51,680 individuals.