Asian elephant (Elephas maximus)
Asian elephants (Elephas maximus) are smaller than their African savannah relatives (Loxodonta africana) and have many other physical features that distinguish them. The ears are smaller and the back is more rounded so that the crown of the head is the highest point of the body. One of the characteristic features of an elephant are the modified incisor teeth which are known as tusks, however, only some male Asian elephants have tusks, whilst females (cows) have 'tushes' instead, that are seldom visible. Elephants support their stocky body on stout, pillar-like legs, and the nose and upper lip are joined and elongated into a trunk. The trunk provides a wide variety of functions from feeding, vocalisation, bathing and fighting; those of the Asian elephant have only a single finger-like process on the base, whilst the African elephant has two. The thick, wrinkly skin covering the body is a greyish-brown colour and very dry.
Bull Asian elephants commonly weigh from 4,500 to 5,400 kg (9,900 to 12,000 lb) and are often around 2.7 m (8.9 ft) high at the shoulder. Females typically weigh around 2,000 to 4,000 kg (4,400 to 8,800 lb) and reach an average of 2.4 m (7.9 ft) at the shoulder. Head-and-body length is from 5.5 to 6.4 m (18 to 21 ft), with the tail measuring 1–1.5 m (3.3–4.9 ft) long. The skeleton constitutes about 15% of their body weight. One extraordinarily large bull elephant living in captivity at the Oregon Zoo, weighed 14,500 pounds (6,590 kg) in 2008.
The sizes of wild Asian elephants, especially males, have been exaggerated in the past. Record elephants may have measured as high as 3.7 m (12 ft) at the shoulder. Shoulder height is estimated using the rule of thumb of twice the forefoot circumference.
The height of the adult male usually does not exceed nine feet [2.7 m], and that of the female eight feet [2.4 m]; but these dimensions are occasionally considerably exceeded. George P. Sanderson measured a male standing nine feet seven inches [2.9 m] at the shoulder, and measuring twenty-six feet two and one-half inches [8 m] from the tip of the trunk to the extremity of the tail; and he records others respectively reaching nine feet eight inches [2.9 m] and nine feet ten inches [3 m] at the shoulder. An elephant shot by General Kinloch stood upward of ten feet one inch [3.1 m]; and another measured by Sanderson ten feet seven and one-half inches [3.2 m]. These dimensions are, however, exceeded by a specimen killed by the late Sir Victor Brooke, which is reported to have reached a height of eleven feet [3.4 m]: and there is a rumour of a Ceylon elephant of twelve feet [3.7 m]. That such giants may occasionally exist is indicated by a skeleton in the Museum at Calcutta, which is believed to have belonged to an individual living between 1856 and 1860 in the neighbourhood of the Rajamahal hills, in Bengal. As now mounted this enormous skeleton stands eleven feet three inches [3.4 m] at the shoulders, but Mr. O. S. Fraser, in a letter to the Asian newspaper, states that it is made to stand too low, and that its true height was several inches more. If this be so, there can be no doubt that, when alive, this elephant must have stood fully twelve feet.
The heaviest bull elephant recorded was shot by the Maharajah of Susang in the Garo Hills of Assam, India in 1924, and weighed 8 tonnes (8.8 short tons), stood 3.35 m (11.0 ft) tall and 8.06 m (26.4 ft) long from head to tail.
Asian elephants formerly ranged from West Asia along the
Iranian coast into the Indian subcontinent, eastwards into South-east Asia
including Sumatra, Java, and Borneo, and into China at least as far as the
Yangtze-Kiang. This former range covered over 9 million km² (Sukumar 2003).
Asian elephants are now extinct in West Asia, Java, and most of China The
western populations (Elephas maximus asurus) were probably extinct by 100
BC, and the main Chinese populations (sometimes referred to as E. m.
rubridens) disappeared sometime after the 14th century BC. Even within its
surviving range in South and South-east Asia, the species has been in retreat
for hundreds if not thousands of years, and generally survives only in highly
fragmented populations (Olivier 1978; Sukumar 2003; Blake and Hedges 2004).
Asian elephants still occur in isolated populations in 13 states, with a very approximate total range area of 486,800 km² (Sukumar 2003; but see Blake and Hedges 2004). The species occurs in Bangladesh, Bhutan, India, Nepal, and Sri Lanka in South Asia and Cambodia, China, Indonesia (Kalimantan and Sumatra) Lao PDR, Malaysia (Peninsular Malaysia and Sabah), Myanmar, Thailand, and Vietnam in South-East Asia. Feral populations occur on some of the Andaman Islands (India).
The elephants of Borneo were believed to be feral descendants of elephants introduced in the 14th–19th centuries (Shoshani and Eisenberg, 1982; Cranbrook et al., 2008); however, recent genetic evidence suggests they are indigenous to the island (Fernando et al., 2003; but see Cranbrook et al., 2008).
The species was once found throughout Sri Lanka, but today elephants are restricted mostly to the lowlands in the dry zone where they are still fairly widespread in north, south, east, north-western, north-central and south-eastern Sri Lanka; but with the exceptions of small remnant populations in the Peak Wilderness Area and Sinharaja Area, elephants are absent from the wet zone of the country. The species continues to lose range to development activities throughout the island.
Once widespread in India, the species is now restricted to four general areas: north-eastern India, central India, north-western India, and southern India. In north-eastern India, the elephant range extends from the eastern border of Nepal in northern West Bengal through western Assam along the Himalaya foothills as far as the Mishmi Hills. From here it extends into eastern Arunachal Pradesh, the plains of upper Assam, and the foothills of Nagaland. Further west, it extends to the Garo Hills of Meghalaya through the Khasi Hills, to parts of the lower Brahmaputra plains and Karbi Plateau. Elsewhere in the south in Tripura, Mizoram, Manipur, and the Barak valley districts of Assam, isolated herds occur (Choudhury, 1999). In central India, highly fragmented elephant populations are found in the States of Orissa, Jharkhand, and the southern part of West Bengal, with some animals wandering into Chattisgarh. In north-western India, the species occurs in six fragmented populations at the foot of the Himalayas in Uttaranchal and Uttar Pradesh, ranging from Katerniaghat Wildlife Sanctuary in Bahraich Forest Division in the east, to the Yamuna River in the west. In southern India, elephants occur in the hilly terrain of the Western Ghats and in parts of the Eastern Ghats in the states of Karnataka, Kerala, Tamil Nadu, and, relatively recently, Andhra Pradesh. There are eight main populations in southern India, each fragmented from the others: northern Karnataka; the Crestline of Karnataka–Western Ghats; Bhadra–Malnad; Brahmagiri–Nilgiris–Eastern Ghats; Nilambur–Silent Valley–Coimbatore; Anamalais–Parambikulam; Periyar–Srivilliputhur; and Agasthyamalais.
In Nepal, elephants were once widespread in the lowland Terai, but are now restricted to a few protected areas along the border with India: Royal Chitwan National Park, Parsa Wildlife Reserve, Royal Bardia National Park, and Royal Suklaphanta Wildlife Reserve, and their environs. There is some movement of animals between these protected areas and between Bardia National Park and the adjacent parts of India.
In Bhutan, all the existing elephant populations are found along the border with India. They are reported from Royal Manas National Park, Namgyal Wangchuk Wildlife Sanctuary, Phipsoo Wildlife Sanctuary, and the Reserve Forests such as Khaling Wildlife Sanctuary, Dungsum, and Mochu. In the past, elephants made seasonal migrations from Bhutan to the grasslands of India during the wetter summer months of May to October, returning to their winter range in Bhutan from November. Now these movements are restricted as a result of loss of habitat on the Indian side and fragmentation of habitat on the Bhutan side.
In Bangladesh, the species was once widespread, but today it is largely restricted to areas that are relatively less accessible to humans, mainly Chittagong and the Chittagong Hill Tracts in the southeast. In addition, some animals periodically visit the New Samanbag area of Maulvi Bazar District under the Sylhet Forest Division in the north-east of the country, coming from the neighbouring Indian states of Tripura, Meghalaya, and Assam.
The Asian elephant has a wide, but highly fragmented, distribution in Myanmar. The five main areas of elephant abundance are: the Northern Hill Ranges, the Western Hill Ranges, Pegu Yoma (central Myanmar), Tenasserim Yoma (in the south, bordering Thailand), and Shan State or eastern Yoma.
In Thailand, the species occurs mainly in the mountains along the border with Myanmar, with smaller fragmented populations occurring in the peninsula in the south (in several forest complexes, south to the border with Malaysia); in the northeast (in the Dong Phaya Yen-Khao Yai forest complex, including Khao Yai National Park, and the Phu Khieo-Nam Nao forest complex); and in the east (in a forest complex composing the Khao Ang Runai Wildlife Sanctuary, Khao Soi Dao Wildlife Sanctuary, Khao Khitchakut National Park, and Khao Cha Mao National Park).
In Cambodia, elephants are primarily found in the mountains of the south-west and in Mondulkiri and Ratanakiri Provinces. Recent surveys in Keo Sema District (Mondulkiri Province) suggest that important numbers may remain in that area (WCS unpubl. data). Elsewhere, Asian elephants persist in Cambodia in only small, scattered populations (Duckworth and Hedges, 1998).
In the Lao People’s Democratic Republic, elephants remain widely but very patchily distributed in forested areas, both in the highlands and lowlands. Two important and likely viable populations are known, one in Xaignaboli Province west of the Mekong and one on the Nakai Plateau. Other potentially important elephant populations occur in Phou Phanang and Phou Khao Khoay in Vientiane Province; Phou Xang He in Savannakhet Province; Dong Ampham and Dong Khanthung, including Xe Pian, close to Cambodian border; and Nam Et, Nam Xam, Phou Dendin, and Nam Ha in the north, close to the Viet Namese and Chinese borders.
In Vietnam, only a small population persists now. In the northern part of the country there are no elephants left, barring occasional wanderers into Son La from Lao PDR. In the central and southern parts of the country, very small isolated populations remain in Dak Lak, Nghe An, Quang Nam, Dong Nai, and Ha Tinh Provinces.
In China, Asian elephants once ranged widely over much of southern China, including the Fujiang, Guangdong, and Guangxi Provinces (Smith and MacKinnon, in press). The species was extirpated in southern Fujiang and northern Guangdong during the 12th century, but evidence indicates persistence in Guanxi into the 17th century (Smith and MacKinnon, in press). All that now remains of this once widespread elephant population in China is the remnant in Yunnan where the species survives in three prefectures: Xishuangbanna, Simao, and Lincang.
In Peninsular Malaysia, the species is still widely distributed in the interior of the country in the following States: Pahang (which probably has the largest population), Perak, Johor, Kelantan, Terengganu, Kedah, and Negeri Sembilan (where very few animals remain).
On Borneo, elephants only occur in the lowlands of the north-eastern part of the island in the Malaysian State of Sabah and adjacent parts of Kalimantan (Indonesia). In Sabah, they occur in forested areas in the south, centre, and east of the State in the following Districts: Kinabatangan, Sandakan, Beluran, Lahad Datu, Tawau, and Pensiangan. In Kalimantan, elephants occur only in the Upper Sembakung River in Tindung District. The origin of the elephants of Borneo remains unclear and the subject of debate. Due to the limited distribution of the island’s elephant population it is argued by some that the species was not indigenous, but descended from imported captive elephants (Medway 1977; Cranbrook et al., 2008). However, others argues that while captive elephants have undoubtedly been brought to Borneo, genetic analyses have shown that the elephants found on Borneo are genetically distinct, with molecular divergence indicating a Pleistocene colonization and subsequent isolation (Fernando et al., 2003)
On Sumatra (in Indonesia), the elephant was once widespread, but now survives only in highly fragmented populations. In the mid-1980s, 44 discrete elephant populations were known to exist in Sumatra’s eight provinces, 12 of these were in Lampung Province (Blouch and Haryanto, 1984; Blouch and Simbolon, 1985). However, by 2003, only three of Lampung’s 12 populations were extant (Hedges et al., 2005). An unknown number of Sumatra’s other elephant populations remain (Blake and Hedges, 2004), and those that do are threatened by habitat loss, poaching, and as a result of conflict with humans (Santiapillai and Jackson, 1990; Hedges et al., 2005). Nevertheless, the island is thought to hold some of the most significant populations outside of India. For example, recent surveys in Lampung Province’s two national parks, Bukit Barisan Selatan and Way Kambas, produced population estimates of 498 (95% CI=[373, 666]) and 180 (95% CI=[144, 225]) elephants, respectively (Hedges et al., 2005). Bukit Barisan Selatan NP is therefore a critically important area for Asian elephant conservation. The challenge now is to protect these populations from further habitat loss and poaching.
Bangladesh; Bhutan; Cambodia; China; India; Indonesia (Kalimantan, Sumatera); Lao People's Democratic Republic; Malaysia (Peninsular Malaysia, Sabah); Myanmar; Nepal; Sri Lanka; Thailand; Vietnam
A recent estimate for the global population size of the Asian
elephant was 41,410–52,345 animals Sukumar (2003) The estimated population size
for each country was: Bangladesh 150–250; Bhutan 250–500; Cambodia 250–600;
China 200–250; India 26,390–30,770; Indonesia 2,400–3,400; Lao PDR 500–1,000;
Malaysia 2,100–3,100; Myanmar 4,000–5,000; Nepal 100–125; Sri Lanka 2,500–4,000;
Thailand 2,500–3,200; and Vietnam 70–150 (Sukumar, 2003) . However, Blake
and Hedges (2004) and Hedges (2006) argue that the oft-repeated global
population ‘estimate’ of about 40,000 to 50,000 Asian elephants is no more than
a crude guess, which has been accepted unchanged for a quarter of a century.
They argue that with very few exceptions all we really know about the status of
Asian elephants is the location of some (probably most) populations, with in
some cases a crude idea of relative abundance; and for some large parts of the
species range we do not even know where the populations are, or indeed if they
are still extant. These difference of opinion are due in part to the difficulty
in counting elephants in dense vegetation in difficult terrain, different survey
techniques being used in different places, and a too-widely held belief that
population monitoring is unimportant. Nevertheless, whatever the error margins,
it appears almost certain that over 50% of the remaining wild Asian elephants
occur in India.
The overall population trend of the Asian elephant has been downwards, probably for centuries. This remains the case in most parts of its range, but especially in most of the countries of South-east Asia. Within India, there is evidence that the large population in the Western Ghats in south of the country has been increasing in recent years due to improved conservation effectiveness.
Population Trend: Decreasing
Asian elephants inhabit a wide range of grasslands and forest types, including scrub forest, rainforest and semi-cultivated forests, preferring areas that combine grass with low woody plants and trees.
Ecology and Biology.
Elephants are highly intelligent and long-lived animals; Asian elephants may live as long as 70 years, in captivity. They are extremely sociable and occur in groups of related females, led by the oldest female known as the 'matriarch'. Groups of Asian elephants average six to seven individuals, and will occasionally join with other groups to form herds; although these are more transient than those of African savannah elephants. Males leave their natal group when then reach sexual maturity at around six to seven years of age, after which time they are predominantly solitary. When males reach 20 years old they start coming into 'musth', an extreme state of arousal when levels of testosterone in the blood may increase 20 times. This state lasts about three weeks and during this time the individual will become aggressive and wander widely in search of females. Musth may cause males to fight for access to females and also increases their attractiveness to females. Cows only reach sexual maturity at ten years of age, and the interval between births may be as long as four years owing to the long gestation time and infant dependency. The single calf may suckle from other females in the group as well as their own mother.
Elephants use their dextrous trunk to pluck at grasses and pass them into their mouths; the average daily intake of food is 150 kilograms of vegetation a day. Grasses make up the mainstay of the Asian elephant's diet but scrub and bark are also eaten, and calves may eat their mothers dung to obtain nutrients. Consuming such large quantities of vegetation each day mean that Asian elephants substantially alter their ecosystem by creating new habitats for emergent vegetation. They also defecate up to 18 times per day, which has an important role in dispersing the seeds of many plant species. Where elephants occur near plantations they will readily feed on banana or rice crops. Asian elephants have had a close relationship with man over the centuries; they are still used to clear timber particularly in some of the more inaccessible forests of the continent, and play an important role in the religious and cultural history of the region. Adult females and calves may move about together as groups but adult males disperse from their mothers upon reaching adolescence. Bull elephants may be solitary or form temporary 'bachelor groups.
Cow-calf unit sizes generally tend to be small, typically consisting of 3 adult females who are most likely related, and their offspring; however, larger groups containing as many as 15 adult females may occur. There can also be seasonal aggregations containing over 100 individuals at a time, including calves and sub-adults. Until recently it was thought that Asian elephants, like African elephants, typically follow the leadership of older adult females, or matriarchs. But recently it has been shown that females can form extensive and very fluid social networks, with a lot of individual variation in the degree of gregariousness. Social ties generally tend to be weaker than in African elephants.
Elephants are crepuscular. They are mega herbivores and consume up to 150 kg (330 lb) of plant matter per day. They are generalist feeders, and both grazers and browsers, and were recorded to feed on 112 different plant species, most commonly of the order Malvales, and the legume, palm, sedge and true grass families. They browse more in the dry season with bark constituting a major part of their diet in the cool part of that season.
They drink at least once a day and are never far from a permanent source of fresh water. They need 80–200 litres of water a day and use even more for bathing. At times they scrape the soil for clay or minerals.
Elephants are able to distinguish low amplitude sounds. They use infrasound to communicate; this was first noted by the Indian naturalist M. Krishnan and later studied by Katharine Payne.
A healthy adult Asian elephant is not known to have natural predators, but there have been rare instances of tigers preying on young or weak elephants. Bulls will fight one another to get access to estrus females. Strong fights over access to females are extremely rare. Bulls reach sexual maturity around the age of 12–15. Between the age of 10 to 20 years, bulls undergo an annual phenomenon known as "musth". This is a period where the testosterone level is up to 100 times greater than non-musth periods, and they become extremely aggressive. Secretions containing pheromones occur during this period, from the paired temporal glands located on the head between the lateral edge of the eye and the base of the ear.
The gestation period is 18–22 months, and the female gives birth to one calf, or occasionally twins. The calf is fully developed by the 19th month but stays in the womb to grow so that it can reach its mother to feed. At birth, the calf weighs about 100 kg (220 lb), and is suckled for up to 2–3 years. Once a female gives birth, she usually does not breed again until the first calf is weaned, resulting in a 4–5-year birth interval. Females stay on with the herd, but mature males are chased away
Elephants' life expectancy have been exaggerated in the past; they live on average for 60 years in the wild and 80 in captivity.
Females produce sex pheromones; a principal component thereof, (Z)-7-dodecen-1-yl acetate, has also been found to be a sex pheromone in numerous species of insects.
Asian elephants are highly intelligent and self-aware. They have a very large and highly convoluted neocortex, a trait also shared by humans, apes and certain dolphin species. Asian elephants have the greatest volume of cerebral cortex available for cognitive processing of all existing land animals. Elephants have a volume of cerebral cortex available for cognitive processing that exceeds that of any primate species, and extensive studies place elephants in the category of great apes in terms of cognitive abilities for tool use and tool making. Elephants are reported to go to safer ground during natural disasters like tsunamis and earthquakes, although there have been no scientific records of this.
Numbers of Asian elephants were decimated by habitat loss and hunting throughout their historical range. Vast tracts of land have been logged or simply cleared to accommodate the growing human population in the region. Such disturbance from infrastructure development can also cause increased stress and confusion amongst elephants. Elephant populations have become increasingly isolated in the fragmented habitat that remains, often coming into conflict with local farmers. Crops are damaged and lives lost; up to 300 people a year are killed by elephants in India, leading to retaliation on local elephants. Poaching for ivory is also a threat and because only males have tusks, populations can become extremely skewed towards females, thus affecting breeding rates.
The pre-eminent threats to the Asian elephant today are
habitat loss, degradation, and fragmentation (Leimgruber et al., 2003; Sukumar,
2003; Hedges, 2006), which are driven by an expanding human population, and lead
in turn to increasing conflicts between humans and elephants when elephants eat
or trample crops. Hundreds of people and elephants are killed annually as a
result of such conflicts. The long-term future of elephants outside protected
areas, as well as in some protected areas, is therefore inextricably linked to
mitigating such human–elephant conflicts, and this is one of the largest
conservation challenges in Asia today (Sukumar, 1992, 2003; Hedges 2006).
Asian elephants live in the region of the world with the densest human population, growing at a rate of between 1–3% per year. Because elephants require much larger areas of natural habitat than most other terrestrial mammals in Asia, they are one of the first species to suffer the consequences of habitat fragmentation and destruction and because of its great size and large food requirements, the elephant cannot co-exist with people in areas where agriculture is the dominant form of land-use. In extreme cases, elephants have been confined as so called ‘pocketed herds’ in small patches of forest in landscapes dominated by man. Such ‘pocketed herds’ represent an extreme stage in the human–elephant conflict (Olivier, 1978). In other cases elephants have been caught and taken to so-called Elephant Training Centres where they languish, lost to the wild population (Hedges et al., 2005, 2006).
Poaching is a major threat to elephants in Asia too, although reliable estimates of the number of elephants killed and the quantities of ivory and other body parts collected and traded are scarce (Sukumar et al., 1998; Milliken, 2005). It has been argued that poaching is a relatively minor threat to Asian elephant because some males and all females lack tusks (Dawson and Blackburn, 1991). However, the reality is that elephants are poached for a variety of other products (including meat and leather) in addition to ivory, and poaching is now acknowledged as a threat to the long-term survival of some Asian elephant populations (e.g. Kemf and Santiapillai, 2000; Menon, 2002). Moreover, poaching of elephants for ivory is a serious problem in some parts of Asia (Sukumar, 1992; Menon et al., 1997). In Periyar Tiger Reserve in southern India, for example, ivory poaching has dramatically skewed adult sex ratios: over the 20-year period from 1969 to 1989 the adult male: female sex ratio changed from 1:6 to 1:122 (Chandran, 1990). Selective removal of tusked males has several implications for the affected populations: sex ratios obviously become highly female biased, genetic variation is reduced, and fecundity and recruitment may decline (Sukumar et al., 1998; Sukumar, 2003). Poaching of elephants is also a major problem in other parts of Asia. Large-scale hunting of elephants for ivory, bush meat, hides, and other products has reduced their populations significantly over a wide area from Myanmar to Indonesia (Menon et al., 1997; Duckworth and Hedges, 1998; Kemf and Santiapillai, 2000; Martin and Stiles, 2002; Menon, 2002; World Wide Fund for Nature, 2002a; Hedges et al., 2005).
This species is listed on CITES Appendix I. The most important conservation priorities for the Asian elephant are: 1) conservation of the elephant's habitat and maintaining habitat connectivity by securing corridors; 2) the management of human–elephant conflicts as part of an integrated land-use policy that recognizes elephants as economic assets from which local people need to benefit or at least no suffer; 3) better protection to the species through improved legislation and law enforcement, improved and enhanced field patrolling, and regulating/curbing trade in ivory and other elephant products. Monitoring of conservation interventions is also needed to assess the success or failure of the interventions so that adjustments can be made as necessary (i.e. adaptive management). Reliable estimation of population size and trends will be needed as part of this monitoring and adaptive management approach.