Asian Elephant
From Wikipedia, the free encyclopedia
| Asian Elephant[1] | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
  |
||||||||||||||
| Conservation status | ||||||||||||||
| Scientific classification | ||||||||||||||
|
||||||||||||||
| Binomial name | ||||||||||||||
| Elephas maximus Linnaeus, 1758 |
||||||||||||||
 Asian Elephant range
|
The Asian or Asiatic Elephant (Elephas maximus), sometimes known by the name of one of its subspecies (the Indian Elephant), is one of the three living species of elephant, and the only living species of the genus Elephas. The species is found primarily in large parts of Bangladesh,India, Sri Lanka, Indochina and parts of Indonesia. It is considered endangered, with between 25,600 and 32,750 left in the wild[3].
It is smaller than its African relatives; the easiest way to distinguish the two is that the Asian elephant has smaller ears. The Asian Elephant tends to grow to around two to four meters (7–12 feet) in height and 3,000–5,000 kilograms (6,500–11,000 pounds) in weight.
The Asian Elephant has other differences from its African relatives, including a more arched back than the African, one semi-prehensile "finger" at the tip of its trunk as opposed to two, four nails on each hind foot instead of three, and 19 pairs of ribs instead of 21. Also, unlike with the African elephant, the female Asian Elephant usually lacks tusks; if tusks — in that case called "tushes" — are present, they are barely visible, and only seen when the female opens her mouth. Some males may also lack tusks; these individuals are called "makhnas", and are especially common among the Sri Lankan elephant population. Furthermore, the forehead has two hemispherical bulges, unlike the flat front of the African elephant.
This animal is widely domesticated, and has been used in forestry in South and Southeast Asia for centuries and also in ceremonial purposes. Historical sources indicate that they were sometimes used during the harvest season primarily for milling. Wild elephants attract tourist money to the areas where they can most readily be seen, but damage crops, and may enter villages to raid gardens.
Contents |
[edit] Size
The sizes of elephants in the wild have been exaggerated in the past. However, record elephants may have measured as high as 12 feet at the shoulder. Height is often estimated using the rule of thumb of twice the forefoot circumference.[4]
The height of the adult male does not exceed nine feet, and that of the female eight feet; but these dimensions are occasionally considerably exceeded. George P. Sanderson measured a male standing nine feet seven inches at the shoulder, and measuring twenty-six feet two and one-half inches from the tip of the trunk to the extremity of the tail; and he records others respectively reaching nine feet eight inches and nine feet ten inches at the shoulder. An elephant shot by General Kinloch stood upward of ten feet one inch; and another measured by Sanderson ten feet seven and one-half inches. 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: and there is a rumor of a Ceylon elephant of twelve feet. 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 neighborhood of the Rajamahal hills, in Bengal. As now mounted this enormous skeleton stands eleven feet three inches 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.
—Lydekker, 1894 [4]
A record tusk described by George P. Sanderson measured five feet along the curve, with a girth of sixteen inches at the point of emergence from the jaw, the weight being one hundred and four and one-half pounds. This was from an elephant killed by Sir V. Brooke and measured eight feet in length, and nearly seventeen inches in circumference, and weighed ninety pounds. This tusk's weight is, however, exceeded by [the weight of] a shorter tusk of about six feet in length which weighed one hundred pounds.[4]
[edit] Behaviour
In the wild, elephant herds follow well-defined seasonal migration routes. These are made around the monsoon seasons, often between the wet and dry zones, and it is the task of the eldest elephant to remember and follow the traditional migration routes. When human farms are founded along these old routes there is often considerable damage done to crops, and it is common for elephants to be killed in the ensuing conflicts.
Elephants live on average for 60 years in the wild and 80 in captivity.[5] They eat 10% of their body weight each day, which for adults is between 170-200 kilograms of food per day. They need 80–200 litres of water a day, and use more for bathing. They sometimes scrape the soil for minerals.
Elephants use infrasound to communicate; this was first noted by the Indian naturalist M. Krishnan and later studied by Katherine Payne.[6]
[edit] Female behavior
Female elephants live in small groups. They have a matriarchal society, and the group is led by the oldest female. The herd consists of relatives. An individual reaches sexual maturity at 9-15 years of age. 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. Females stay on with the herd, but mature males are chased away.
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.[7][8]
[edit] Male behavior
Bull elephants are usually solitary, and fight over females during the breeding season. Younger bulls may form small groups. Males reach sexual maturity during their 15th year, after which they annually enter "musth". This is a period where the testosterone level is high (up to 60 times greater) and they become extremely aggressive. Secretions containing pheromones occur during this period, from the temporal glands on the forehead.
[edit] Danger
At most seasons of the year the Indian elephant is a timid animal, much more ready to flee from a foe than to make an attack. Solitary rogues are, however, frequently an exception to this rule, and sometimes make unprovoked attacks on passers-by. Rogue elephant sometimes take up a position near a road, and make it impassable to travellers. Females with calves are at all times dangerous to approach. Contrary to what is stated to be the case with the African species, when an Indian elephant makes a charge, it does so with its trunk tightly curled up, and it makes its attack by trampling its victim with its feet or knees, or, if a male, by pinning it to the ground with its tusks. During musth the male elephant is highly dangerous, not only to human beings, but to its fellow animals. At the first indications of this, domestic elephants are secured tightly to prevent any mishaps;[4] xylazine is also used.
While elephant charges are often displays of aggression that do not go beyond threats, some elephants, such as rogues, may actually attack.
In regard to movement on land, Mr. Sanderson says that "the only pace of the elephant is the walk, capable of being increased to a fast shuffle of about fifteen miles an hour for very short distances. It can neither trot, canter, nor gallop. It does not move with the legs on the same side together, but nearly so. A very good runner might keep out of an elephant's way on a smooth piece of turf, but on the ground in which they are generally met with, any attempt to escape by flight, unless supplemented by concealment, would be unavailing."
When an elephant does charge, it requires all the coolness and presence of mind of the sportsman to avoid a catastrophe- "A grander animated object," writes Mr. Sanderson, "than a wild elephant in full charge can hardly be imagined. The cocked ears and broad forehead present an immense frontage; the head is held high, with the trunk curled between the tusks, to be uncoiled in the moment of attack; the massive fore-legs come down with the force and regularity of ponderous machinery; and the whole figure is rapidly foreshortened, and appears to double in size with each advancing stride. The trunk being curled and unable to emit any sound, the attack is made in silence, after the usual premonitory shriek, which adds to its impressiveness. The usual pictorial representations of the Indian elephant charging with upraised trunk are accordingly quite incorrect."[4]
[edit] Captivity
Elephants have been captured from the wild and tamed for use by humans. Their ability to work under instruction makes them particularly useful for carrying heavy objects. They have been used particularly for timber-carrying in jungle areas. Other than their work use, they have been used in war, in ceremonies, and for carriage. They have been used for their ability to travel over difficult terrain by hunters, for whom they served as mobile hunting platforms. The same purpose is met in safaris in modern times.
The first historical record of domestication of Asian elephants was in Harappan times. Ultimately the elephant went on to become a siege engine, a mount in war, a status symbol, a work animal, and an elevated platform for hunting during historical times in South Asia.[9]
The elephant plays an important part in the culture of the subcontinent and beyond, featuring prominently in Jataka tales and the Panchatantra. It plays a major role in Hinduism: the god Ganesha's head is that of an elephant, and the "blessings" of a temple elephant are highly valued. Elephants have been used in processions in Kerala where the animals are adorned with festive outfits. They were also used by almost all armies in India as war elephants, terrifying opponents unused to the massive beast.
[edit] Subspecies
Elephas maximus is the only surviving species in the Elephas genus, although several extinct fossil species of Elephas are known.
There are four subspecies of the Asian elephant:
- Indian Elephant (E. m. indicus)
- Sri Lankan Elephant (E. m. maximus)
- Sumatran Elephant (E. m. sumatrensis)
- Borneo Elephant (E. m. borneensis)
The population in Vietnam and Laos is undergoing tests to determine if it is a fifth subspecies.
E. m. indicus survives in separate ranges in southern India, the Himalayan foothills, and northwest India; it is also found in southern China, Burma, Thailand, Cambodia and the Malaysian peninsula. Most males of this subspecies have tusks.
E. m. maximus is only found in Sri Lanka. It has a larger skull relative to body size, and commonly has a decolourised area of skin on the forehead and the front of the upper trunk. It is rare to find even males with tusks. Males can reach a height of 3.5 metres at the shoulder.
E. m. sumatrensis is only found in Sumatra. It is the second smallest subspecies, between 1.7 to 2.6 metres at the shoulder. It is sometimes called the pocket elephant because of its size.
E. m. borneensis is found in north Borneo (east Sabah and extreme north Kalimantan). It is smaller than all the other subspecies. It has larger ears, a longer tail, and straighter tusks. Genetic tests found that its ancestors separated from the mainland population about 300,000 years ago.[10]
In addition, two extinct subspecies are considered by some authorities to have existed:
- The Chinese population is sometimes separated as E. m. rubridens (pink-tusked elephant); it disappeared after the 14th century BC.
- The Syrian Elephant (E. m. asurus), the westernmost and one of the largest subspecies of the Asian Elephant, went extinct around 100 BC. This latter population, along with other Indian elephants, were considered the best war elephants in antiquity, and found superior to the smallish North African Elephant (Loxodonta africana pharaonensis) used by the armies of Carthage.
[edit] See also
[edit] References
- ^ Shoshani, Jeheskel (November 16, 2005). in Wilson, D. E., and Reeder, D. M. (eds): Mammal Species of the World, 3rd edition, Johns Hopkins University Press, 90. ISBN 0-801-88221-4.
- ^ Asian Elephant Specialist Group (1996). Elephas maximus. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 10 May 2006. Listed as Endangered (EN A1cd v2.3)
- ^ World Wildlife Fund factsheet
- ^ a b c d e Lydekker, R. (1894). The Royal Natural History. Volume 2.
- ^ Asian Elephant - Animal facts (HTML). Retrieved on 2006-06-21.
- ^ Payne, Katherine (1998). Silent Thunder. Simon & Schuster. ISBN 0-684-80108-6.
- ^ Rasmussen, L. E. L., Lee, T. D., Zhang, A. J., Roelofs, W. L. & Daves, G. D. (1997). Purification, identification, concentration and bioactivity of (Z)-7-dodecen-1-yl acetate: sex pheromone of the female Asian elephant, Elephas maximus. Chemical Senses, 22, 417–437.
- ^ Rasmussen, L. E. L., Lee, T. D., Roelofs, W. L., Zhang, A. J. & Daves, G. D. (1996). Insect pheromone in elephants. Nature, 379, 684.
- ^ Rangarajan, M. (2001) India's Wildlife History, pp 6.
- ^ Fernando P, Vidya TNC, Payne J, Stuewe M, Davison G, et al. (2003) DNA Analysis Indicates That Asian Elephants Are Native to Borneo and Are Therefore a High Priority for Conservation. PLoS Biol 1(1): e6 Full text
[edit] External links
- Asian Elephants at the Zoological Gardens of the World
- National Zoo Facts on Asian Elephant and a Webcam of the Asian Elephant exhibit
- The Chaffee Zoo Asian Elephant Fact Sheet
- U.S. Fish & Wildlife Species Profile
|
|
|||||
|---|---|---|---|---|---|
| Kingdom: Animalia · Phylum: Chordata · Class: Mammalia · Infraclass: Eutheria · Superorder: Afrotheria | |||||
| Elephantidae |
|
||||
| Category | |||||
