الفارس الشمري
28-04-2010, 06:59 PM
A report on
Elephants
2009/2010
Student :
Teacher :
Grade :
Elephants are large land mammals in two genera of the family Elephantidae: Elephas and Loxodonta. Three species of elephant are living today: the African Bush Elephant, the African Forest Elephant and the Asian Elephant (also known as the Indian Elephant). All other species and genera of Elephantidae are extinct, some since the last ice age: dwarf forms of mammoths may have survived as late as BC. 1 Elephants and other Elephantidae were once classified with other thick-skinned animals in a now invalid order, Pachydermata.
Elephants are the largest land animals now living. The elephant's gestation period is 22 months, the longest of any land animal. At birth it is common for an elephant calf to weigh 120 kilograms (260 lb). They typically live for 50 to 70 years, but the oldest recorded elephant lived for 82 years. The largest elephant ever recorded was shot in Angola in 1956. This male weighed about 12,000 kilograms (26,000 lb), with a shoulder height of 4.2 metres (14 ft), a metre (yard) taller than the average male African elephant. The smallest elephants, about the size of a calf or a large pig, were a prehistoric species that lived on the island of Crete during the Pleistocene epoch.
The elephant has appeared in cultures across the world. They are a symbol of wisdom in Asian cultures and are famed for their memory and intelligence, where they are thought to be on par with cetaceans and hominids. Aristotle once said the elephant was "the beast which passeth all others in wit and mind". The word "elephant" has its origins in the Greek ἐλέφας, meaning "ivory" or "elephant".
Healthy adult elephants have no natural predators, although lions may take calves or weak individuals. They are, however, increasingly threatened by human intrusion and poaching. Once numbering in the millions, the African elephant population has dwindled to between 470,000 and 690,000 individuals according to a March 2007 estimate. While the elephant is a protected species worldwide, with restrictions in place on capture, domestic use, and trade in products such as ivory, CITES reopening of "one time" ivory stock sales, has resulted in increased poaching. Certain African
nations report a decrease of their elephant populations by as much as two-thirds, and populations in certain protected areas are in danger of being eliminated. Since recent poaching has increased by as much as 45%, the current population is unknown (2008).
Taxonomy and evolution:
The African Elephant genus contains two (or, arguably, three) living species; whereas the Asian Elephant species is the only surviving member of the Asian Elephant genus, but can be divided into four subspecies. The African and the Asian elephant diverged from a common ancestor some 7.6 million years ago.
African Elephant:
The African elephant, Loxodonta Africana, have a straight back, enormous ears, and two trunk 'fingers'. 2fingerscloseupAfrican elephants are named for the peculiar shaped ridges of their molar teeth; the ridges of an African elephant's teeth are coarser and fewer than those of the Asian elephant.The African elephant has only four toes on the front feet and three on the back. Interestingly, it has one more vertebra in the lumbar section of the spine.XXXX sexes have tusks, and they are also larger in size as compared to male and female Asian elephants.The largest African elephant recorded weighed over nine tons and stood more than twelve feet high at the shoulder. As in Asian elephants, the female African elephant is generally half the size of a fully grown male.Gestation period tends to be slightly longer than in the Asian elephant.
Asian Elephant:
The Asian elephant, Elephas Maximus, has an enormous domed head with relatively small ears, an arched back and a single finger like protuberance that is located at the tip of the trunk. An Asian elephant has five toes on the front of the feet and and four on the back.
A large bull could typically weighs six tons and is ten feet high at the shoulder. As with gorillas, there is a large degree of sexual dimorphism between males and females in Asian Elephants where adult females are about half the size of the largest males.
The males have tusks and the females have 'tushes', which are shore second incisors that just stick out beyond the upper lip. However, it is important to note that on occasion females some times have longer tushes than described. The gestation period is between nineteen and twenty-two months. Periodically, it is noted that male infants typically have a slightly longer term than females.
Harvest from the wild
The harvest of elephants, XXXX legal and illegal, has had some unexpected consequences on elephant anatomy as well. African ivory hunters, by killing only tusked elephants, have given a much larger chance of mating to elephants with small tusks or no tusks at all. The propagation of the absent-tusk gene has resulted in the birth of large numbers of tuskless elephants, now approaching 30% in some populations (compare with a rate of about 1% in 1930). Tusklessness, once a very rare genetic abnormality, has become a widespread hereditary trait.
Elephants are ubiquitous in Western popular culture as emblems of the exotic because their unique appearance and size sets them apart from other animals and because, like other African animals such as the giraffe, rhinoceros, and hippopotamus, they are unfamiliar to Western audiences. Popular culture's stock references to elephants rely on this exotic uniqueness. For instance, a "white elephant" is a byword for something expensive, useless and bizarre.
References:
- ^ S. L. Vartanyan*, V. E. Garutt† & A. V. Sher‡parallel, "Holocene dwarf mammoths from Wrangel Island in the Siberian Arctic", Nature 362, 337 - 340 (25 March 1993) Nature.com.
- ^ "African Elephant". National Geographic. African Elephants, African Elephant Pictures, African Elephant Facts - National Geographic (http://www3.nationalgeographic.com/animals/mammals/african-elephant.html). Retrieved 2007-06-16.
- Elephant - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Elephant).
Elephants
2009/2010
Student :
Teacher :
Grade :
Elephants are large land mammals in two genera of the family Elephantidae: Elephas and Loxodonta. Three species of elephant are living today: the African Bush Elephant, the African Forest Elephant and the Asian Elephant (also known as the Indian Elephant). All other species and genera of Elephantidae are extinct, some since the last ice age: dwarf forms of mammoths may have survived as late as BC. 1 Elephants and other Elephantidae were once classified with other thick-skinned animals in a now invalid order, Pachydermata.
Elephants are the largest land animals now living. The elephant's gestation period is 22 months, the longest of any land animal. At birth it is common for an elephant calf to weigh 120 kilograms (260 lb). They typically live for 50 to 70 years, but the oldest recorded elephant lived for 82 years. The largest elephant ever recorded was shot in Angola in 1956. This male weighed about 12,000 kilograms (26,000 lb), with a shoulder height of 4.2 metres (14 ft), a metre (yard) taller than the average male African elephant. The smallest elephants, about the size of a calf or a large pig, were a prehistoric species that lived on the island of Crete during the Pleistocene epoch.
The elephant has appeared in cultures across the world. They are a symbol of wisdom in Asian cultures and are famed for their memory and intelligence, where they are thought to be on par with cetaceans and hominids. Aristotle once said the elephant was "the beast which passeth all others in wit and mind". The word "elephant" has its origins in the Greek ἐλέφας, meaning "ivory" or "elephant".
Healthy adult elephants have no natural predators, although lions may take calves or weak individuals. They are, however, increasingly threatened by human intrusion and poaching. Once numbering in the millions, the African elephant population has dwindled to between 470,000 and 690,000 individuals according to a March 2007 estimate. While the elephant is a protected species worldwide, with restrictions in place on capture, domestic use, and trade in products such as ivory, CITES reopening of "one time" ivory stock sales, has resulted in increased poaching. Certain African
nations report a decrease of their elephant populations by as much as two-thirds, and populations in certain protected areas are in danger of being eliminated. Since recent poaching has increased by as much as 45%, the current population is unknown (2008).
Taxonomy and evolution:
The African Elephant genus contains two (or, arguably, three) living species; whereas the Asian Elephant species is the only surviving member of the Asian Elephant genus, but can be divided into four subspecies. The African and the Asian elephant diverged from a common ancestor some 7.6 million years ago.
African Elephant:
The African elephant, Loxodonta Africana, have a straight back, enormous ears, and two trunk 'fingers'. 2fingerscloseupAfrican elephants are named for the peculiar shaped ridges of their molar teeth; the ridges of an African elephant's teeth are coarser and fewer than those of the Asian elephant.The African elephant has only four toes on the front feet and three on the back. Interestingly, it has one more vertebra in the lumbar section of the spine.XXXX sexes have tusks, and they are also larger in size as compared to male and female Asian elephants.The largest African elephant recorded weighed over nine tons and stood more than twelve feet high at the shoulder. As in Asian elephants, the female African elephant is generally half the size of a fully grown male.Gestation period tends to be slightly longer than in the Asian elephant.
Asian Elephant:
The Asian elephant, Elephas Maximus, has an enormous domed head with relatively small ears, an arched back and a single finger like protuberance that is located at the tip of the trunk. An Asian elephant has five toes on the front of the feet and and four on the back.
A large bull could typically weighs six tons and is ten feet high at the shoulder. As with gorillas, there is a large degree of sexual dimorphism between males and females in Asian Elephants where adult females are about half the size of the largest males.
The males have tusks and the females have 'tushes', which are shore second incisors that just stick out beyond the upper lip. However, it is important to note that on occasion females some times have longer tushes than described. The gestation period is between nineteen and twenty-two months. Periodically, it is noted that male infants typically have a slightly longer term than females.
Harvest from the wild
The harvest of elephants, XXXX legal and illegal, has had some unexpected consequences on elephant anatomy as well. African ivory hunters, by killing only tusked elephants, have given a much larger chance of mating to elephants with small tusks or no tusks at all. The propagation of the absent-tusk gene has resulted in the birth of large numbers of tuskless elephants, now approaching 30% in some populations (compare with a rate of about 1% in 1930). Tusklessness, once a very rare genetic abnormality, has become a widespread hereditary trait.
Elephants are ubiquitous in Western popular culture as emblems of the exotic because their unique appearance and size sets them apart from other animals and because, like other African animals such as the giraffe, rhinoceros, and hippopotamus, they are unfamiliar to Western audiences. Popular culture's stock references to elephants rely on this exotic uniqueness. For instance, a "white elephant" is a byword for something expensive, useless and bizarre.
References:
- ^ S. L. Vartanyan*, V. E. Garutt† & A. V. Sher‡parallel, "Holocene dwarf mammoths from Wrangel Island in the Siberian Arctic", Nature 362, 337 - 340 (25 March 1993) Nature.com.
- ^ "African Elephant". National Geographic. African Elephants, African Elephant Pictures, African Elephant Facts - National Geographic (http://www3.nationalgeographic.com/animals/mammals/african-elephant.html). Retrieved 2007-06-16.
- Elephant - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Elephant).