Post by DinosaurMichael on Feb 27, 2012 20:23:20 GMT -5
African Bush Elephant - Loxodonta africana
The African Bush Elephant or African Savanna Elephant (Loxodonta africana) is the larger of the two species of African elephant. Both it and the African Forest Elephant have usually been classified as a single species, known simply as the African Elephant. Some authorities still consider the currently available evidence insufficient for splitting the African Elephant into two species. It is also known as the Bush Elephant. The African Elephant is the largest living terrestrial animal, normally reaching 6 to 7.3 metres (19.7 to 24.0 ft) in length and 3.5 to 4 metres (11.5 to 13.1 ft) in height at the head, and weighing between 6,000 to 9,000 kg (13,000 to 20,000 lb). The largest on record, shot in Angola in 1955, was a bull weighing 12,274 kg (27,060 lbs and standing 4.2 metres (13.8 ft) high, the body of which is now mounted in the rotunda of the National Museum of Natural History in Washington, D.C.. (The museum's website states that the specimen weighs only 8 tons.) The Bush Elephant normally moves at a rate of 6 km/h (4 mph), but it can reach a top speed of 40 km/h (25 mph) when scared or upset. The animal is characterized by its large head; two large ears that cover its shoulders and radiate excess heat; a large and muscular trunk; two prominent tusks, which are well-developed in both sexes, although more commonly in males; a short neck; a large, barrel-like body; four long and heavy legs; and a relatively short tail. The animal is protected by a heavy but flexible layer of gray-brown skin, dotted with mostly undeveloped patches of hair and long, black hair at the tip of its tail. Its back feet have three toes that form a hoof, while the number of toes on the front feet have varied between four and five. The forehead is smoother and less convex than that of the Asian Elephant. The trunk is the most characteristic feature of the African Bush Elephant. It is formed by the fusion and elongation of the nose and upper lip, forming a flexible and strong organ made purely of muscle. Little scientific research has been carried out into elephants' cognitive or perceptual abilities. An exception is a recent report that African Bush Elephants are able to use seismic vibrations at infrasound frequencies for communication.
Woolly Mammoth - Mammuthus primigenius
The woolly mammoth (Mammuthus primigenius), also called the tundra mammoth, is a species of mammoth. This animal is known from bones and frozen carcasses from northern North America and northern Eurasia with the best preserved carcasses in Siberia. They are perhaps the most well known species of mammoth. This mammoth species was first recorded in (possibly 150,000 years old) deposits of the second last glaciation in Eurasia. It was derived from the steppe mammoth (Mammuthus armeniacus). It disappeared from most of its range at the end of the Pleistocene (10,000 years ago), with an isolated population still living on Wrangel Island until roughly 1700 BC. Woolly mammoths are common in the fossil record. Unlike most other prehistoric animals, their remains are often not literally fossilised - that is, turned into stone - but rather are preserved in their organic state. This is due in part to the frozen climate of their habitats, and to their massive size. Woolly mammoths are therefore among the best-understood prehistoric vertebrates known to science in terms of anatomy. Woolly mammoths lived in two groups which are speculated to be divergent enough to be characterised as subspecies. One group stayed in the middle of the high Arctic, while the other group had a much wider range. The Bering Land Bridge likely played an important role in structuring woolly mammoth populations, acting as an ecological barrier. Recent stable isotope studies of Siberian and New World mammoths has shown there were also differences in climatic conditions on either side of the Bering Land Bridge, with Siberia being more uniformly colder and drier throughout the Late Pleistocene. Woolly mammoths were not noticeably larger than present-day African elephants. Fully grown mammoth bulls reached heights between 2.8 m (9.2 ft) and 3.0 m (9.8 ft) while the dwarf varieties reached between 1.8 m (5.9 ft) and 2.3 m (7.5 ft). Woolly mammoths had a number of adaptations to the cold, most famously the thick layer of shaggy hair, up to 1 meter in length, with a fine underwool, for which the woolly mammoth is named. The coats were similar to those of muskoxen, and it is likely mammoths moulted in summer. They also had far smaller ears than modern elephants; the largest mammoth ear found so far was only 30 cm (12 in) long, compared to 180 cm (71 in) for an African elephant. Their skin was no thicker than that of present-day elephants, but unlike elephants, they had numerous sebaceous glands in their skin which secreted greasy fat into their hair, improving its insulating qualities. They had a layer of fat up to 8 cm (3.1 in) thick under the skin which, like the blubber of whales, helped to keep them warm. Similar to reindeer and musk oxen, their haemoglobin was adapted to the cold, with three genetic mutations to improve oxygen delivery around the body and prevent freezing. Other characteristic features included a high, peaked head that appears knob-like in many cave paintings, and a high shoulder hump resulting from long spinous processes on the neck vertebrae that probably carried fat deposits. Another feature at times found in cave paintings was confirmed by the discovery of the nearly intact remains of a baby mammoth named Dima. Unlike the trunk lobes of living elephants, Dima's upper lip at the tip of the trunk had a broad lobe feature, while the lower lip had a broad, squarish flap. Their teeth were also adapted to their diet of coarse tundra grasses, with more plates and a higher crown than their southern relatives. Woolly mammoths had extremely long tusks — up to 5 m (16 ft) long — which were markedly curved, to a much greater extent than those of elephants. It is not clear whether the tusks were a specific adaptation to their environment; mammoths may have used their tusks as shovels to clear snow from the ground and reach the vegetation buried below. This is evidenced by flat sections on the ventral surface of some tusks. It has also been observed in many specimens that there may be an amount of wear on top of the tusk that would suggest some animals had a preference as to which tusk on which they rested their trunks.
The African Bush Elephant or African Savanna Elephant (Loxodonta africana) is the larger of the two species of African elephant. Both it and the African Forest Elephant have usually been classified as a single species, known simply as the African Elephant. Some authorities still consider the currently available evidence insufficient for splitting the African Elephant into two species. It is also known as the Bush Elephant. The African Elephant is the largest living terrestrial animal, normally reaching 6 to 7.3 metres (19.7 to 24.0 ft) in length and 3.5 to 4 metres (11.5 to 13.1 ft) in height at the head, and weighing between 6,000 to 9,000 kg (13,000 to 20,000 lb). The largest on record, shot in Angola in 1955, was a bull weighing 12,274 kg (27,060 lbs and standing 4.2 metres (13.8 ft) high, the body of which is now mounted in the rotunda of the National Museum of Natural History in Washington, D.C.. (The museum's website states that the specimen weighs only 8 tons.) The Bush Elephant normally moves at a rate of 6 km/h (4 mph), but it can reach a top speed of 40 km/h (25 mph) when scared or upset. The animal is characterized by its large head; two large ears that cover its shoulders and radiate excess heat; a large and muscular trunk; two prominent tusks, which are well-developed in both sexes, although more commonly in males; a short neck; a large, barrel-like body; four long and heavy legs; and a relatively short tail. The animal is protected by a heavy but flexible layer of gray-brown skin, dotted with mostly undeveloped patches of hair and long, black hair at the tip of its tail. Its back feet have three toes that form a hoof, while the number of toes on the front feet have varied between four and five. The forehead is smoother and less convex than that of the Asian Elephant. The trunk is the most characteristic feature of the African Bush Elephant. It is formed by the fusion and elongation of the nose and upper lip, forming a flexible and strong organ made purely of muscle. Little scientific research has been carried out into elephants' cognitive or perceptual abilities. An exception is a recent report that African Bush Elephants are able to use seismic vibrations at infrasound frequencies for communication.
Woolly Mammoth - Mammuthus primigenius
The woolly mammoth (Mammuthus primigenius), also called the tundra mammoth, is a species of mammoth. This animal is known from bones and frozen carcasses from northern North America and northern Eurasia with the best preserved carcasses in Siberia. They are perhaps the most well known species of mammoth. This mammoth species was first recorded in (possibly 150,000 years old) deposits of the second last glaciation in Eurasia. It was derived from the steppe mammoth (Mammuthus armeniacus). It disappeared from most of its range at the end of the Pleistocene (10,000 years ago), with an isolated population still living on Wrangel Island until roughly 1700 BC. Woolly mammoths are common in the fossil record. Unlike most other prehistoric animals, their remains are often not literally fossilised - that is, turned into stone - but rather are preserved in their organic state. This is due in part to the frozen climate of their habitats, and to their massive size. Woolly mammoths are therefore among the best-understood prehistoric vertebrates known to science in terms of anatomy. Woolly mammoths lived in two groups which are speculated to be divergent enough to be characterised as subspecies. One group stayed in the middle of the high Arctic, while the other group had a much wider range. The Bering Land Bridge likely played an important role in structuring woolly mammoth populations, acting as an ecological barrier. Recent stable isotope studies of Siberian and New World mammoths has shown there were also differences in climatic conditions on either side of the Bering Land Bridge, with Siberia being more uniformly colder and drier throughout the Late Pleistocene. Woolly mammoths were not noticeably larger than present-day African elephants. Fully grown mammoth bulls reached heights between 2.8 m (9.2 ft) and 3.0 m (9.8 ft) while the dwarf varieties reached between 1.8 m (5.9 ft) and 2.3 m (7.5 ft). Woolly mammoths had a number of adaptations to the cold, most famously the thick layer of shaggy hair, up to 1 meter in length, with a fine underwool, for which the woolly mammoth is named. The coats were similar to those of muskoxen, and it is likely mammoths moulted in summer. They also had far smaller ears than modern elephants; the largest mammoth ear found so far was only 30 cm (12 in) long, compared to 180 cm (71 in) for an African elephant. Their skin was no thicker than that of present-day elephants, but unlike elephants, they had numerous sebaceous glands in their skin which secreted greasy fat into their hair, improving its insulating qualities. They had a layer of fat up to 8 cm (3.1 in) thick under the skin which, like the blubber of whales, helped to keep them warm. Similar to reindeer and musk oxen, their haemoglobin was adapted to the cold, with three genetic mutations to improve oxygen delivery around the body and prevent freezing. Other characteristic features included a high, peaked head that appears knob-like in many cave paintings, and a high shoulder hump resulting from long spinous processes on the neck vertebrae that probably carried fat deposits. Another feature at times found in cave paintings was confirmed by the discovery of the nearly intact remains of a baby mammoth named Dima. Unlike the trunk lobes of living elephants, Dima's upper lip at the tip of the trunk had a broad lobe feature, while the lower lip had a broad, squarish flap. Their teeth were also adapted to their diet of coarse tundra grasses, with more plates and a higher crown than their southern relatives. Woolly mammoths had extremely long tusks — up to 5 m (16 ft) long — which were markedly curved, to a much greater extent than those of elephants. It is not clear whether the tusks were a specific adaptation to their environment; mammoths may have used their tusks as shovels to clear snow from the ground and reach the vegetation buried below. This is evidenced by flat sections on the ventral surface of some tusks. It has also been observed in many specimens that there may be an amount of wear on top of the tusk that would suggest some animals had a preference as to which tusk on which they rested their trunks.
