Post by DinosaurMichael on Jan 18, 2012 16:55:27 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.
Megatherium - Megatherium americanum
Megatherium ("Great Beast") was a genus of elephant-sized ground sloths endemic to Central America and South America that lived from the Pliocene through Pleistocene existing approximately 5.3 million years. Its size was exceeded by only a few other land mammals, including mammoths and the even larger Paraceratherium. The rhinoceros-sized Promegatherium is suggested to be the ancestor of Megatherium. Megatherium was one of the largest mammals known, weighing up to eight tons, about as much as an African bull elephant. Although it was primarily a quadruped, its footprints show that it was capable of assuming a bipedal stance. When it stood on its hind legs it was about twenty feet (6 m) tall, twice the height of an elephant. This sloth, like a modern anteater, walked on the sides of its feet because its claws prevented it from putting them flat on the ground. Megatherium species were members of the abundant Pleistocene megafauna, large mammals that lived during the Pleistocene epoch. Megatherium had a robust skeleton with a large pelvic girdle and a broad muscular tail. Its large size enabled it to feed at heights unreachable by other contemporary herbivores. Rising on its powerful hind legs and using its tail to form a tripod, Megatherium could support its massive body weight while using the curved claws on its long forelegs to pull down branches with the choicest leaves. Its jaw is believed to have housed a long tongue, which it would then use to pull leaves into its mouth, similar to the modern tree sloth. Some recent morpho-functional analysis indicates that M. americanum was adapted for strong vertical biting. The teeth are hypsodont and bilophodont, and the sagittal section of each loph is triangular with a sharp edge. This suggests the teeth were used for cutting, rather than grinding, and that hard fibrous food was not the primary dietary component. Megatherium americanum skeleton, Muséum national d'Histoire naturelle, ParisRichard Fariña and Ernesto Blanco of the Universidad de la República in Montevideo have analysed a fossil skeleton of M. americanum and discovered that its olecranon - the part of the elbow to which the triceps muscle attaches - was very short. This adaptation is found in carnivores and optimises speed rather than strength. The researchers say this would have enabled M. americanum to use its claws like daggers. They suggest that to add nutrients to its diet, Megatherium may have taken over the kills of Smilodon. Based on the estimated strength and mechanical advantage of its biceps, it has been proposed that Megatherium could have overturned adult glyptodonts (large, armored xenarthrans, related to armadillos) as a means of scavenging or hunting these animals. However, other zoologists have described this proposal as "fanciful".
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.
Megatherium - Megatherium americanum
Megatherium ("Great Beast") was a genus of elephant-sized ground sloths endemic to Central America and South America that lived from the Pliocene through Pleistocene existing approximately 5.3 million years. Its size was exceeded by only a few other land mammals, including mammoths and the even larger Paraceratherium. The rhinoceros-sized Promegatherium is suggested to be the ancestor of Megatherium. Megatherium was one of the largest mammals known, weighing up to eight tons, about as much as an African bull elephant. Although it was primarily a quadruped, its footprints show that it was capable of assuming a bipedal stance. When it stood on its hind legs it was about twenty feet (6 m) tall, twice the height of an elephant. This sloth, like a modern anteater, walked on the sides of its feet because its claws prevented it from putting them flat on the ground. Megatherium species were members of the abundant Pleistocene megafauna, large mammals that lived during the Pleistocene epoch. Megatherium had a robust skeleton with a large pelvic girdle and a broad muscular tail. Its large size enabled it to feed at heights unreachable by other contemporary herbivores. Rising on its powerful hind legs and using its tail to form a tripod, Megatherium could support its massive body weight while using the curved claws on its long forelegs to pull down branches with the choicest leaves. Its jaw is believed to have housed a long tongue, which it would then use to pull leaves into its mouth, similar to the modern tree sloth. Some recent morpho-functional analysis indicates that M. americanum was adapted for strong vertical biting. The teeth are hypsodont and bilophodont, and the sagittal section of each loph is triangular with a sharp edge. This suggests the teeth were used for cutting, rather than grinding, and that hard fibrous food was not the primary dietary component. Megatherium americanum skeleton, Muséum national d'Histoire naturelle, ParisRichard Fariña and Ernesto Blanco of the Universidad de la República in Montevideo have analysed a fossil skeleton of M. americanum and discovered that its olecranon - the part of the elbow to which the triceps muscle attaches - was very short. This adaptation is found in carnivores and optimises speed rather than strength. The researchers say this would have enabled M. americanum to use its claws like daggers. They suggest that to add nutrients to its diet, Megatherium may have taken over the kills of Smilodon. Based on the estimated strength and mechanical advantage of its biceps, it has been proposed that Megatherium could have overturned adult glyptodonts (large, armored xenarthrans, related to armadillos) as a means of scavenging or hunting these animals. However, other zoologists have described this proposal as "fanciful".
