Post by DinosaurMichael on Feb 24, 2012 14:36:37 GMT -5
American Bison - Bison bison
The American bison (Bison bison), also commonly known as the American buffalo, is a North American species of bison that once roamed the grasslands of North America in massive herds. Their range once roughly comprised a triangle between the Great Bear Lake in Canada's far northwest, south to the Mexican states of Durango and Nuevo León, and east along the western boundary of the Appalachian Mountains. Because of commercial hunting and slaughter in the 19th century, the bison nearly went extinct and is today restricted to a few national parks and other reserves. Two subspecies or ecotypes have been described: the plains bison (Bison bison bison), smaller in size and with a more rounded hump, and the wood bison (Bison bison athabascae) – the larger of the two and having a taller, square hump. Furthermore, it has been suggested that the plains bison consists of a northern (Bison bison montanae) and a southern subspecies, bringing the total to three. However, this is generally not supported. The wood bison is one of the largest species of bovid in the world, surpassed by only the Italian Chianina, the Asian gaur and wild Asian water buffalo. It is the largest extant land animal in North America. A bison has a shaggy, long, dark brown winter coat, and a lighter weight, lighter brown summer coat. As is typical in ungulates, the male bison are slightly larger than the female. Plains bison are often in the smaller range of sizes, and Wood bison in the larger range. Head-and-body length ranges from 2 to 3.5 m (6.6 to 11.5 ft) long, the tail adding 30 to 91 cm (12 to 36 in). Shoulder height in the species can range from 152 to 186 cm (60 to 73 in). Typical weigh can range from 318 to 1,000 kg (700 to 2,200 lb). The heaviest wild bull ever recorded weighed 1,270 kg (2,800 lb). When raised in captivity and farmed for meat, the bison can grow unnaturally heavy and the largest semi-domestic bison weighed 1,724 kg (3,800 lb). The heads and forequarters are massive, and both sexes have short, curved horns that can grow up to 2 feet (61 cm) long, which they use in fighting for status within the herd and for defense. Bison are herbivores, grazing on the grasses and sedges of the North American prairies. Their daily schedule involves two-hour periods of grazing, resting and cud chewing, then moving to a new location to graze again. Bison mate in August and September; gestation is 285 days. A single reddish-brown calf nurses until the next calf is born. If the cow is not pregnant, a calf will nurse for 18 months. Bison cows are mature enough to produce a calf at 3 years of age. Bison bulls may try to mate with cows at 3 years of age, but if more mature bulls are present, they may not be able to compete until they reach 5 years of age. Bison have a life expectancy of approximately 15 years in the wild and up to 25 years in captivity.
Ceratosaurus - Ceratosaurus nasicornis
Ceratosaurus ( /ˌsɛrətɵˈsɔrəs/) meaning "horned lizard", in reference to the horn on its nose (Greek κερας/κερατος, keras/keratos meaning "horn" and σαυρος/sauros meaning "lizard"), was a large predatory theropod dinosaur from the Late Jurassic Period (Kimmeridgian to Tithonian), found in the Morrison Formation of North America, in Tanzania and Portugal. It was characterized by large jaws with blade-like teeth, a large, blade-like horn on the snout and a pair of hornlets over the eyes. The forelimbs were powerfully built but very short. The bones of the sacrum were fused (synsacrum) and the pelvic bones were fused together and to this structure (Sereno 1997). A row of small osteoderms was present down the middle of the back. Ceratosaurus was a fairly typical theropod, with a large head, short forelimbs, robust hind legs, and a long tail. The skull of Ceratosaurus was quite large in proportion to the rest of its body. Each premaxilla contained only three teeth, and each maxilla (the main tooth-bearing bones in the upper jaw) held between twelve and fifteen flattened, exceptionally long teeth. Each dentary (the main tooth-bearing bone in the lower jaw) bore eleven to fifteen teeth. The prominent nose horn is formed from protuberances of the nasal bones. A juvenile specimen is known in which the two halves of the horn are not yet fused together. In addition to the large nasal horn, Ceratosaurus possessed smaller hornlike ridges in front of each eye, similar to those of Allosaurus. These ridges were formed by enlargement of the lacrimal bones. Uniquely among theropods, Ceratosaurus possessed dermal armor, in the form of small osteoderms running down the middle of its back. The tail of Ceratosaurus comprised about half of the body's total length. It was thin and flexible, with high vertebral spines. The type specimen was an individual about 17.5 feet (5.3 m) long; it is not clear whether this animal was fully grown. David B. Norman (1985) estimated that the maximum length of Ceratosaurus was 20 feet (6 m). A particularly large Ceratosaurus specimen from the Cleveland-Lloyd Quarry (UUVP 81), discovered in the mid-1960s, may have been up to 28.8 feet (8.8 m) long. Marsh (1884) suggested that Ceratosaurus weighed about half as much as Allosaurus. In Predatory Dinosaurs of the World, published in 1988, Gregory S. Paul estimated that the C. nasicornis holotype skeleton came from an animal weighing about 524 kilograms (1,160 lb). A large femur from the Cleveland-Lloyd Quarry represents a much bigger and heavier individual, whose bulk was estimated by Paul at about 980 kilograms (2,200 lb).
The American bison (Bison bison), also commonly known as the American buffalo, is a North American species of bison that once roamed the grasslands of North America in massive herds. Their range once roughly comprised a triangle between the Great Bear Lake in Canada's far northwest, south to the Mexican states of Durango and Nuevo León, and east along the western boundary of the Appalachian Mountains. Because of commercial hunting and slaughter in the 19th century, the bison nearly went extinct and is today restricted to a few national parks and other reserves. Two subspecies or ecotypes have been described: the plains bison (Bison bison bison), smaller in size and with a more rounded hump, and the wood bison (Bison bison athabascae) – the larger of the two and having a taller, square hump. Furthermore, it has been suggested that the plains bison consists of a northern (Bison bison montanae) and a southern subspecies, bringing the total to three. However, this is generally not supported. The wood bison is one of the largest species of bovid in the world, surpassed by only the Italian Chianina, the Asian gaur and wild Asian water buffalo. It is the largest extant land animal in North America. A bison has a shaggy, long, dark brown winter coat, and a lighter weight, lighter brown summer coat. As is typical in ungulates, the male bison are slightly larger than the female. Plains bison are often in the smaller range of sizes, and Wood bison in the larger range. Head-and-body length ranges from 2 to 3.5 m (6.6 to 11.5 ft) long, the tail adding 30 to 91 cm (12 to 36 in). Shoulder height in the species can range from 152 to 186 cm (60 to 73 in). Typical weigh can range from 318 to 1,000 kg (700 to 2,200 lb). The heaviest wild bull ever recorded weighed 1,270 kg (2,800 lb). When raised in captivity and farmed for meat, the bison can grow unnaturally heavy and the largest semi-domestic bison weighed 1,724 kg (3,800 lb). The heads and forequarters are massive, and both sexes have short, curved horns that can grow up to 2 feet (61 cm) long, which they use in fighting for status within the herd and for defense. Bison are herbivores, grazing on the grasses and sedges of the North American prairies. Their daily schedule involves two-hour periods of grazing, resting and cud chewing, then moving to a new location to graze again. Bison mate in August and September; gestation is 285 days. A single reddish-brown calf nurses until the next calf is born. If the cow is not pregnant, a calf will nurse for 18 months. Bison cows are mature enough to produce a calf at 3 years of age. Bison bulls may try to mate with cows at 3 years of age, but if more mature bulls are present, they may not be able to compete until they reach 5 years of age. Bison have a life expectancy of approximately 15 years in the wild and up to 25 years in captivity.
Ceratosaurus - Ceratosaurus nasicornis
Ceratosaurus ( /ˌsɛrətɵˈsɔrəs/) meaning "horned lizard", in reference to the horn on its nose (Greek κερας/κερατος, keras/keratos meaning "horn" and σαυρος/sauros meaning "lizard"), was a large predatory theropod dinosaur from the Late Jurassic Period (Kimmeridgian to Tithonian), found in the Morrison Formation of North America, in Tanzania and Portugal. It was characterized by large jaws with blade-like teeth, a large, blade-like horn on the snout and a pair of hornlets over the eyes. The forelimbs were powerfully built but very short. The bones of the sacrum were fused (synsacrum) and the pelvic bones were fused together and to this structure (Sereno 1997). A row of small osteoderms was present down the middle of the back. Ceratosaurus was a fairly typical theropod, with a large head, short forelimbs, robust hind legs, and a long tail. The skull of Ceratosaurus was quite large in proportion to the rest of its body. Each premaxilla contained only three teeth, and each maxilla (the main tooth-bearing bones in the upper jaw) held between twelve and fifteen flattened, exceptionally long teeth. Each dentary (the main tooth-bearing bone in the lower jaw) bore eleven to fifteen teeth. The prominent nose horn is formed from protuberances of the nasal bones. A juvenile specimen is known in which the two halves of the horn are not yet fused together. In addition to the large nasal horn, Ceratosaurus possessed smaller hornlike ridges in front of each eye, similar to those of Allosaurus. These ridges were formed by enlargement of the lacrimal bones. Uniquely among theropods, Ceratosaurus possessed dermal armor, in the form of small osteoderms running down the middle of its back. The tail of Ceratosaurus comprised about half of the body's total length. It was thin and flexible, with high vertebral spines. The type specimen was an individual about 17.5 feet (5.3 m) long; it is not clear whether this animal was fully grown. David B. Norman (1985) estimated that the maximum length of Ceratosaurus was 20 feet (6 m). A particularly large Ceratosaurus specimen from the Cleveland-Lloyd Quarry (UUVP 81), discovered in the mid-1960s, may have been up to 28.8 feet (8.8 m) long. Marsh (1884) suggested that Ceratosaurus weighed about half as much as Allosaurus. In Predatory Dinosaurs of the World, published in 1988, Gregory S. Paul estimated that the C. nasicornis holotype skeleton came from an animal weighing about 524 kilograms (1,160 lb). A large femur from the Cleveland-Lloyd Quarry represents a much bigger and heavier individual, whose bulk was estimated by Paul at about 980 kilograms (2,200 lb).
