Post by DinosaurMichael on Jul 12, 2012 15:45:59 GMT -5
Jaguar - Panthera onca
The jaguar ( /ˈdʒæɡwɑr/ or UK /ˈdʒæɡjuː.ər/; Panthera onca) is a big cat, a feline in the Panthera genus, and is the only Panthera species found in the Americas. The jaguar is the third-largest feline after the tiger and the lion, and the largest in the Western Hemisphere. The jaguar's present range extends from Southern United States and Mexico across much of Central America and south to Paraguay and northern Argentina. Apart from a known and possibly breeding population in Arizona (southeast of Tucson), the cat has largely been extirpated from the United States since the early 20th century. This spotted cat most closely resembles the leopard physically, although it is usually larger and of sturdier build and its behavioural and habitat characteristics are closer to those of the tiger. While dense rainforest is its preferred habitat, the jaguar will range across a variety of forested and open terrain. It is strongly associated with the presence of water and is notable, along with the tiger, as a feline that enjoys swimming. The jaguar is largely a solitary, opportunistic, stalk-and-ambush predator at the top of the food chain (an apex predator). It is a keystone species, playing an important role in stabilizing ecosystems and regulating the populations of the animals it hunts. The jaguar has an exceptionally powerful bite, even relative to the other big cats. This allows it to pierce the shells of armoured reptiles and to employ an unusual killing method: it bites directly through the skull of prey between the ears to deliver a fatal bite to the brain. The jaguar is a compact and well-muscled animal. There are significant variations in size and weight: weights are normally in the range of 56–96 kilograms (124–211 lb). Larger males have been recorded at as much as 160 kg (350 lb) (roughly matching a tigress or lioness), and the smallest females have low weights of 36 kg (79 lb). Females are typically 10–20% smaller than males. The length of the cat varies from 1.2 to 1.95 m (3.9 to 6.4 ft), and its tail may add a further 45 to 75 cm (18 to 30 in). It stands about 63 to 76 cm (25 to 30 in) tall at the shoulders. Like the slightly smaller Old World leopard, this cat is relatively short and stocky in build. Further variations in size have been observed across regions and habitats, with size tending to increase from the north to south. A study of the jaguar in the Chamela-Cuixmala Biosphere Reserve on the Mexican Pacific coast, showed ranges of just about 50 kilograms (110 lb), about the size of the cougar. By contrast, a study of the Jaguar in the Brazilian Pantanal region found average weights of 100 kilograms (220 lb) and weights of 136 kilograms (300 lb) or more are not uncommon in old males. Forest jaguars are frequently darker and considerably smaller than those found in open areas (the Pantanal is an open wetland basin), possibly due to the smaller numbers of large herbivorous prey in forest areas. A short and stocky limb structure makes the jaguar adept at climbing, crawling and swimming. The head is robust and the jaw extremely powerful. The jaguar has the strongest bite of all felids, capable of biting down with 2,000 pounds-force (8,900 N). This is twice the strength of a lion and the second strongest of all mammals after the spotted hyena; this strength is an adaptation that allows the jaguar to pierce turtle shells. A comparative study of bite force adjusted for body size ranked it as the top felid, alongside the clouded leopard and ahead of the lion and tiger. It has been reported that "an individual jaguar can drag a 360 kg (800 lb) bull 8 m (25 ft) in its jaws and pulverize the heaviest bones". The jaguar hunts wild animals weighing up to 300 kilograms (660 lb) in dense jungle, and its short and sturdy physique is thus an adaptation to its prey and environment. The base coat of the jaguar is generally a tawny yellow, but can range to reddish-brown and black. The cat is covered in rosettes for camouflage in its jungle habitat. The spots vary over individual coats and between individual Jaguars: rosettes may include one or several dots, and the shape of the dots varies. The spots on the head and neck are generally solid, as are those on the tail, where they may merge to form a band. The underbelly, throat and outer surface of the legs and lower flanks are white. While the jaguar closely resembles the leopard, it is sturdier and heavier, and the two animals can be distinguished by their rosettes: the rosettes on a jaguar's coat are larger, fewer in number, usually darker, and have thicker lines and small spots in the middle that the leopard lacks. Jaguars also have rounder heads and shorter, stockier limbs compared to leopards.
Deinonychus - Deinonychus antirrhopus
Deinonychus ( /daɪˈnɒnɨkəs/ dy-non-i-kəs; Greek: äåéíüò, 'terrible' and ὄíõî, genitive ὄíõ÷ïò 'claw') was a genus of carnivorous dromaeosaurid dinosaur. There is one described species, Deinonychus antirrhopus. This 3.4 meter (11 ft) long dinosaur lived during the early Cretaceous Period, about 115–108 million years ago (from the mid-Aptian to early Albian stages). Fossils have been recovered from the U.S. states of Montana, Wyoming, and Oklahoma, in rocks of the Cloverly Formation and Antlers Formation, though teeth that may belong to Deinonychus have been found much farther east in Maryland. Paleontologist John Ostrom's study of Deinonychus in the late 1960s revolutionized the way scientists thought about dinosaurs, leading to the "dinosaur renaissance" and igniting the debate on whether dinosaurs were warm-blooded or cold blooded. Before this, the popular conception of dinosaurs had been one of plodding, reptilian giants. Ostrom noted the small body, sleek, horizontal posture, ratite-like spine, and especially the enlarged raptorial claws on the feet, which suggested an active, agile predator. "Terrible claw" refers to the unusually large, sickle-shaped talon on the second toe of each hind foot. The fossil YPM 5205 preserves a large, strongly curved ungual. In life, archosaurs have a horny sheath over this bone which extends the length. Ostrom looked at crocodile and bird claws and reconstructed the claw for YPM 5205 as over 120 millimetres (4.7 in) long. The species name antirrhopus means “counter balance”, which refers to Ostrom's idea about the function of the tail. As in other dromaeosaurids, the tail vertebrae have a series of ossified tendons and super-elongated bone processes. These features seemed to make the tail into a stiff counterbalance, but a fossil of the very closely related Velociraptor mongoliensis (IGM 100/986) has an articulated tail skeleton that is curved laterally in a long S–shape. This suggests that, in life, the tail could bend to the sides with a high degree of flexibility. Based on the largest known specimens, Deinonychus could reach at least 3.4 metres (11 ft 2 in) in length, with a skull length of 410 mm (16.1 in), a hip height of 0.87 metres (2 ft 10 in), and an estimated weight of 73 kilograms (160 lb). Its skull was equipped with powerful jaws lined with around seventy curved, blade-like teeth. Studies of the skull have progressed a great deal over the decades. Ostrom reconstructed the partial, imperfectly preserved, skulls that he had as triangular, broad, and fairly similar to Allosaurus. Additional Deinonychus skull material and closely related species found with good three-dimensional preservation show that the palate was more vaulted than Ostrom thought, making the snout far narrower, while the jugals flared broadly, giving greater stereoscopic vision. The skull of Deinonychus was different from that of Velociraptor, however, in that it had a more robust skull roof like that of Dromaeosaurus, and did not have the depressed nasals of Velociraptor. Both the skull and the lower jaw had fenestrae (skull openings) which reduced the weight of the skull. In Deinonychus, the antorbital fenestra, a skull opening between the eye and nostril, was particularly large. Deinonychus possessed large hands (manus) with three claws on each forelimb. The first digit was shortest and the second was longest. Each hind foot bore a sickle-shaped claw on the second digit, which was probably used during predation.
The jaguar ( /ˈdʒæɡwɑr/ or UK /ˈdʒæɡjuː.ər/; Panthera onca) is a big cat, a feline in the Panthera genus, and is the only Panthera species found in the Americas. The jaguar is the third-largest feline after the tiger and the lion, and the largest in the Western Hemisphere. The jaguar's present range extends from Southern United States and Mexico across much of Central America and south to Paraguay and northern Argentina. Apart from a known and possibly breeding population in Arizona (southeast of Tucson), the cat has largely been extirpated from the United States since the early 20th century. This spotted cat most closely resembles the leopard physically, although it is usually larger and of sturdier build and its behavioural and habitat characteristics are closer to those of the tiger. While dense rainforest is its preferred habitat, the jaguar will range across a variety of forested and open terrain. It is strongly associated with the presence of water and is notable, along with the tiger, as a feline that enjoys swimming. The jaguar is largely a solitary, opportunistic, stalk-and-ambush predator at the top of the food chain (an apex predator). It is a keystone species, playing an important role in stabilizing ecosystems and regulating the populations of the animals it hunts. The jaguar has an exceptionally powerful bite, even relative to the other big cats. This allows it to pierce the shells of armoured reptiles and to employ an unusual killing method: it bites directly through the skull of prey between the ears to deliver a fatal bite to the brain. The jaguar is a compact and well-muscled animal. There are significant variations in size and weight: weights are normally in the range of 56–96 kilograms (124–211 lb). Larger males have been recorded at as much as 160 kg (350 lb) (roughly matching a tigress or lioness), and the smallest females have low weights of 36 kg (79 lb). Females are typically 10–20% smaller than males. The length of the cat varies from 1.2 to 1.95 m (3.9 to 6.4 ft), and its tail may add a further 45 to 75 cm (18 to 30 in). It stands about 63 to 76 cm (25 to 30 in) tall at the shoulders. Like the slightly smaller Old World leopard, this cat is relatively short and stocky in build. Further variations in size have been observed across regions and habitats, with size tending to increase from the north to south. A study of the jaguar in the Chamela-Cuixmala Biosphere Reserve on the Mexican Pacific coast, showed ranges of just about 50 kilograms (110 lb), about the size of the cougar. By contrast, a study of the Jaguar in the Brazilian Pantanal region found average weights of 100 kilograms (220 lb) and weights of 136 kilograms (300 lb) or more are not uncommon in old males. Forest jaguars are frequently darker and considerably smaller than those found in open areas (the Pantanal is an open wetland basin), possibly due to the smaller numbers of large herbivorous prey in forest areas. A short and stocky limb structure makes the jaguar adept at climbing, crawling and swimming. The head is robust and the jaw extremely powerful. The jaguar has the strongest bite of all felids, capable of biting down with 2,000 pounds-force (8,900 N). This is twice the strength of a lion and the second strongest of all mammals after the spotted hyena; this strength is an adaptation that allows the jaguar to pierce turtle shells. A comparative study of bite force adjusted for body size ranked it as the top felid, alongside the clouded leopard and ahead of the lion and tiger. It has been reported that "an individual jaguar can drag a 360 kg (800 lb) bull 8 m (25 ft) in its jaws and pulverize the heaviest bones". The jaguar hunts wild animals weighing up to 300 kilograms (660 lb) in dense jungle, and its short and sturdy physique is thus an adaptation to its prey and environment. The base coat of the jaguar is generally a tawny yellow, but can range to reddish-brown and black. The cat is covered in rosettes for camouflage in its jungle habitat. The spots vary over individual coats and between individual Jaguars: rosettes may include one or several dots, and the shape of the dots varies. The spots on the head and neck are generally solid, as are those on the tail, where they may merge to form a band. The underbelly, throat and outer surface of the legs and lower flanks are white. While the jaguar closely resembles the leopard, it is sturdier and heavier, and the two animals can be distinguished by their rosettes: the rosettes on a jaguar's coat are larger, fewer in number, usually darker, and have thicker lines and small spots in the middle that the leopard lacks. Jaguars also have rounder heads and shorter, stockier limbs compared to leopards.
Deinonychus - Deinonychus antirrhopus
Deinonychus ( /daɪˈnɒnɨkəs/ dy-non-i-kəs; Greek: äåéíüò, 'terrible' and ὄíõî, genitive ὄíõ÷ïò 'claw') was a genus of carnivorous dromaeosaurid dinosaur. There is one described species, Deinonychus antirrhopus. This 3.4 meter (11 ft) long dinosaur lived during the early Cretaceous Period, about 115–108 million years ago (from the mid-Aptian to early Albian stages). Fossils have been recovered from the U.S. states of Montana, Wyoming, and Oklahoma, in rocks of the Cloverly Formation and Antlers Formation, though teeth that may belong to Deinonychus have been found much farther east in Maryland. Paleontologist John Ostrom's study of Deinonychus in the late 1960s revolutionized the way scientists thought about dinosaurs, leading to the "dinosaur renaissance" and igniting the debate on whether dinosaurs were warm-blooded or cold blooded. Before this, the popular conception of dinosaurs had been one of plodding, reptilian giants. Ostrom noted the small body, sleek, horizontal posture, ratite-like spine, and especially the enlarged raptorial claws on the feet, which suggested an active, agile predator. "Terrible claw" refers to the unusually large, sickle-shaped talon on the second toe of each hind foot. The fossil YPM 5205 preserves a large, strongly curved ungual. In life, archosaurs have a horny sheath over this bone which extends the length. Ostrom looked at crocodile and bird claws and reconstructed the claw for YPM 5205 as over 120 millimetres (4.7 in) long. The species name antirrhopus means “counter balance”, which refers to Ostrom's idea about the function of the tail. As in other dromaeosaurids, the tail vertebrae have a series of ossified tendons and super-elongated bone processes. These features seemed to make the tail into a stiff counterbalance, but a fossil of the very closely related Velociraptor mongoliensis (IGM 100/986) has an articulated tail skeleton that is curved laterally in a long S–shape. This suggests that, in life, the tail could bend to the sides with a high degree of flexibility. Based on the largest known specimens, Deinonychus could reach at least 3.4 metres (11 ft 2 in) in length, with a skull length of 410 mm (16.1 in), a hip height of 0.87 metres (2 ft 10 in), and an estimated weight of 73 kilograms (160 lb). Its skull was equipped with powerful jaws lined with around seventy curved, blade-like teeth. Studies of the skull have progressed a great deal over the decades. Ostrom reconstructed the partial, imperfectly preserved, skulls that he had as triangular, broad, and fairly similar to Allosaurus. Additional Deinonychus skull material and closely related species found with good three-dimensional preservation show that the palate was more vaulted than Ostrom thought, making the snout far narrower, while the jugals flared broadly, giving greater stereoscopic vision. The skull of Deinonychus was different from that of Velociraptor, however, in that it had a more robust skull roof like that of Dromaeosaurus, and did not have the depressed nasals of Velociraptor. Both the skull and the lower jaw had fenestrae (skull openings) which reduced the weight of the skull. In Deinonychus, the antorbital fenestra, a skull opening between the eye and nostril, was particularly large. Deinonychus possessed large hands (manus) with three claws on each forelimb. The first digit was shortest and the second was longest. Each hind foot bore a sickle-shaped claw on the second digit, which was probably used during predation.
