Post by Deleted on Nov 16, 2013 0:12:23 GMT 5
Steller's Sea Lion - Eumetopias jubatus
The Steller sea lion (Eumetopias jubatus) also known as the northern sea lion and Steller's sea lion, is a near threatened species of sea lion in the northern Pacific. It is the sole member of the genus Eumetopias and the largest of the eared seals (Otariidae). Among pinnipeds, it is inferior in size only to the walrus and the two elephant seals. The species is named for the naturalist Georg Wilhelm Steller, who first described them in 1741. The Steller sea lion has attracted considerable attention in recent decades due to significant, unexplained declines in their numbers over a large portion of their range in Alaska. Adult animals are lighter in color than most sea lions, ranging from pale yellow to tawny and occasionally reddish. Steller sea lion pups are born almost black, weighing around 23 kg (51 lb), and remain dark for several months. Females and males both grow rapidly until the fifth year, after which female growth slows considerably. Adult females measure 2.3–2.9 m (7.5–9.5 ft) in length, with an average of 2.5 m (8.2 ft), and weigh 240–350 kg (530–770 lb), with an average of 263 kg (580 lb). Males continue to grow until their secondary sexual traits appear in their fifth to eighth year. Males are slightly longer than the females; they grow to about 2.82–3.25 m (9.3–10.7 ft) long, with an average of 3 m (9.8 ft). Males have much wider chests, necks and general forebody structure and weigh 450–1,120 kg (990–2,470 lb), with an average of 544 kg (1,199 lb). Males are further distinguished from females by broader, higher foreheads, flatter snouts, and darker, slightly tuftier hair around their large necks, giving them a maned appearance. Indeed, their Latin name translates roughly as: "maned one with the broad forehead". The range of the Steller sea lion extends from the Kuril Islands and the Sea of Okhotsk in Russia to the Gulf of Alaska in the north, and south to Año Nuevo Island off central California. They formerly bred as far south as the Channel Islands, but have not been observed there since the 1980s. Based on genetic an?lyses and local migration patterns, the global Steller sea lion population has traditionally been divided into an eastern and western stock at 144° W longitude, roughly through the middle of the Gulf of Alaska. Recent evidence suggests the sea lions in Russia in the Sea of Okhotsk and the Kuril Islands comprise a third Asian stock, while the sea lions on the eastern seaboard of Kamchatka and the Commander Islands belong to the western stock. In the summer, Steller sea lions tend to shift their range somewhat southward. Thus, though there are no reproductive rookeries in Japan, there are several consistent haulouts around Hokkaid? in the winter and spring. Vagrants have been spotted in the Yellow Sea and Bohai Gulf and along the coast of Korea and China. Steller sea lions are skilled and opportunistic marine predator feeding on a wide range of fish and cephalopod species. Important diet components include walleye pollock, Atka mackerel, halibut, herring, capelin, flatfish Pacific cod, rockfish, sculpins, and cephalopods. They seem to prefer schooling fish and remain primarily in between intertidal zones and continental shelves. They are also known to enter estuarine environments and feed on some semifreshwater fish such as sturgeon. Very occasionally, they have been known to prey on northern fur seals, harbor seals and sea otter pups. They are near the top of the marine food chain, but are susceptible to predation by killer whales and white sharks.
Tiger Shark - Galeocerdo cuvier
The tiger shark, Galeocerdo cuvier, is a species of requiem shark and the only member of the genus Galeocerdo. Commonly known as sea tiger, the tiger shark is a relatively large macropredator, capable of attaining a length of over 5 m (16 ft). It is found in many tropical and temperate waters, and is especially common around central Pacific islands. Its name derives from the dark stripes down its body which resemble a tiger's pattern, which fade as the shark matures. The tiger shark is a solitary, mostly night-time hunter. Its diet involves a wide range of prey, including crustaceans, fish, seals, birds, smaller sharks, squid, turtles, sea snakes, and dolphins. The tiger shark is considered a near threatened species due to finning and fishing by humans. While the tiger shark is considered to be one of the sharks most dangerous to humans, the attack rate is surprisingly low according to researchers. The tiger is second on the list of number of recorded attacks on humans, with the great white shark being first. They often visit shallow reefs, harbors and canals, creating the potential for encounter with humans. One of the largest sharks living today, the tiger shark commonly attains a length of 3 to 4.2 m (9.8 to 13.8 ft) and weighs around 385–635 kilograms (849–1,400 lb). Sometimes a male tiger shark can grow up to 4.5 meters (14-15 feet long) and females to 5.5 meters (18 feet long). A tiger shark can sometimes rival a great white shark in size. The tiger shark can grow up to 14-20 feet long. The skin of a tiger shark can typically range from blue to light green with a white or light yellow underbelly. Dark spots and stripes are most visible in young sharks and fade as the shark matures. Its head is somewhat wedge-shaped, which makes it easy to turn quickly to one side. They have small pits on the side of their upper bodies which hold electro-receptors called the ampullae of Lorenzini which enable them to detect electric fields, including the bio-electricity generated by prey. Tiger sharks also have a sensory organ called a lateral line which extends on their flanks down most of the length of their sides. The primary role of this structure is to detect minute vibrations in the water. These adaptations allow the tiger shark to hunt in darkness and detect hidden prey. A reflective layer behind the tiger shark's retina called the tapetum lucidum allows light-sensing cells a second chance to capture photons of visible light, enhancing vision in low light conditions. A tiger shark generally has long fins to provide lift as the shark maneuvers through water, while the long upper tail provides bursts of speed. Tiger sharks normally swim using small body movements. Its high back and dorsal fin act as a pivot, allowing it to spin quickly on its axis, though the shark's dorsal fins are distinctively close to its tail. Its teeth are specialized to slice through flesh, bone, and other tough substances such as turtle shells. Like most sharks, however, its teeth are continually replaced by rows of new teeth.
The Steller sea lion (Eumetopias jubatus) also known as the northern sea lion and Steller's sea lion, is a near threatened species of sea lion in the northern Pacific. It is the sole member of the genus Eumetopias and the largest of the eared seals (Otariidae). Among pinnipeds, it is inferior in size only to the walrus and the two elephant seals. The species is named for the naturalist Georg Wilhelm Steller, who first described them in 1741. The Steller sea lion has attracted considerable attention in recent decades due to significant, unexplained declines in their numbers over a large portion of their range in Alaska. Adult animals are lighter in color than most sea lions, ranging from pale yellow to tawny and occasionally reddish. Steller sea lion pups are born almost black, weighing around 23 kg (51 lb), and remain dark for several months. Females and males both grow rapidly until the fifth year, after which female growth slows considerably. Adult females measure 2.3–2.9 m (7.5–9.5 ft) in length, with an average of 2.5 m (8.2 ft), and weigh 240–350 kg (530–770 lb), with an average of 263 kg (580 lb). Males continue to grow until their secondary sexual traits appear in their fifth to eighth year. Males are slightly longer than the females; they grow to about 2.82–3.25 m (9.3–10.7 ft) long, with an average of 3 m (9.8 ft). Males have much wider chests, necks and general forebody structure and weigh 450–1,120 kg (990–2,470 lb), with an average of 544 kg (1,199 lb). Males are further distinguished from females by broader, higher foreheads, flatter snouts, and darker, slightly tuftier hair around their large necks, giving them a maned appearance. Indeed, their Latin name translates roughly as: "maned one with the broad forehead". The range of the Steller sea lion extends from the Kuril Islands and the Sea of Okhotsk in Russia to the Gulf of Alaska in the north, and south to Año Nuevo Island off central California. They formerly bred as far south as the Channel Islands, but have not been observed there since the 1980s. Based on genetic an?lyses and local migration patterns, the global Steller sea lion population has traditionally been divided into an eastern and western stock at 144° W longitude, roughly through the middle of the Gulf of Alaska. Recent evidence suggests the sea lions in Russia in the Sea of Okhotsk and the Kuril Islands comprise a third Asian stock, while the sea lions on the eastern seaboard of Kamchatka and the Commander Islands belong to the western stock. In the summer, Steller sea lions tend to shift their range somewhat southward. Thus, though there are no reproductive rookeries in Japan, there are several consistent haulouts around Hokkaid? in the winter and spring. Vagrants have been spotted in the Yellow Sea and Bohai Gulf and along the coast of Korea and China. Steller sea lions are skilled and opportunistic marine predator feeding on a wide range of fish and cephalopod species. Important diet components include walleye pollock, Atka mackerel, halibut, herring, capelin, flatfish Pacific cod, rockfish, sculpins, and cephalopods. They seem to prefer schooling fish and remain primarily in between intertidal zones and continental shelves. They are also known to enter estuarine environments and feed on some semifreshwater fish such as sturgeon. Very occasionally, they have been known to prey on northern fur seals, harbor seals and sea otter pups. They are near the top of the marine food chain, but are susceptible to predation by killer whales and white sharks.
Tiger Shark - Galeocerdo cuvier
The tiger shark, Galeocerdo cuvier, is a species of requiem shark and the only member of the genus Galeocerdo. Commonly known as sea tiger, the tiger shark is a relatively large macropredator, capable of attaining a length of over 5 m (16 ft). It is found in many tropical and temperate waters, and is especially common around central Pacific islands. Its name derives from the dark stripes down its body which resemble a tiger's pattern, which fade as the shark matures. The tiger shark is a solitary, mostly night-time hunter. Its diet involves a wide range of prey, including crustaceans, fish, seals, birds, smaller sharks, squid, turtles, sea snakes, and dolphins. The tiger shark is considered a near threatened species due to finning and fishing by humans. While the tiger shark is considered to be one of the sharks most dangerous to humans, the attack rate is surprisingly low according to researchers. The tiger is second on the list of number of recorded attacks on humans, with the great white shark being first. They often visit shallow reefs, harbors and canals, creating the potential for encounter with humans. One of the largest sharks living today, the tiger shark commonly attains a length of 3 to 4.2 m (9.8 to 13.8 ft) and weighs around 385–635 kilograms (849–1,400 lb). Sometimes a male tiger shark can grow up to 4.5 meters (14-15 feet long) and females to 5.5 meters (18 feet long). A tiger shark can sometimes rival a great white shark in size. The tiger shark can grow up to 14-20 feet long. The skin of a tiger shark can typically range from blue to light green with a white or light yellow underbelly. Dark spots and stripes are most visible in young sharks and fade as the shark matures. Its head is somewhat wedge-shaped, which makes it easy to turn quickly to one side. They have small pits on the side of their upper bodies which hold electro-receptors called the ampullae of Lorenzini which enable them to detect electric fields, including the bio-electricity generated by prey. Tiger sharks also have a sensory organ called a lateral line which extends on their flanks down most of the length of their sides. The primary role of this structure is to detect minute vibrations in the water. These adaptations allow the tiger shark to hunt in darkness and detect hidden prey. A reflective layer behind the tiger shark's retina called the tapetum lucidum allows light-sensing cells a second chance to capture photons of visible light, enhancing vision in low light conditions. A tiger shark generally has long fins to provide lift as the shark maneuvers through water, while the long upper tail provides bursts of speed. Tiger sharks normally swim using small body movements. Its high back and dorsal fin act as a pivot, allowing it to spin quickly on its axis, though the shark's dorsal fins are distinctively close to its tail. Its teeth are specialized to slice through flesh, bone, and other tough substances such as turtle shells. Like most sharks, however, its teeth are continually replaced by rows of new teeth.
