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Hydrurga Leptonyx
The leopard seal (''Hydrurga leptonyx''), also referred to as the sea leopard, is the second largest species of seal in the Antarctic (after the southern elephant seal). Its only natural predator is the orca. It feeds on a wide range of prey including cephalopods, other pinnipeds, krill, fish, and birds, particularly penguins. It is the only species in the genus ''Hydrurga''. Its closest relatives are the Ross seal, the crabeater seal and the Weddell seal, which together are known as the tribe of Lobodontini seals. The name ''hydrurga'' means "water worker" and ''leptonyx'' is the Greek for "thin-clawed". Taxonomy French zoologist Henri Marie Ducrotay de Blainville described the leopard seal in 1820. Description The leopard seal has a distinctively long and muscular body shape when compared to other seals, but it is perhaps best known for its massive jaws, which allow it to be one of the top predators in its environment. The front teeth are sharp like those of other carnivore ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58See the 2014 version of the ICS geologic time scale million years ago. It is the second and most recent epoch of the Neogene Period in the . The Pliocene follows the Epoch and is followed by the Epoch. Prior to the 2009 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crabeater Seal
The crabeater seal (''Lobodon carcinophaga''), also known as the krill-eater seal, is a true seal with a circumpolar distribution around the coast of Antarctica. They are medium- to large-sized (over 2 m in length), relatively slender and pale-colored, found primarily on the free-floating pack ice that extends seasonally out from the Antarctic coast, which they use as a platform for resting, mating, social aggregation and accessing their prey. They are by far the most abundant seal species in the world. While population estimates are uncertain, there are at least 7 million and possibly as many as 75 million individuals. This success of this species is due to its specialized predation on the abundant Antarctic krill of the Southern Ocean, for which it has uniquely adapted, sieve-like tooth structure. Indeed, its scientific name, translated as "lobe-toothed (''lobodon'') crab eater (''carcinophaga'')", refers specifically to the finely lobed teeth adapted to filtering their small cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auricle (anatomy)
The auricle or auricula is the visible part of the ear that is outside the head. It is also called the pinna (Latin for "wing" or "fin", plural pinnae), a term that is used more in zoology. Structure The diagram shows the shape and location of most of these components: * ''antihelix'' forms a 'Y' shape where the upper parts are: ** ''Superior crus'' (to the left of the ''fossa triangularis'' in the diagram) ** ''Inferior crus'' (to the right of the ''fossa triangularis'' in the diagram) * ''Antitragus'' is below the ''tragus'' * ''Aperture'' is the entrance to the ear canal * ''Auricular sulcus'' is the depression behind the ear next to the head * ''Concha'' is the hollow next to the ear canal * Conchal angle is the angle that the back of the ''concha'' makes with the side of the head * ''Crus'' of the helix is just above the ''tragus'' * ''Cymba conchae'' is the narrowest end of the ''concha'' * External auditory meatus is the ear canal * ''Fossa triangularis'' is the depres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whiskers
Vibrissae (; singular: vibrissa; ), more generally called Whiskers, are a type of stiff, functional hair used by mammals to touch, sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are coarser as tactile sensors. Although whiskers are specifically those found around the face, vibrissae are known to grow in clusters at various places around the body. Most mammals have them, including all non-human primates and especially Nocturnality, nocturnal mammals. Whiskers are sensitive tactile hairs that aid navigation, locomotion, exploration, hunting, social touch and perform other functions. This article is primarily about the specialised sensing hairs of mammals, but some birds, fish, insects, crustaceans and other arthropods are known to have similar structures also used to sense the environment. Etymology Vibrissae (from Latin 'to vibrate') from the characteristic motion seen in a small rodent that is otherwise sitting sti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johns Hopkins University Press
The Johns Hopkins University Press (also referred to as JHU Press or JHUP) is the publishing division of Johns Hopkins University. It was founded in 1878 and is the oldest continuously running university press in the United States. The press publishes books and journals, and operates other divisions including fulfillment and electronic databases. Its headquarters are in Charles Village, Baltimore. In 2017, after the retirement of Kathleen Keane who is credited with modernizing JHU Press for the digital age, the university appointed new director Barbara Pope. Overview Daniel Coit Gilman, the first president of the Johns Hopkins University, inaugurated the press in 1878. The press began as the university's Publication Agency, publishing the ''American Journal of Mathematics'' in its first year and the ''American Chemical Journal'' in its second. It published its first book, ''Sidney Lanier: A Memorial Tribute'', in 1881 to honor the poet who was one of the university's first writers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walrus
The walrus (''Odobenus rosmarus'') is a large pinniped, flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in the family (biology), family Odobenidae and genus ''Odobenus''. This species is subdivided into two subspecies: the Atlantic walrus (''O. r. rosmarus''), which lives in the Atlantic Ocean, and the Pacific walrus (''O. r. divergens''), which lives in the Pacific Ocean. Adult walrus are characterised by prominent tusks and whiskers, and their considerable bulk: adult males in the Pacific can weigh more than and, among pinnipeds, are exceeded in size only by the two species of elephant seals. Walruses live mostly in shallow waters above the continental shelves, spending significant amounts of their lives on the sea ice looking for benthic zone, benthic bivalvia, bivalve mollusks to eat. Walruses are relatively long-lived, social animals, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leopard
The leopard (''Panthera pardus'') is one of the five extant species in the genus '' Panthera'', a member of the cat family, Felidae. It occurs in a wide range in sub-Saharan Africa, in some parts of Western and Central Asia, Southern Russia, and on the Indian subcontinent to Southeast and East Asia. It is listed as Vulnerable on the IUCN Red List because leopard populations are threatened by habitat loss and fragmentation, and are declining in large parts of the global range. The leopard is considered locally extinct in Hong Kong, Singapore, South Korea, Jordan, Morocco, Togo, the United Arab Emirates, Uzbekistan, Lebanon, Mauritania, Kuwait, Syria, Libya, Tunisia and most likely in North Korea, Gambia, Laos, Lesotho, Tajikistan, Vietnam and Israel. Contemporary records suggest that the leopard occurs in only 25% of its historical global range. Compared to other wild cats, the leopard has relatively short legs and a long body with a large skull. Its fur is marked with rosett ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Counter Shading
Countershading, or Thayer's law, is a method of camouflage in which an animal's coloration is darker on the top or upper side and lighter on the underside of the body. This pattern is found in many species of mammals, reptiles, birds, fish, and insects, both in predators and in prey. When light falls from above on a uniformly coloured three-dimensional object such as a sphere, it makes the upper side appear lighter and the underside darker, grading from one to the other. This pattern of light and shade makes the object appear solid, and therefore easier to detect. The classical form of countershading, discovered in 1909 by the artist Abbott Handerson Thayer, works by counterbalancing the effects of self-shadowing, again typically with grading from dark to light. In theory this could be useful for military camouflage, but in practice it has rarely been applied, despite the best efforts of Thayer and, later, in the Second World War, of the zoologist Hugh Cott. The precise functi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Krill
Antarctic krill (''Euphausia superba'') is a species of krill found in the Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 individual animals per cubic metre. It feeds directly on minute phytoplankton, thereby using the primary production energy that the phytoplankton originally derived from the sun in order to sustain their pelagic (open ocean) life cycle. It grows to a length of , weighs up to , and can live for up to six years. It is a key species in the Antarctic ecosystem and in terms of biomass, is one of the most abundant animal species on the planet (approximately 500 million tons, corresponding to 300 to 400 trillion individuals). Life cycle The main spawning season of Antarctic krill is from January to March, both above the continental shelf and also in the upper region of deep sea oceanic areas. In the typical way of all krill, the male attaches a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molar (tooth)
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone tooth", from ''mola'', millstone and ''dens'', tooth. Molars show a great deal of diversity in size and shape across mammal groups. The third molar of humans is sometimes vestigial. Human anatomy In humans, the molar teeth have either four or five cusps. Adult humans have 12 molars, in four groups of three at the back of the mouth. The third, rearmost molar in each group is called a wisdom tooth. It is the last tooth to appear, breaking through the front of the gum at about the age of 20, although this varies from individual to individual. Race can also affect the age at which this occurs, with statistical variations between groups. In some cases, it may not even erupt at all. The human mouth contains upper (maxillary) and lower (mandib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans Thewissen
Hans Thewissen is a Dutch-American paleontologist. His field work has discovered fossils for the steps in the transition from land to water in whales: '' Ambulocetus'', '' Pakicetus'', ''Indohyus'' and '' Kutchicetus''. He now studies modern bowhead and beluga whales in Alaska to learn about their biology and their implications for management and conservation. Early life Thewissen has always been interested in paleontology and natural history. His mother said that when Thewissen was a small boy, she had to sort through his pockets before laundry time to take out the rocks and worms he collected. His father used to take him to the town of Maastricht, and they collected fossils from the Maastrichtian period. 12th birthday present was a rock hammer, which has accompanied him on all collecting trips since. He grew up just 2 miles from Liessel, a fossil locale that yielded the first whales he ever collected. Educational background After finishing Gymnasium secondary education in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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