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Pteronotus Personatus
Wagner's mustached bat (''Pteronotus personatus'') is a bat species from South and Central America. It is one of the few New World bats species known to perform Doppler shift compensation behavior. Description Wagner's mustached bat is a relatively small bat, with a head-body length of and a tail long. There are two color phases, with some individuals having blackish-brown fur over the back and head with drab grey underparts, and others being clay-brown to reddish yellow with buff or cinnamon underparts. Individuals of both color phases can be found together in the same cave. The ears are long and pointed, with sharp serrations along the medial edges and a spatulate tragus including a shelf-like fold. The upper lip has a number of heavy bristles and surrounds the nose, with numerous folds and small projections along its edge. The snout is raised upwards, while the remainder of the skull is relatively flattened. The incisor teeth are reduced in size, but have a complex shape w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Andreas Wagner
Johann Andreas Wagner (21 March 1797 – 17 December 1861) was a German palaeontologist, zoologist and archaeologist who wrote several important works on palaeontology. Career Wagner was a professor at the University of Munich, and curator of the Zoologische Staatssammlung (State Zoology Collection). He was the author of ''Die Geographische Verbreitung der Säugethiere Dargestellt'' (1844–46). Wagner was a Christian creationist. Pikermi In his travels to the fossil beds of Pikermi, Wagner discovered and described fossil remains of mastodon, '' Dinotherium'', ''Hipparion ''Hipparion'' (Greek, "pony") is an extinct genus of horse that lived in North America, Asia, Europe, and Africa during the Miocene through Pleistocene ~23 Mya—781,000 years ago. It lived in non-forested, grassy plains, shortgrass prairie or ...'', two species of giraffe, antelope and others. His collaboration with Johannes Roth on these fossils became a major textbook in palaeontology, known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area and the seventh most populous. Its capital is Brasília, and its most populous city is São Paulo. The federation is composed of the union of the 26 States of Brazil, states and the Federal District (Brazil), Federal District. It is the largest country to have Portuguese language, Portuguese as an List of territorial entities where Portuguese is an official language, official language and the only one in the Americas; one of the most Multiculturalism, multicultural and ethnically diverse nations, due to over a century of mass Immigration to Brazil, immigration from around the world; and the most populous Catholic Church by country, Roman Catholic-majority country. Bounded by the Atlantic Ocean on the east, Brazil has a Coastline of Brazi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doppler Shift Compensation
When an echolocating bat approaches a target, its outgoing sounds return as echoes, which are Doppler shifted upward in frequency. In certain species of bats, which produce constant frequency (CF) echolocation calls, the bats compensate for the Doppler shift by changing their call frequency as they change speed towards a target. This keeps the returning echo in the same frequency range of the normal echolocation call. This dynamic frequency modulation is called the Doppler shift compensation (DSC), and was discovered by Hans Schnitzler in 1968. CF bats employ the DSC mechanism to maintain the echo frequency within a narrow frequency range.Hiryu, S. Shiori, Y. Hosokawa, T. Riquimaroux, H. Wantanabe, Y. 2008. On Board Telemetry of Emitted Sounds from free-flying bats: Compensation for velocity and distance stabilize echo frequency. Journal of Comparative Physiology A. 194: 841–851. This narrow frequency range is referred to as the acoustic fovea. By modulating the frequency o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrasound
Ultrasound is sound waves with frequency, frequencies higher than the upper audible limit of human hearing range, hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies from person to person and is approximately 20 Hertz, kilohertz (20,000 hertz) in healthy young adults. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz. Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws. Industrially, ultrasound is used for cleaning, mixing, and accelerating chemical processes. Animals such as bats and porpoises use ultrasound for locating Predation, prey and obstacles. History Acoustics, the science of sound, starts as far back as Pyth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Echolocation
Echolocation, also called bio sonar, is a biological sonar used by several animal species. Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects. Echolocation is used for navigation, foraging, and hunting in various environments. Echolocating animals include some mammals (most notably Laurasiatheria) and a few birds, especially some bat species and odontocetes (toothed whales and dolphins), but also in simpler forms in other groups such as shrews, and two cave-dwelling bird groups, the so-called cave swiftlets in the genus ''Aerodramus'' (formerly ''Collocalia'') and the unrelated oilbird ''Steatornis caripensis''. Early research The term ''echolocation'' was coined in 1938 by the American zoologist Donald Griffin, who, with Robert Galambos, first demonstrated the phenomenon in bats. As Griffin described in his book, the 18th century I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypothermia
Hypothermia is defined as a body core temperature below in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe hypothermia, there may be hallucinations and paradoxical undressing, in which a person removes their clothing, as well as an increased risk of the heart stopping. Hypothermia has two main types of causes. It classically occurs from exposure to cold weather and cold water immersion. It may also occur from any condition that decreases heat production or increases heat loss. Commonly, this includes alcohol intoxication but may also include low blood sugar, anorexia and advanced age. Body temperature is usually maintained near a constant level of through thermoregulation. Efforts to increase body temperature involve shivering, increased voluntary activity, and putting on warmer clothing. Hypothermia may be diagnosed based on either a person ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chilonycteris
''Pteronotus'' is a genus of bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most bi ...s. Eight extant species have been recognized, as well as one relatively recently extinct species. References * Gutierrez, E.E. & Molinari, J. 2008. Morphometrics and taxonomy of bats of the genus ''Pteronotus'' (subgenus ''Phyllodia'') in Venezuela. Journal of Mammalogy 89(2): 292–305. Bat genera Taxa named by John Edward Gray {{bat-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups of organisms. These relationships are determined by Computational phylogenetics, phylogenetic inference methods that focus on observed heritable traits, such as DNA sequences, protein amino acid sequences, or morphology. The result of such an analysis is a phylogenetic tree—a diagram containing a hypothesis of relationships that reflects the evolutionary history of a group of organisms. The tips of a phylogenetic tree can be living taxa or fossils, and represent the "end" or the present time in an evolutionary lineage. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the tree. An unrooted tree diagram (a network) makes no assumption about the ancestral line, and does ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek grc, label=none, πλεῖστος, pleīstos, most and grc, label=none, καινός, kainós (latinized as ), 'new'. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by the Isthmus of Panama, causing Great American Interchang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tobago
Tobago () is an List of islands of Trinidad and Tobago, island and Regions and municipalities of Trinidad and Tobago, ward within the Trinidad and Tobago, Republic of Trinidad and Tobago. It is located northeast of the larger island of Trinidad and about off the northeastern coast of Venezuela. It also lies to the southeast of Grenada. The official bird of Tobago is the cocrico. Etymology Tobago was named ''Belaforme'' by Christopher Columbus "because from a distance it seemed beautiful". The Spanish friar Antonio Vázquez de Espinosa wrote that the Kalina people, Kalina (mainland Caribs) called the island ''Urupina'' because of its resemblance to a big snail, while the Island Caribs, Kalinago (Island Caribs) called it ''Aloubaéra'', supposedly because it resembled the ''alloüebéra'', a giant snake which was supposed to live in a cave on the island of Dominica. The earliest known record of the use of the name ''Tabaco'' to refer to the island is a Spanish royal order is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canyon
A canyon (from ; archaic British English spelling: ''cañon''), or gorge, is a deep cleft between escarpments or cliffs resulting from weathering and the erosion, erosive activity of a river over geologic time scales. Rivers have a natural tendency to cut through underlying surfaces, eventually wearing away rock layers as sediments are removed downstream. A river bed will gradually reach a baseline elevation, which is the same elevation as the body of water into which the river drains. The processes of weathering and erosion will form canyons when the river's River source, headwaters and estuary are at significantly different elevations, particularly through regions where softer rock layers are intermingled with harder layers more resistant to weathering. A canyon may also refer to a rift between two mountain peaks, such as those in ranges including the Rocky Mountains, the Alps, the Himalayas or the Andes. Usually, a river or stream carves out such splits between mountains. Examp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arroyo (creek)
An arroyo (; from Spanish arroyo , "brook"), also called a wash, is a dry stream, creek, stream bed or gulch that temporarily or seasonally fills and flows after sufficient rain. Flash floods are common in arroyos following thunderstorms. ''Wadi'' (Arabic) is used in North Africa and Western Asia for similar landforms. The desert dry wash biome is restricted to the arroyos of the southwestern United States. Arroyos provide a water source to desert animals. Types and processes Arroyos can be natural fluvial landforms or constructed flood control channels. The term usually applies to a Grade (slope), sloped or mountainous terrain in xeric and desert climates. In addition: in many rural communities arroyos are also the principal transportation routes; and in many urban communities arroyos are also parks and recreational locations, often with linear multi-use bicycle, pedestrian, and equestrian trails. Flash flooding can cause the deep arroyos or deposition of sediment on flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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