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Spermophilus Beecheyi
The California ground squirrel (''Otospermophilus beecheyi''), also known as the Beechey ground squirrel, is a common and easily observed ground squirrel of the western United States and the Baja California Peninsula; it is common in Oregon and California and its range has relatively recently extended into Washington and northwestern Nevada. Formerly placed in ''Spermophilus'', as ''Spermophilus beecheyi'', it was reclassified in '' Otospermophilus'' in 2009, as it became clear that ''Spermophilus'' as previously defined was not a natural ( monophyletic) group. A full species account was published for this species in 2016. Etymology John Richardson, who originally described the species as ''Arctomys (Spermophilus) beecheyi'', or "Beechey's marmot", named it after Frederick William Beechey, an early 19th-century British explorer and naval officer. Description The squirrel's upper parts are mottled, with the fur containing a mixture of gray, light brown and dusky hairs. The sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Richardson (naturalist)
Sir John Richardson Royal Society of London, FRS FRSE (5 November 1787 – 5 June 1865) was a Scotland, Scottish naval surgeon, natural history, naturalist and Arctic explorer. Life Richardson was born at Nith Place in Dumfries the son of Gabriel Richardson, Provost of Dumfries, and his wife, Anne Mundell. He was educated at Dumfries Grammar School. He was then apprenticed to his maternal uncle, Dr James Mundell, a surgeon in Dumfries. He studied medicine at Edinburgh University, and became a surgeon in the navy in 1807. He traveled with John Franklin in search of the Northwest Passage on the Coppermine Expedition of 1819–1822. Richardson wrote the sections on geology, botany and ichthyology for the official account of the expedition. Franklin and Richardson returned to Canada in 1825 and went overland by fur trade routes to the mouth of the Mackenzie River. Franklin was to go as far west as possible and Richardson was to go east to the mouth of the Coppermine River. These ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estivation
Aestivation ( la, aestas (summer); also spelled estivation in American English) is a state of animal dormancy, similar to hibernation, although taking place in the summer rather than the winter. Aestivation is characterized by inactivity and a lowered metabolic rate, that is entered in response to high temperatures and arid conditions. It takes place during times of heat and dryness, the hot dry season, which are often the summer months. Invertebrate and vertebrate animals are known to enter this state to avoid damage from high temperatures and the risk of desiccation. Both terrestrial and aquatic animals undergo aestivation. Fossil records suggest that aestivation may have evolved several hundred million years ago. Physiology Organisms that aestivate appear to be in a fairly "light" state of dormancy, as their physiological state can be rapidly reversed, and the organism can quickly return to a normal state. A study done on '' Otala lactea'', a snail native to parts of Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals Of The United States
About 490 species of mammals are recorded in the United States. Unincorporated territories like for example Puerto Rico, Guam or Northern Mariana Islands are not covered. Mammals introduced and extinct in the Holocene except Pleistocene/Holocene boundary are included. According to the IUCN Red List 3 of these species are critically endangered, 20 endangered, 15 vulnerable, 20 near threatened and 4 extinct. Some species are identified as indicated below: *(A) - Accidental *(E) - Extinct *(Ex) - Extirpated (extinct in the US, but exists elsewhere in the world) *(I) - Introduced The following tags are used to highlight each species' conservation status as assessed by the International Union for Conservation of Nature: (v. 2013.2, the data are current as of March 5, 2014) and the Endangered Species Act: (the data are current as of March 28, 2014) Subclass: Theria Infraclass: Metatheria Order: Didelphimorphia (common opossums) ---- Didelphimorphia is the order of common ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals Of Mexico
This is a list of the native wild mammal species recorded in Mexico. As of September 2014, there were 536 mammalian species or subspecies listed. Based on International Union for Conservation of Nature, IUCN data, Mexico has 23% more noncetacean mammal species than the U.S. and Canada combined in an area only 10% as large, or a species density over 12 times that of its northern neighbors. Mexico's high mammal biodiversity is in part a reflection of the wide array of biomes present over its latitudinal, climatic and altitudinal ranges, from lowland tropical rainforest to temperate desert to montane forest to alpine tundra. The general increase in terrestrial biodiversity moving towards the equator is another important factor in the comparison. Mexico includes much of the Mesoamerica#Biodiversity, Mesoamerican and Madrean pine-oak woodlands biodiversity hotspots. From a biogeographic standpoint, most of Mexico is linked to the rest of North America as part of the Nearctic realm. Howeve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodents Of North America
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are native to all major land masses except for New Zealand, Antarctica, and several oceanic islands, though they have subsequently been introduced to most of these land masses by human activity. Rodents are extremely diverse in their ecology and lifestyles and can be found in almost every terrestrial habitat, including human-made environments. Species can be arboreal, fossorial (burrowing), saltatorial/richochetal (leaping on their hind legs), or semiaquatic. However, all rodents share several morphological features, including having only a single upper and lower pair of ever-growing incisors. Well-known rodents include mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, and hamsters. Rabbits, hares, and pikas, whose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around 1 millimeter (300 GHz) to the nominal red edge of the visible spectrum, around 700 nanometers (430 THz). Longer IR wavelengths (30 μm-100 μm) are sometimes included as part of the terahertz radiation range. Almost all black-body radiation from objects near room temperature is at infrared wavelengths. As a form of electromagnetic radiation, IR propagates energy and momentum, exerts radiation pressure, and has properties corresponding to both those of a wave and of a particle, the photon. It was long known that fires emit invisible heat; in 1681 the pioneering experimenter Edme Mariotte showed that glass, though transparent to sunlight, obstructed radiant heat. In 1800 the astronomer Sir William Herschel discovered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pit Organ
The ability to sense infrared thermal radiation evolved independently in two different groups of snakes, one consisting of the families Boidae (boas) and Pythonidae (pythons), the other of the family Crotalinae (pit vipers). What is commonly called a pit organ allows these animals to essentially "see" radiant heat at wavelengths between 5 and 30 μm. The more advanced infrared sense of pit vipers allows these animals to strike prey accurately even in the absence of light, and detect warm objects from several meters away. It was previously thought that the organs evolved primarily as prey detectors, but recent evidence suggests that it may also be used in thermoregulation and predator detection, making it a more general-purpose sensory organ than was supposed.Greene HW. 1992. The ecological and behavioral context for pitviper evolution. ''In'' Campbell JA, Brodie ED Jr. 1992. Biology of the Pitvipers. Texas: Selva. 467 pp. 17 plates. . Phylogeny and evolution The facial pit un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Projectile Use By Living Systems
Although projectiles are commonly used in human conflict, projectile use by organisms other than humans is relatively rare. Animals Liquid projectiles Most projectiles used by terrestrial animals are liquids. Among invertebrates there are a number of examples. Velvet worms can squirt out an slimy adhesive fluid from glands on the sides of their head, and use it to trap their prey. The spitting spiders ''Scytodes'' can spit a venomous sticky fluid that traps its victims and also poisons them. The bombardier beetle is unusual by using a violent exothermic chemical reaction to launch a boiling noxious chemical spray in a rapid burst of pulses from special glands in its abdomen, accompanied with a popping sound. The ''Anthia'' (oogpister beetle) will fire formic acid at attackers, probably extracting the formic acid from the ants that it eats. The devil-rider stick insects ('' Anisomorpha'') can fire terpenes from glands on the metathorax that can cause an intense burning irritati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snake Venom
Snake venom is a highly toxic saliva containing zootoxins that facilitates in the immobilization and digestion of prey. This also provides defense against threats. Snake venom is injected by unique fangs during a bite, whereas some species are also able to spit venom. The glands that secrete zootoxins are a modification of the parotid salivary glands found in other vertebrates and are usually located on each side of the head, below and behind the eye, and enclosed in a muscular sheath. The venom is stored in large glands called alveoli in which it's stored before being conveyed by a duct to the base of channeled or tubular fangs through which it's ejected. Venom contains more than 20 different compounds, which are mostly proteins and polypeptides. The complex mixture of proteins, enzymes, and various other substances has toxic and lethal properties. Venom serves to immobilize prey. Enzymes in venom play an important role in the digestion of prey, and various other substances ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of California, Davis
The University of California, Davis (UC Davis, UCD, or Davis) is a public land-grant research university near Davis, California. Named a Public Ivy, it is the northernmost of the ten campuses of the University of California system. The institution was first founded as an agricultural branch of the system in 1905 and became the seventh campus of the University of California in 1959. The university is classified among "R1: Doctoral Universities – Very high research activity". The UC Davis faculty includes 23 members of the National Academy of Sciences, 30 members of the American Academy of Arts and Sciences, 17 members of the American Law Institute, 14 members of the Institute of Medicine, and 14 members of the National Academy of Engineering. Among other honors that university faculty, alumni, and researchers have won are two Nobel Prizes, one Fields Medal, a Presidential Medal of Freedom, three Pulitzer Prizes, three MacArthur Fellowships, and a National Medal of Scien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rattlesnake
Rattlesnakes are venomous snakes that form the genera ''Crotalus'' and ''Sistrurus'' of the subfamily Crotalinae (the pit vipers). All rattlesnakes are vipers. Rattlesnakes are predators that live in a wide array of habitats, hunting small animals such as birds and rodents. Rattlesnakes receive their name from the rattle located at the end of their tails, which makes a loud rattling noise when vibrated that deters predators or serves as a warning to passers-by. Rattlesnakes are the leading contributor to snakebite injuries in North America, but rarely bite unless provoked or threatened; if treated promptly, the bites are seldom fatal. The 36 known species of rattlesnakes have between 65 and 70 subspecies, all native to the Americas, ranging from British Columbia through Ontario in southern Canada, to central Argentina. The largest rattlesnake, the eastern diamondback, can measure up to in length. Rattlesnakes are preyed upon by hawks, weasels, king snakes, and a variety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otospermophilus Beecheyi - Bleached Skull
''Otospermophilus'' is a genus of ground squirrels in the family Sciuridae, containing three species from Mexico and the United States. ''Otospermophilus'' was formerly placed in the large ground squirrel genus ''Spermophilus'', as a subgenus or species group. Since DNA sequencing of the cytochrome ''b'' gene has shown ''Spermophilus'' to be paraphyletic to the prairie dogs and marmots, it is now separated, along with six other genera. Species The three species in ''Otospermophilus'' are listed below. These are the same species that were previously grouped in the subgenus ''Otospermophilus''. :* Rock squirrel, ''Otospermophilus variegatus'' :* California ground squirrel, ''Otospermophilus beecheyi'' :* Baja California rock squirrel The Baja California rock squirrel (''Otospermophilus atricapillus'') is a species of rodent in the family Sciuridae. It is endemic to Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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