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Yellow-pine Chipmunk
The yellow-pine chipmunk (''Neotamias amoenus'') is a species of order Rodentia in the family Sciuridae. It is found in parts of Canada and the United States. These chipmunks are normally found in brush-covered areas, and in California, they inhabit an elevation range of around 975 to 2,900 meters. Description Their body color is dark and reddish, mixed with cinnamon, with five longitudinal dark (black or mixed black) stripes that are separated by four lighter stripes. The outer pair of pale stripes is creamy white and narrower, and the more median pair is a gray or smoke gray. The sides of the head each have three dark stripes, with two lighter in between, and the crown is black or smoke gray. Males and females have similar brain size and roughly the same tail length, ear length from notch, and length of lower tooth row, but females are larger in other body measurements; average body mass varies, with large males weighing an average of 49.7 g and large females averaging 53.5 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joel Asaph Allen
Joel Asaph Allen (July 19, 1838 – August 29, 1921) was an American zoology, zoologist, mammalogy, mammalogist, and ornithology, ornithologist. He became the first president of the American Ornithologists' Union, the first curator of birds and mammals at the American Museum of Natural History, and the first head of that museum's Department of Ornithology. He is remembered for Allen's rule, which states that the bodies of endotherms (warm-blooded animals) vary in shape with climate, having increased surface area in hot climates to lose heat, and minimized surface area in cold climates, to conserve heat. Early life Allen was born in Springfield, Massachusetts, the son of Joel Allen and Harriet Trumbull. He studied and collected specimen of natural history early in life, but he was forced to sell his relatively large collection so that he could attend the Wilbraham & Monson Academy in 1861. The following year, he transferred to Harvard University, where he studied under Louis Agassi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodent
Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal species are rodents. They are native to all major land masses except for 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/ricochetal (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 Mouse, mice, rats, squirrels, prairie dogs, porcupines, beavers, Cavia, guinea pigs, and hamsters. Once included wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sciuridae
Squirrels are members of the family Sciuridae (), a family that includes small or medium-sized rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squirrels are indigenous to the Americas, Eurasia, and Africa, and were introduced by humans to Australia. The earliest known fossilized squirrels date from the Eocene epoch, and among other living rodent families, the squirrels are most closely related to the mountain beaver and dormice. Etymology The word ''squirrel'', first attested in 1327, comes from the Anglo-Norman which is from the Old French , the reflex of a Latin language">Latin word , which was taken from the Ancient Greek word (; from ) 'shadow-tailed', referring to the long bushy tail which many of its members have. ''Sciurus'' is also the name of one of its genuses. The native Old English language, Old English word for the squirrel, , only survived into Middle Eng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Dimorphism
Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, dioecious species, which consist of most animals and some plants. Differences may include secondary sex characteristics, size, weight, color, markings, or behavioral or cognitive traits. Male-male reproductive competition has evolved a diverse array of sexually dimorphic traits. Aggressive utility traits such as "battle" teeth and blunt heads reinforced as battering rams are used as weapons in aggressive interactions between rivals. Passive displays such as ornamental feathering or song-calling have also evolved mainly through sexual selection. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', when both biological sexes are phenotype, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Least Chipmunk
The least chipmunk (''Neotamias minimus'') is the smallest species of chipmunk and the most widespread in North America. Description It is the smallest species of chipmunk, measuring about in total length with a weight of . The body is gray to reddish-brown on the sides, and grayish white on the underparts. The back is marked with five dark brown to black stripes separated by four white or cream-colored stripes, all of which run from the nape of the neck to the base of the tail. Two light and two dark stripes mark the face, running from the tip of the nose to the ears. The bushy tail is orange-brown in color, and measures long. In some areas, where range overlap with the yellow-pine chipmunk occurs, it may be difficult or impossible to distinguish the two species in the field; laboratory examination of skeletal structures may be required. As in other chipmunks, there are four toes on each of the forefeet and five on the hindfeet. Females have eight teats. The brain to body m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red-tailed Chipmunk
The red-tailed chipmunk (''Neotamias ruficaudus'') is a species of rodent in the family Sciuridae. It is found in Alberta and British Columbia in Canada and Montana, Idaho and Washington in the United States. Description The red-tailed chipmunk is a large species with a total length of about including a bushy tail of . The mass varies from about in the spring to in the fall. Females are marginally larger than males. The head is mottled grayish-brown with dark stripes above, through and below the eye. The body is basically orange-brown with five blackish stripes separated by four pale gray, tawny or cream-colored ones. The shoulders, sides, rump and flanks are tawny or buff. The underparts are creamy-white suffused with pinkish-buff. The upper side of the tail is black suffused with pinkish-buff and the underside is tawny tipped with pinkish-buff. In winter the animal's color is greyer and less tawny. In some areas, where range overlap with the yellow-pine chipmunk occurs, it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hibernation
Hibernation is a state of minimal activity and metabolic reduction entered by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It is most commonly used to pass through winter months – called overwintering. Although traditionally reserved for "deep" hibernators such as rodents, the term has been redefined to include animals such as bears and is now applied based on active metabolic suppression rather than any absolute decline in body temperature. Many experts believe that the processes of daily torpor and hibernation form a continuum and use similar mechanisms. The equivalent during the summer months is aestivation. Hibernation functions to conserve energy when sufficient food is not available. To achieve this energy saving, an endothermic animal decreases its metabolic rate and thereby its body temperature. Hibernation may last days, weeks, or months—depending on t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baculum
The baculum (: bacula), also known as the penis bone, penile bone, ''os penis'', ''os genitale'', or ''os priapi'', is a bone in the penis of many placental mammals. It is not present in humans, but is present in the penises of some primates, such as the gorilla and the chimpanzee. The baculum arises from primordial cells in soft tissues of the penis, and its formation is largely influenced by androgens. The bone lies above the male urethra, urethra, and it aids sexual reproduction by maintaining stiffness during sexual penetration. The Homology (biology), homologue to the baculum in female mammals is the baubellum (''os clitoridis''), a bone in the clitoris. Etymology The word ''baculum'' means "stick" or "staff" in Latin and originates from , ''baklon'' "stick". Function The baculum is used for copulation and varies in size and shape by species. Its evolution may be influenced by sexual selection, and its characteristics are sometimes used to differentiate between simila ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Os Clitoridis
The os clitoridis (also called the os clitoris, clitoral bone or baubellum; : baubella) is a bone inside the clitoris of many placental mammals. It is absent from the human clitoris, but present in clitoris#Non-human primates, the clitoris of some primates, such as ring-tailed lemurs and non-human great apes. However, in the latter case, the bone is greatly reduced in size. It is homologous to the baculum in male mammals. The structure is more evolutionarily labile than the baculum, exhibiting both more inherent variability and more gains and losses over time, which has been interpreted as evidence for its non-functionality. Other work posits that the variation in the os clitoridis could be driven by intersexual conflict, lock-and-key genital evolution, and cryptic female choice, especially given the high level of variation within species as well as between them. History The os clitoridis was described in 1666 by Claude Perrault in otters and in the lioness. The term ''os clit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estrous Cycle
The estrous cycle (, originally ) is a set of recurring physiological changes induced by reproductive hormones in females of mammalian subclass Theria. Estrous cycles start after sexual maturity in females and are interrupted by anestrous phases, otherwise known as "rest" phases, or by pregnancies. Typically, estrous cycles repeat until death. These cycles are widely variable in duration and frequency depending on the species.Bronson, F. H., 1989. Mammalian Reproductive Biology. University of Chicago Press, Chicago, IL, USA. Some animals may display bloody vaginal discharge, often mistaken for menstruation. Many mammals used in commercial agriculture, such as cattle and sheep, may have their estrous cycles artificially controlled with hormonal medications for optimum productivity. The male equivalent, seen primarily in ruminants, is called rut. Differences from the menstrual cycle Mammals share the same reproductive system, including the regulatory hypothalamic system that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neotamias
''Neotamias'' is a genus of chipmunks within the tribe Marmotini of the squirrel family. It contains 23 species, which mostly occur in western North America. Along with '' Eutamias'', this genus is often considered a subgenus of ''Tamias ''Tamias'' is a genus of chipmunks in the tribe Marmotini of the squirrel family. The genus includes a single living species, the eastern chipmunk (''Tamias striatus''). The genus name ''Tamias'' () means "treasurer", "steward", or "housekeeper ...''. Species * Alpine chipmunk, ''Neotamias alpinus'' * Yellow-pine chipmunk, ''Neotamias amoenus'' * Buller's chipmunk, ''Neotamias bulleri'' * Gray-footed chipmunk, ''Neotamias canipes'' * Gray-collared chipmunk, ''Neotamias cinereicollis'' * Cliff chipmunk, ''Neotamias dorsalis'' * Durango chipmunk, ''Neotamias durangae'' * Merriam's chipmunk, ''Neotamias merriami'' * Least chipmunk, ''Neotamias minimus'' * California chipmunk, ''Neotamias obscurus'' * Yellow-cheeked chipmunk, ''Neotamias ochro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals Described In 1890
A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors diverged in the Carboniferous Period over 300 million years ago. Around 6,640 extant species of mammals have been described and divided into 27 orders. The study of mammals is called mammalogy. The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, moles and shrews). The next three are the primates (including humans, monkeys and lemurs), the even-toed ungulates (including pigs, camels, and whales), and the Carnivora (including cats, Canidae, dogs, and Pinniped, seals). Mammals are the only living members of Synapsida; this clade, together with Sauropsida (reptiles and birds), co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
