Short-tailed Chinchilla
The short-tailed chinchilla (''Chinchilla chinchilla)'' is a small rodent part of the Chinchillidae family and is classified as an endangered species by the IUCN. Originating in South America, the chinchilla is part of the genus ''Chinchilla'', which is separated into two species: the long-tailed chinchilla and the short-tailed chinchilla. Although the short-tailed chinchilla used to be found in Chile, Argentina, Peru, and Bolivia, the geographical distribution of the species has since shifted. Today, the species remains extant in the Andes mountains of northern Chile, but small populations have been found in southern Bolivia. The short-tailed chinchilla is characterized by its grayish-blue fur which is extremely dense and plush. The short-tailed chinchilla has a short furry tail, which distinguishes it from the long-tailed chinchilla. Compared to '' C. lanigera, C. chinchilla'' has smaller, more rounded ears and is slightly smaller in body size. Chinchillas have been exploited ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Hinrich Lichtenstein
Martin H[e]inrich Carl Lichtenstein (10 January 1780 – 2 September 1857) was a German physician, List of explorers, explorer, botanist and zoologist. He explored parts of southern Africa and collected natural history specimens extensively and many new species were described from his collections by European scientists. Biography Born in Hamburg, Lichtenstein was the son of Anton August Heinrich Lichtenstein, head of the Gelehrtenschule des Johanneums, Johanneum. His father had an interest in eastern languages and built up an extensive library. He took an interest in natural history and geography from an early age, and came into contact with Count Johann Centurius Hoffmannsegg, Johann Centurius von Hoffmannsegg in 1797 and began to help examine the Count's extensive collections of insects and birds. He then went to study medicine at University of Jena, Jena and University of Helmstedt, Helmstedt and qualified as a doctor on 26 April 1802. He then chose to travel and found work ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Vestigiality
Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on comparison with homology (biology), homologous features in related species. The emergence of vestigiality occurs by normal evolutionary processes, typically by loss of function of a feature that is no longer subject to Directional selection, positive Evolutionary pressure, selection pressures when it loses its value in a changing environment. The feature may be Negative selection (natural selection), selected against more urgently when its function becomes definitively harmful, but if the lack of the feature provides no advantage, and its presence provides no disadvantage, the feature may not be phased out by natural selection and persist across species. Examples of vestigial structures (also called degenerate, atrophied, or rudimentary orga ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Animal Communication
Animal communication is the transfer of information from one or a group of animals (sender or senders) to one or more other animals (receiver or receivers) that affects the current or future behavior of the receivers. Information may be sent intentionally, as in a courtship display, or unintentionally, as in the transfer of scent from the predator to prey with kairomones. Information may be transferred to an "audience" of several receivers. Animal communication is a rapidly growing area of study in disciplines including Ethology, animal behavior, sociology, neurology, and animal cognition. Many aspects of animal behavior, such as symbolic name use, emotional expression, learning, and Animal sexual behavior, sexual behavior, are being understood in new ways. When the information from the sender changes the behavior of a receiver, the information is referred to as a "signal". Signalling theory predicts that for a signal to be maintained in the population, both the sender and receiv ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Sexual Maturity
Sexual maturity is the capability of an organism to reproduce. In humans, it is related to both puberty and adulthood. ''Puberty'' is the biological process of sexual maturation, while ''adulthood'', the condition of being socially recognized as an independent person capable of giving consent and taking responsibility, generally implies sexual maturity (certain disorders of sexual development notwithstanding), but depends on other criteria, defined by specific cultural expectations. Most multicellular organisms are unable to sexually reproduce at birth (animals) or germination (e.g. plants): depending on the species, it may be days, weeks, or years until they have developed enough to be able to do so; in addition, certain cues may trigger an organism to become sexually mature. These may be external, such as drought, or fire, that triggers sexual maturation of certain plants, or internal, such as percentage of body fat (certain animals). Internal cues are not to be confused ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Litter (zoology)
A litter is the live birth of multiple offspring at one time in animals from the same mother and usually from one set of parents, particularly from three to eight offspring. The word is most often used for the offspring of mammals, but can be used for any animal that gives birth to multiple young. In comparison, a group of egg (biology), eggs and the offspring that hatch from them are frequently called a clutch (animal), clutch, while young birds are often called a offspring, brood. Animals from the same litter are referred to as littermates. Litter size (typical count) In most female mammals the average litter size is about half the number of mammae. Presumably this enables females to successfully nurse litters even if some mammae fail to produce milk. Naked mole-rats break this "one-half rule" – field caught and lab born litters averaged 11 to 12 pups, and numbers of mammae on wild and captive females were similarly 11 to 12. Maximum litter sizes were 28 in the field and ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregnancy can have one or more gestations at the same time, for example in a multiple birth. The time interval of a gestation is called the '' gestation period''. In obstetrics, '' gestational age'' refers to the time since the onset of the last menses, which on average is fertilization age plus two weeks. Mammals In mammals, pregnancy begins when a zygote (fertilized ovum) implants in the female's uterus and ends once the fetus leaves the uterus during labor or an abortion (whether induced or spontaneous). Humans In humans, pregnancy can be defined clinically, biochemically or biologically. Clinically, pregnancy starts from first day of the mother's last period. Biochemically, pregnancy starts when a woman's human chorionic gonado ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Northern Hemisphere
The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar System as Earth's North Pole. Due to Earth's axial tilt of 23.439281°, there is a seasonal variation in the lengths of the day and night. There is also a seasonal variation in temperatures, which lags the variation in day and night. Conventionally, winter in the Northern Hemisphere is taken as the period from the December solstice (typically December 21 UTC) to the March equinox (typically March 20 UTC), while summer is taken as the period from the June solstice through to the September equinox (typically on 23 September UTC). The dates vary each year due to the difference between the calendar year and the Year#Astronomical years, astronomical year. Within the Northern Hemisphere, oceanic currents can change the weather patterns that aff ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Monogamy In Animals
Some animal species have a monogamous mating system, in which pairs bond to raise offspring. This is associated, usually implicitly, with sexual monogamy. Monogamous mating Monogamy is defined as a pair bond between two adult animals of the same species. This pair may cohabitate in an area or territory for some duration of time, and in some cases may copulate and reproduce with only each other. Monogamy may either be short-term, lasting one to a few seasons or long-term, lasting many seasons and in extreme cases, life-long. Monogamy can be partitioned into two categories, social monogamy and genetic monogamy which may occur together in some combination, or completely independently of one another.Ophir, Alexander G., Phelps, Steven M., Sorin, Anna Bess & O. Wolff, J. (2008)Social but not genetic monogamy is associated with greater breeding success in prairie voles/ref> As an example, in the cichlid species '' Variabilichromis moorii'', a monogamous pair will care for eggs and y ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Herd
A herd is a social group of certain animals of the same species, either wild or domestic. The form of collective animal behavior associated with this is called '' herding''. These animals are known as gregarious animals. The term ''herd'' is generally applied to mammals, and most particularly to the grazing ungulates that classically display this behaviour. Different terms are used for similar groupings in other species; in the case of birds, for example, the word is '' flocking'', but ''flock'' may also be used for mammals, particularly sheep or goats. Large groups of carnivores are usually called '' packs'', and in nature a herd is classically subject to predation from pack hunters. Special collective nouns may be used for particular taxa (for example a flock of geese, if not in flight, is sometimes called a ''gaggle'') but for theoretical discussions of behavioural ecology, the generic term ''herd'' can be used for all such kinds of assemblage. The word ''herd'', a ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Whiskers
Whiskers, also known as vibrissae (; vibrissa; ) are a type of stiff, functional hair used by most therian mammals to 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 nocturnal mammals. Monotremes, however, lack them. 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 sitti ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Hair Follicle
The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction between hormones, neuropeptides, and immune cells. This complex interaction induces the hair follicle to produce different types of hair as seen on different parts of the body. For example, terminal hairs grow on the scalp and lanugo hairs are seen covering the bodies of fetuses in the uterus and in some newborn babies. The process of hair growth occurs in distinct sequential stages: ''anagen'' is the active growth phase, ''catagen'' is the regression of the hair follicle phase, ''telogen'' is the resting stage, ''exogen'' is the active shedding of hair phase and ''kenogen'' is the phase between the empty hair follicle and the growth of new hair. The function of hair in humans has long been a subject of interest and continues to be an impor ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |