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Infanticide In Rodents
Infanticide (zoology), Infanticide is the termination of a neonate after it has been born, and in infanticide (zoology), zoology this is often the termination or consumption of newborn animals by either a parent or an unrelated adult. In rodents, it is not uncommon for the mother to commit infanticide shortly after parturition (giving birth) under conditions of extreme stress (parental infanticide), or for an unrelated male to kill neonates (nonparental infanticide). Parental infanticide Parental infanticide is perhaps the most confusing behaviour to understand, as in many cases it can seem maladaptive for a parent to terminate offspring carrying its own genetic material. However, studies in mice have indicated infanticide may be a genetically heritable trait, and may even have a learned element, so there is clearly more to the behaviour than might be expected. The occurrence of infanticide seems to vary within rodent species between parents. For example, male meadow voles and hous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactating
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The process of feeding milk in all female creatures is called ''nursing'', and in humans it is also called ''breastfeeding''. Newborn infants often produce some milk from their own breast tissue, known colloquially as witch's milk. In most species, lactation is a sign that the female has been pregnant at some point in her life, although in humans and goats, it can happen without pregnancy. Nearly every species of mammal has teats; except for monotremes, egg-laying mammals, which instead release milk through ducts in the abdomen. In only a handful of species of mammals, certain bat species, is milk production a normal male function. ''Galactopoiesis'' is the maintenance of milk production. This stage requires prolactin. Oxytocin is critical for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
13-lined Ground Squirrel
The thirteen-lined ground squirrel (''Ictidomys tridecemlineatus''), also known as the striped gopher, leopard ground squirrel, and squinny (formerly known as the leopard-spermophile in the age of Audubon), is a species of hibernating ground squirrel that is widely distributed over grasslands and prairies of North America. Description It is brownish, with 13 alternating brown and whitish longitudinal lines (sometimes partially broken into spots) on its back and sides, creating rows of whitish spots within dark lines. Taxonomy This species has usually been placed in the genus ''Spermophilus'' with about 40 other species. As this large genus is paraphyletic to prairie dogs, marmots, and antelope squirrels, Kristofer Helgen and colleagues have split it into eight genera, placing the thirteen-lined ground squirrel in ''Ictidomys'' with two other species. Behavior The thirteen-lined ground squirrel is strictly diurnal and is especially active on warm days. A solitary or on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franklin's Ground Squirrel
Franklin's ground squirrel (''Poliocitellus franklinii'') is a species of squirrel native to North America, and the only member of the genus ''Poliocitellus''. Due to the destruction of prairie, the populations of Franklin's ground squirrel have dwindled, approaching levels of concern. Its decline in the eastern portion of its range is mostly attributed to habitat fragmentation. Taxonomy Franklin's ground squirrel was first described by Joseph Sabine in 1822, who named it in honor of the British Arctic explorer Sir John Franklin. It was formerly placed in the large ground squirrel genus ''Spermophilus'', in its own subgenus, ''Poliocitellus'', but since DNA sequencing of the cytochrome ''b'' gene has shown ''Spermophilus'' to be paraphyletic it is now placed in its own genus. Franklin's ground squirrel is suggested to be sister to a clade containing not only the Mohave, round-tailed, spotted, and Perote ground squirrels (genus ''Xerospermophilus''), but the prairie dogs as we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yellow-bellied Marmot
The yellow-bellied marmot (''Marmota flaviventer''), also known as the rock chuck, is a large, stout-bodied ground squirrel in the marmot genus. It is one of fourteen species of marmots, and is native to mountainous and semi-arid regions of southwestern Canada and western United States, including the Rocky Mountains, Sierra Nevada (U.S.), Sierra Nevada, and the Great Basin, often (but not exclusively) living above . The fur is mainly brown, with a dark bushy tail, yellow chest and white patch between the eyes, and they weigh up to approximately . They are highly social creatures, living in burrows in Colony (biology), colonies of up to twenty individuals. They are diurnal and feed on plant material, insects, and bird eggs. They Hibernation, hibernate for approximately eight months starting in September and lasting through the winter. They have an average lifespan of 15 years. Description Yellow-bellied marmots usually weigh from when fully grown, though males typically weigh m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpine Marmot
The alpine marmot (''Marmota marmota'') is a large ground-dwelling squirrel, from the genus of marmots. It is found in high numbers in mountainous areas of central and southern Europe, at heights between in the Alps, Carpathians, Tatras and Northern Apennines. In 1948 they were reintroduced with success in the Pyrenees, where the alpine marmot had disappeared at end of the Pleistocene epoch. Evolution The alpine marmot originates as an animal of Pleistocene cold steppe, exquisitely adapted to this ice-age climate. As such, alpine marmots are excellent diggers, able to penetrate soil that even a pickaxe would have difficulty with, and spend up to nine months per year in hibernation. Since the disappearance of the Pleistocene cold steppe, the alpine marmot persists in the high altitude alpine meadow. During the colonisation of Alpine habitat, the alpine marmot has lost most of its genetic diversity through a bottleneck effect. It could not rebuild its genetic diversity ever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golden Marmot
The long-tailed marmot (''Marmota caudata'') or golden marmot is a marmot species in the family Sciuridae. It occurs in mountainous regions in the central parts of Asia where it lives in open or lightly wooded habitats, often among rocks where dwarf junipers grow. It is IUCN Red Listed as Least Concern. As suggested by its name, it is a relatively long-tailed species of marmot. Description The long-tailed marmot is a large, sturdy rodent weighing up to . Its typical weight range is from , with the lower weights in the spring directly after hibernation and the higher weights in the autumn just before hibernation where more than one–quarter of its mass can be fat. Males average slightly larger than females. Its head-and-body length is and the tail is about long. The tail is 37–55% of the head-and-body length. This is considerably longer than typical of other marmots, although the proportionally longest-tailed individuals of the grey (''M. baibacina'') and alpine marmots (''M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
California Ground Squirrel
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tree Squirrel
Tree squirrels are the members of the squirrel Family (biology), family (Sciuridae) commonly just referred to as "squirrels". They include more than 100 arboreal species native to all continents except Antarctica and Oceania. They do not form a single natural, or monophyly, monophyletic, group; they are variously related to others in the squirrel family, including ground squirrels, flying squirrels, marmots, and chipmunks. The defining characteristic used to determine which species of Sciuridae are tree squirrels is dependent on their habitat rather than their physiology. Tree squirrels live mostly among trees, as opposed to those that live in burrows in the ground or among rocks. An exception is the flying squirrel that also makes its home in trees, but has a physiological distinction separating it from its tree squirrel cousins: special flaps of skin called patagia, acting as glider wings, which allow gliding flight. The best-known genus of tree squirrels is ''Sciurus'', which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caviomorpha
Caviomorpha is the rodent parvorder that unites all New World hystricognaths. It is supported by both fossil and molecular evidence. The Caviomorpha was for a time considered to be a separate order outside the Rodentia, but is now accepted as a genuine part of the rodents. Caviomorphs include the extinct Heptaxodontidae (giant hutias), the extinct '' Josephoartigasia monesi'' (the largest rodent ever known) and extant families of chinchilla rats, hutias, guinea pigs and the capybara, chinchillas and viscachas, tuco-tucos, agoutis, pacas, pacaranas, spiny rats, New World porcupines, coypu and octodonts (Vassallo and Antenucci, 2015). Origin The first known rodent fossils in South America are represented by the three taxa ''Cachiyacuy contamanensis'', ''C. kummeli'', and ''Canaanimys maquiensis'', as well as teeth from ''Eobranisamys'' sp. (Dasyproctidae) and ''Eospina'' sp., the latter two found also in the Santa Rosa fauna from the late Eocene or early Oligocen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myomorpha
The suborder Myomorpha contains 1,524 species of mouse-like rodents, nearly a quarter of all mammal species. Included are mice, rats, gerbils, hamsters, lemmings, and voles. They are grouped according to the structure of their jaws and molar teeth. They are characterized by their myomorphous zygomasseteric system, which means that both their medial and lateral masseter muscles are displaced forward, making them adept at gnawing. As in the hystricognathous rodents, the medial masseter muscle goes through the eye socket, a feature unique among mammals. Myomorphs are found worldwide (apart from Antarctica) in almost all land habitats. They are usually nocturnal seed-eaters. Most myomorph species belong to the superfamily Muroidea: (hamsters, voles, lemmings, true mice, true rats, and gerbils). *Superfamily Muroidea **Family Platacanthomyidae ( spiny dormice and Chinese pygmy dormice) **Family Spalacidae ( blind mole-rats and bamboo rats) **Family Calomyscidae ( mouse-lik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sciuromorpha
Sciuromorpha ( 'squirrel-like') is a rodent Order (biology), suborder that includes several rodent Family (biology), families. It includes all members of the Sciuridae (the squirrel family) as well as the mountain beaver species. Traditionally, the term has been defined on the basis of the shape of the infraorbital canal. A sciuromorphous zygomasseteric system is characterized by attachment of the lateral masseter muscle along the side of the snout, rostrum. Unlike hystricomorphous and myomorphous rodents, the medial masseter muscle does not pass through the infraorbital canal. Among extant rodents, only the families Sciuridae, Castoridae, Heteromyidae, and Geomyidae are truly sciuromorphous. Some authorities would exclude the Geomyidae and Heteromyidae from that list due to the attachment of the medial masseter directly behind the zygomatic arch. Carleton and Musser (2005) redefined the rodent suborders on Morphology (biology), morphological and Molecular phylogeny, molecu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
