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Gestation Periods
This is a collection of lists of mammal gestation period estimated by experts in their fields. The mammals included are only viviparous ( marsupials and placentals) as some mammals, which are monotremes (including platypuses and echidnas) lay their eggs. A marsupial has a short gestation period, typically shorter than placental. For more information on how these estimates were ascertained, see Wikipedia’s articles on gestational age. The gestation figures given here are shown in days. They represent average values and should only be considered as approximations. Factors affecting the gestation period in mammals There are several factors affecting the length of the gestation period in mammals. Animal size/mass There is a positive relationship between mass at birth and length of gestation in eutherian mammals. Larger mammals are more likely to produce a well-developed neonate than small mammals. Large mammals develop at an absolute slower rate compared to small mammals. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together with Saur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sable Antelope
The sable antelope (''Hippotragus niger'') is an antelope which inhabits wooded savanna in East and Southern Africa, from the south of Kenya to South Africa, with a separate population in Angola. Taxonomy The sable antelope shares the genus ''Hippotragus'' with the extinct bluebuck (''H. leucophaeus'') and the roan antelope (''H. equinus''), and is a member of the family Bovidae. In 1996, an analysis of mitochondrial DNA extracted from a mounted specimen of the bluebuck showed that it is outside the clade containing the roan and sable antelopes. The cladogram below shows the position of the sable antelope among its relatives, following the 1996 analysis: Subspecies ''Hipotragus niger'' has four subspecies: * The southern sable antelope (''H. n. niger''; also known as the common sable antelope, black sable antelope, Matsetsi sable antelope or South Zambian sable antelope) is regarded as the nominate subspecies, as it was the first one to be described and named in 1838. Often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bonobo
The bonobo (; ''Pan paniscus''), also historically called the pygmy chimpanzee and less often the dwarf chimpanzee or gracile chimpanzee, is an endangered great ape and one of the two species making up the genus '' Pan,'' the other being the common chimpanzee (''Pan troglodytes''). While bonobos are now recognized as a distinct species in their own right, they were initially thought to be a subspecies of chimpanzee (''Pan troglodytes)'' due to the physical similarities between the two species. Taxonomically, the members of the chimpanzee/bonobo subtribe Panina (composed entirely by the genus '' Pan'') are collectively termed ''panins''. The bonobo is distinguished by relatively long legs, pink lips, dark face, tail-tuft through adulthood, and parted long hair on its head. The bonobo is found in a area of the Congo Basin in the Democratic Republic of the Congo, Central Africa. The species is frugivorous and inhabits primary and secondary forests, including seasonally inundated sw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wild Boar
The wild boar (''Sus scrofa''), also known as the wild swine, common wild pig, Eurasian wild pig, or simply wild pig, is a suid native to much of Eurasia and North Africa, and has been introduced to the Americas and Oceania. The species is now one of the widest-ranging mammals in the world, as well as the most widespread suiform. It has been assessed as least concern on the IUCN Red List due to its wide range, high numbers, and adaptability to a diversity of habitats. It has become an invasive species in part of its introduced range. Wild boars probably originated in Southeast Asia during the Early Pleistocene and outcompeted other suid species as they spread throughout the Old World. , up to 16 subspecies are recognized, which are divided into four regional groupings based on skull height and lacrimal bone length. The species lives in matriarchal societies consisting of interrelated females and their young (both male and female). Fully grown males are usually solitary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beaver
Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers are the second-largest living rodents after the capybaras. They have stout bodies with large heads, long chisel-like incisors, brown or gray fur, hand-like front feet, webbed back feet and flat, scaly tails. The two species differ in the shape of the skull and tail and fur color. Beavers can be found in a number of freshwater habitats, such as rivers, streams, lakes and ponds. They are herbivorous, consuming tree bark, aquatic plants, grasses and sedges. Beavers build dams and lodges using tree branches, vegetation, rocks and mud; they chew down trees for building material. Dams impound water and lodges serve as shelters. Their infrastructure creates wetlands used by many other species, and because of their effect on other organisms in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Bear
The polar bear (''Ursus maritimus'') is a hypercarnivorous bear whose native range lies largely within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the largest extant bear species, as well as the largest extant land carnivore. A boar (adult male) weighs around , while a sow (adult female) is about half that size. Although it is the sister species of the brown bear, it has evolved to occupy a narrower ecological niche, with many body characteristics adapted for cold temperatures, for moving across snow, ice and open water, and for hunting seals, which make up most of its diet. Although most polar bears are born on land, they spend most of their time on the sea ice. Their scientific name means "maritime bear" and derives from this fact. Polar bears hunt their preferred food of seals from the edge of sea ice, often living off fat reserves when no sea ice is present. Because of their dependence on the sea ice, polar be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grizzly
The grizzly bear (''Ursus arctos horribilis''), also known as the North American brown bear or simply grizzly, is a population or subspecies of the brown bear inhabiting North America. In addition to the mainland grizzly (''Ursus arctos horribilis''), other morphological forms of brown bear in North America are sometimes identified as grizzly bears. These include three living populations—the Kodiak bear (''U. a. middendorffi''), the Kamchatka brown bear, Kamchatka bear (''U. a. beringianus''), and the Alaska Peninsula brown bear, peninsular grizzly (''U. a. gyas'')—as well as the extinct California grizzly bear, California grizzly (''U. a. californicus''†), Mexican grizzly bear, Mexican grizzly (formerly ''U. a. nelsoni''†), and Ungava brown bear, Ungava-Labrador grizzly (formerly ''U. a. ungavaesis''†). On average, grizzly bears near the coast tend to be larger while inland grizzlies tend to be smaller. The Ussuri brown bear (''U. a. lasiotus''), inhabiting Russia, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Black Bear
The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but will leave forests in search of food, and are sometimes attracted to human communities due to the immediate availability of food. The International Union for Conservation of Nature (IUCN) lists the American black bear as a least-concern species, due to its widespread distribution and a large population estimated to be twice that of all other bear species combined. Along with the brown bear (''Ursus arctos''), it is one of only two modern bear species not considered by the IUCN to be globally threatened with extinction. Taxonomy and evolution Despite living in North America, American black bears are not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bear
Bears are carnivoran mammals of the family Ursidae. They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout the Northern Hemisphere and partially in the Southern Hemisphere. Bears are found on the continents of North America, South America, Europe, and Asia. Common characteristics of modern bears include large bodies with stocky legs, long snouts, small rounded ears, shaggy hair, plantigrade paws with five nonretractile claws, and short tails. While the polar bear is mostly carnivorous, and the giant panda feeds almost entirely on bamboo, the remaining six species are omnivorous with varied diets. With the exception of courting individuals and mothers with their young, bears are typically solitary animals. They may be diurnal or nocturnal and have an excellent sense of smell. Despite their heavy build and awkward gait, they are adept runners, cli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Badger
The American badger (''Taxidea taxus'') is a North American badger similar in appearance to the European badger, although not closely related. It is found in the western, central, and northeastern United States, northern Mexico, and south-central Canada to certain areas of southwestern British Columbia. The American badger's habitat is typified by open grasslands with available prey (such as mice, squirrels, and groundhogs). The species prefers areas such as prairie regions with sandy loam soils where it can dig more easily for its prey. Taxonomy The American badger is a member of the Mustelidae, a diverse family of carnivorous mammals that also includes weasels, otters, ferrets, and the wolverine. The American badger belongs to the Taxidiinae, one of four subfamilies of mustelid badgers – the other three being the Melinae (four species in two genera, including the European badger), the Helictidinae (five species of ferret-badgers) and the Mellivorinae (the honey badger); th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Badger
Badgers are short-legged omnivores in the family Mustelidae (which also includes the otters, wolverines, martens, minks, polecats, weasels, and ferrets). Badgers are a polyphyletic rather than a natural taxonomic grouping, being united by their squat bodies and adaptions for fossorial activity. All belong to the caniform suborder of carnivoran mammals. The fifteen species of mustelid badgers are grouped in four subfamilies: four species of Melinae (genera ''Meles'' and ''Arctonyx'') including the European badger, five species of Helictidinae (genus ''Melogale'') or ferret-badger, the honey badger or ratel Mellivorinae (genus ''Mellivora''), and the American badger Taxideinae (genus ''Taxidae''). Badgers include the most basal mustelids; the American badger is the most basal of all, followed successively by the ratel and the Melinae; the estimated split dates are about 17.8, 15.5 and 14.8 million years ago, respectively. The two species of Asiatic stink badgers of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baboon
Baboons are primates comprising the genus ''Papio'', one of the 23 genera of Old World monkeys. There are six species of baboon: the hamadryas baboon, the Guinea baboon, the olive baboon, the yellow baboon, the Kinda baboon and the chacma baboon. Each species is native to one of six areas of Africa and the hamadryas baboon is also native to part of the Arabian Peninsula. Baboons are among the largest non-hominoid primates and have existed for at least two million years. Baboons vary in size and weight depending on the species. The smallest, the Kinda baboon, is in length and weighs only , while the largest, the chacma baboon, is up to in length and weighs . All baboons have long, dog-like muzzles, heavy, powerful jaws with sharp canine teeth, close-set eyes, thick fur except on their muzzles, short tails, and nerveless, hairless pads of skin on their protruding buttocks called ischial callosities that provide for sitting comfort. Male hamadryas baboons have large white man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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