Portal:Mammals

The Mammals portal A mammal (from Latin mamma 'breast') is a vertebrate animal of the class Mammalia (/məˈmeɪli.ə/). Mammals are characterized 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 6,400 extant species of mammals have been described and divided into 27 orders. The largest orders of mammals, by number of species, are the rodents, bats, and Eulipotyphla (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, dogs, and seals). Mammals are the only living members of Synapsida; this clade, together with Sauropsida (reptiles and birds), constitutes the larger Amniota clade. Early synapsids are referred to as "pelycosaurs." The more advanced therapsids became dominant during the Guadalupian. Mammals originated from cynodonts, an advanced group of therapsids, during the Late Triassic to Early Jurassic. Mammals achieved their modern diversity in the Paleogene and Neogene periods of the Cenozoic era, after the extinction of non-avian dinosaurs, and have been the dominant terrestrial animal group from 66 million years ago to the present. The basic mammalian body type is quadrupedal, with most mammals using four limbs for terrestrial locomotion; but in some, the limbs are adapted for life at sea, in the air, in trees or underground. The bipeds have adapted to move using only the two lower limbs, while the rear limbs of cetaceans and the sea cows are mere internal vestiges. Mammals range in size from the 30–40 millimetres (1.2–1.6 in) bumblebee bat to the 30 metres (98 ft) blue whale—possibly the largest animal to have ever lived. Maximum lifespan varies from two years for the shrew to 211 years for the bowhead whale. All modern mammals give birth to live young, except the five species of monotremes, which lay eggs. The most species-rich group is the viviparous placental mammals, so named for the temporary organ (placenta) used by offspring to draw nutrition from the mother during gestation. Most mammals are intelligent, with some possessing large brains, self-awareness, and tool use. Mammals can communicate and vocalize in several ways, including the production of ultrasound, scent marking, alarm signals, singing, echolocation; and, in the case of humans, complex language. Mammals can organize themselves into fission–fusion societies, harems, and hierarchies—but can also be solitary and territorial. Most mammals are polygynous, but some can be monogamous or polyandrous. Domestication of many types of mammals by humans played a major role in the Neolithic Revolution, and resulted in farming replacing hunting and gathering as the primary source of food for humans. This led to a major restructuring of human societies from nomadic to sedentary, with more co-operation among larger and larger groups, and ultimately the development of the first civilizations. Domesticated mammals provided, and continue to provide, power for transport and agriculture, as well as food (meat and dairy products), fur, and leather. Mammals are also hunted and raced for sport, kept as pets and working animals of various types, and are used as model organisms in science. Mammals have been depicted in art since Paleolithic times, and appear in literature, film, mythology, and religion. Decline in numbers and extinction of many mammals is primarily driven by human poaching and habitat destruction, primarily deforestation. (Full article...) Selected article The Sumatran Rhinoceros (Dicerorhinus sumatrensis) is a species of the family Rhinocerotidae, and one of five extant rhinoceri. It is the smallest rhinoceros, standing about 120–145 centimetres (3.9–4.8 ft) high at the shoulder, with a body length of 250 centimetres (98 in) and weight of 500–800 kilograms (1100–1760 lb). Like its African counterparts, the black and white rhinoceri, it has two horns; the larger is the nasal horn, typically 15–25 centimetres (6–10 in), while the other is typically a stub. A coat of reddish-brown hair covers most of the rhino's body. Members of the species once ranged throughout rainforests, swamps and cloud forests in India, Bhutan, Bangladesh, Myanmar, Laos, Thailand, Malaysia, and Indonesia. They are now critically endangered, with only six substantial populations in the wild: four on Sumatra, one on Borneo, and one on peninsular Malaysia. Their numbers are difficult to determine because they are solitary animals that are widely scattered across their range, but they are estimated to number around just 300. The decline in the number of Sumatran rhinoceri is attributed primarily to poaching for their ivory horns, which are highly valued in traditional Chinese medicine, fetching as much as US$30,000 per kilogram on the black market. The rhinos have also suffered from habitat loss as their forests have been cleared for lumber and conversion to agriculture. Did you know? ...that one burrow of the eastern chipmunk (pictured) was found to contain 390 acorns? .. that the Hare Indian dog, now extinct, was not known to bark, but puppies learned to imitate the barking of other dogs when the breed was introduced to Europe? ... that the rodents Thomasomys ucucha from Ecuador and Oxymycterus hucucha from Bolivia were both named after the local Quechua word for "mouse"? ...that the incisors of blesmols are visible even when their mouths are closed? ... that the pebble-mound mice of northern Australia construct mounds of stones around their burrows up to 10 m2 in area? ... that the stationmaster of the Kinokawa train station in Kinokawa, Japan was a cat named Tama? Related portals Selected images Yellow-bellied Marmot Photo credit: Inklein A Yellow-bellied Marmot seen on top of Mount Dana, Yosemite National Park, USA. The road in the background is Tioga Pass Road. Yellow-bellied Marmots are ground squirrels that live in the western United States and southwestern Canada. They inhabit steppes, meadows, talus fields and other open habitats, sometimes on the edge of deciduous or coniferous forests, and typically above 2,000 metres (6,562 ft) of elevation. Leopard Photograph credit: Diego Delso The leopard (Panthera pardus) is one of five extant species in the genus Panthera, a member of the cat family, Felidae. This photograph shows a leopard devouring an impala in Kruger National Park, South Africa. Compared to other wild cats, the leopard has a relatively large skull with powerful jaws, a long body and short legs. It can climb trees very skilfully, often rests on tree branches and can descend to the ground head first. An adult leopard is strong enough to drag a carcass heavier than itself up into a tree, where the prey may be eaten straight away or cached to be consumed later. Babirusa skull Photograph: Didier Descouens Skull of a male North Sulawesi babirusa, a species from the pig family endemic to Indonesia. Babirusas are notable for the long upper canines in the males that emerge vertically from the alveolar process, penetrating though the skin and curving backward over the front of the face and towards the forehead. Yellow mongoose Photo: Yathin S Krishnappa The yellow mongoose (Cynictis penicillata) is a small mammal averaging about 1 lb (1/2 kg) in weight and about 20 in (500 mm) in length. Found in southern Africa, it lives in flat areas ranging from semi-desert scrubland to grasslands. This carnivorous species lives in colonies of up to 20 individuals. Elephant portrait Photograph: Muhammad Mahdi Karim A portrait of an African elephant, highlighting its trunk. The trunk, which contains some 150,000 muscle fascicles, is a fusion of the nose and upper lip with a unique nerve running along both sides. An elephant can use its trunk for power functions, such as lifting up to 350 kg (770 lb), or more delicate functions, such as wiping its eye. Southern plains grey langur Photograph credit: Charles J. Sharp The southern plains gray langur (Semnopithecus dussumieri) is a species of Old World monkey native to the Indian subcontinent. It is about 62 cm (24 in) tall and lives in groups in various forest habitats, feeding mainly on leaves, fruit and flowers in the canopy, supplementing these with insects, gum, grasses, herbs and roots. The monkeys are considered sacred in India, and some are used by Hindu priests for religious purposes. They have adapted to living in close proximity to humans in urban settings; they are often fed by humans and accept cakes, millet, and other foods. The species is protected by law in India, but some are still persecuted for damaging crops, hunted for food and captured for pets. This photograph of a female southern plains gray langur was taken in Kanha Tiger Reserve, in the Indian state of Madhya Pradesh. The park was created on 1 June 1955 and was designated a tiger reserve in 1973. Japanese Squirrel Photo credit: Ma2bara The Japanese Squirrel (Sciurus lis) is a species of rodent in the Sciuridae family. It is endemic to Japan. Proboscis monkey Photograph credit: Charles James Sharp The proboscis monkey (Nasalis larvatus) is endemic to the island of Borneo, where it is found predominantly in coastal areas, near rivers and in swamp forests. It is perhaps the most aquatic of the primates and is a fairly good swimmer, capable of swimming underwater; apart from this, it is largely arboreal. This image is a composite of three photographs and shows a proboscis monkey jumping between trees in Labuk Bay in the Malaysian state of Sabah. Charolais bull Photograph: The Photographer A feral Charolais bull in the Sierra Nevada de Mérida, Venezuela. This breed of taurine beef cattle comes from the Charolais area in eastern France. Domestic Charolais are raised for meat, and may be crossed with other breeds, including Angus and Hereford cattle. Tabby cat Photo: Joaquim Alves Gaspar A tabby is any cat that has a distinctive coat that features stripes, dots, lines or swirling patterns, usually together with a mark resembling an "M" on its forehead. Tabbies are not a cat breed, but a coat pattern found in many breeds of cat, as well as among the general mixed-breed population. The tabby pattern may be related to the coloration of the domestic cat's direct ancestor, the African Wildcat, which (along with the European Wildcat and Asiatic Wildcat) has a similar coloration. There are four genetically distinct tabby patterns: mackerel (shown here), classic, spotted, and ticked. European Rabbit Photo: JJ Harrison The European Rabbit (Oryctolagus cuniculus) is a species of rabbit native to the Iberian Peninsula and Northwest Africa. It has been widely introduced to countries on all continents with the exception of Antarctica and Sub-Saharan Africa, often with devastating effects on local biodiversity. In Australia particularly, twelve pairs of rabbits introduced in 1859 became millions in just ten years, the fastest spread ever recorded of any mammal anywhere in the world. Short-beaked Echidna Photo credit: Fir0002 The Short-beaked Echidna (Tachyglossus aculeatus), also known as the Spiny Anteater because of its diet of ants and termites, is one of four living species of echidna. The species is found throughout Australia, where it is the most widespread native mammal, and in coastal and highland regions of southwestern New Guinea. Guinea baboon Photograph: William Warby A female and a juvenile guinea baboon (Papio papio) at Port Lympne Wild Animal Park, England. This species is native to dry forests, gallery forests, and adjoining bush savannas in western Africa. This diurnal animal is primarily terrestrial, but sleeps in trees at night. More than 200 individuals may be in the same troop, which is limited in size by the number of suitable sleeping trees. Polar bear Photograph credit: Andreas Weith 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. A boar (adult male) weighs around 350–750 kilograms (770–1,650 lb), while a sow (adult female) is about half that size. Polar bears are the largest land carnivores currently in existence, rivalled only by the omnivorous Kodiak bear. 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, as well as 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 sea ice. The species's scientific name, which is derived from this fact, means 'maritime bear'. Because of their dependence on sea ice, polar bears are categorized as marine mammals. Due to expected habitat loss caused by global warming, the polar bear is classified as a vulnerable species. For decades, large-scale hunting raised international concern for the future of the species, but populations have rebounded after controls and quotas began to take effect. This picture shows a polar bear on an ice floe north of Svalbard, Norway, feeding on a bearded seal. Southern Elephant Seal Photo: Serge Ouachée Close-up of a juvenile Southern Elephant Seal (Mirounga leonina), showing face and mouth detail. This species of elephant seal is not only the most massive pinniped, but also the largest member of the order Carnivora living today. It is found throughout the subantarctic region. Scientific classification Kingdom→ Animalia   Phylum→ Chordata   Subphylum→ Vertebrata   Superclass→ Tetrapoda   (unranked)→ Amniota   Class→ Mammalia Subclasses and Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria * Member of a haplogroup and not any of its subclades. † Taxon is extinct. Topics Subcategories Category puzzle Select [►] to view subcategories Mammals Mammals by adaptation Mammals by classification Mammals by year of formal description Mammals by location Extinct mammals Individual mammals Lists of mammals Mammal anatomy Mammal behavior Mammal common names Mammal conservation Mammal ecology Evolution of mammals Mammal genetics Mammal health Mammalian hormones Mammals and humans Mammal images Mammal redirects Milk Mammal pest control Reproduction in mammals Songs about mammals Mammal taxa Ungulates Mammal stubs Quality content Featured articles Alcathoe bat Alpine ibex Ambondro mahabo Ambulocetus Baleen whale Bat Beaver Bharattherium Blue whale Bluebuck Bobcat Camas pocket gopher Canada lynx Catopsbaatar Columbian mammoth Cougar Cryptoprocta spelea Dermotherium Dire wolf Durrell's vontsira Elephant Elk Escalera's bat European hare Evolution of lemurs Ferugliotheriidae Ferugliotherium Flocke Fossa (animal) Giant anteater Giant eland Giant otter Giraffe Golden jackal Hartebeest Hippopotamus Homo antecessor Horseshoe bat Humpback whale Impala Jaguar Javan rhinoceros Knut (polar bear) Koala Lavanify Lion Livyatan Marcus Ward Lyon Jr. Meerkat Manor Meerkat Manor: The Story Begins Megabat Miniopterus aelleni Miniopterus griveaudi North Ronaldsay sheep Orca Paraceratherium Pennatomys Pinniped Pipistrellus raceyi Platypus Plesiorycteropus Polar bear Primate Pygmy hippopotamus Quagga Raccoon Red panda Right whale Rodent Sea mink Sea otter Sheep Short-beaked echidna Smilodon South Asian river dolphin Springbok Steller's sea cow Sumatran rhinoceros Tammar wallaby Tasmanian devil Taxonomy of lemurs Thylacine Tiger Transandinomys Triaenops menamena Wolf Woolly mammoth Zebra Featured lists List of cetaceans List of mammals of Florida List of afrosoricids List of artiodactyls List of bovids List of canids List of carnivorans List of cercopithecoids List of cervids List of cingulates List of crocidurines List of dasyuromorphs List of didelphimorphs List of diprotodonts List of erinaceids List of eulipotyphlans List of felids List of fruit bats List of herpestids List of hipposiderids List of hominoids List of lagomorphs List of leporids List of lorisoids List of macropodiformes List of macroscelids List of mammals of Korea List of mephitids List of miniopterids List of molossids List of mustelids List of myosoricines List of ochotonids List of peramelemorphs List of perissodactyls List of phalangeriformes List of pilosans List of pinnipeds List of platyrrhines List of primates List of procyonids List of rhinolophids List of scandentians List of soricines List of suines List of talpids List of tarsiiformes List of ursids List of vespertilionines List of viverrids Featured topics Lagomorphs Mesozoic mammals of Madagascar Oryzomys Primates Transandinomys Voalavo Featured pictures File:07. Camel Profile, near Silverton, NSW, 07.07.2007.jpg File:094 Wild female Alpine Ibex at Creux du Van Photo by Giles Laurent.jpg File:2010-kodiak-bear-1.jpg File:2012-bb-jackal-1.jpg File:Aepyceros melampus petersi female 8014.jpg File:African Bush Elephant.jpg File:African elephant warning raised trunk.jpg File:Albino Macropus rufogriseus rufogriseus.jpg File:Antarctic Sound-2016-Brown Bluff–Leopard seal (Hydrurga leptonyx) 04.jpg File:Antarctic Sound-2016-Brown Bluff–Leopard seal (Hydrurga leptonyx) 05.jpg File:Antidorcas marsupialis 2.jpg File:Bengal tiger (Panthera tigris tigris) female 3 crop.jpg File:Bison skull pile edit.jpg File:Blue Wildebeest, Ngorongoro.jpg File:Bos grunniens at Letdar on Annapurna Circuit.jpg File:Bos grunniens at Yundrok Yumtso Lake.jpg File:BrownSpiderMonkey (edit2).jpg File:CH cow 2.jpg File:California sea lion in La Jolla (70568).jpg File:Cattle tyrant (Machetornis rixosa) on Capybara.jpg File:Cervus canadensis nannodes at Tomales Point.jpg File:Charolais cattle, Sierra Nevada, Venezuela.jpg File:Cheetahs on the Edge (Director's Cut).ogv File:Chipmunk with stuffed cheeks in Prospect Park (05980).jpg File:Choloepus hoffmanni (Puerto Viejo, CR) crop.jpg File:Common seal (Phoca vitulina) 2.jpg File:Cow giving birth, in Laos (step by step).jpg File:Cynomys ludovicianus GNP 21.jpg File:Drymoreomys albimaculatus 002.jpg File:Endangered arctic - starving polar bear.jpg File:Eurasian brown bear (Ursus arctos arctos) female 1.jpg File:European bison (Bison bonasus) male Białowieza.jpg File:Felis silvestris silvestris.jpg File:Female impala.jpg File:Fighting impalas edit2.jpg File:Five-striped palm squirrel (Funambulus pennantii).jpg File:Galerella sanguinea Zoo Praha 2011-2.jpg File:Gemsbok (Oryx gazella) male.jpg File:Giraffa camelopardalis head (Profil).jpg File:Giraffe Mikumi National Park.jpg File:Haeckel Chiroptera.jpg File:Hippo pod edit.jpg File:Horse anatomy.svg File:Humpbackwhale singing.webm File:Impala mutualim with birds wide.jpg File:Indian rhinoceros (Rhinoceros unicornis) 4.jpg File:Jaguar (Panthera onca palustris) male Three Brothers River 2.jpg File:Koala climbing tree.jpg File:Lama glama Laguna Colorada 2.jpg File:Lion (Panthera leo) male 6y.jpg File:LutraCanadensis fullres.jpg File:MC Drei-Finger-Faultier.jpg File:Macrocranion tupaiodon 01.jpg File:Macropus rufogriseus rufogriseus Bruny.jpg File:Marmota monax UL 04.jpg File:Mother and baby sperm whale.jpg File:Mud Cow Racing - Pacu Jawi - West Sumatra, Indonesia.jpg File:Nilgai (Boselaphus tragocamelus) male.jpg File:Oryctolagus cuniculus Tasmania 2.jpg File:Panthera tigris tigris Tidoba 20150306.jpg File:Perameles gunni.jpg File:Plains Zebra Equus quagga.jpg File:Red Panda (24986761703).jpg File:Red Panda.JPG File:Red-tailed squirrel (Sciurus granatensis chrysuros) male Caldas.jpg File:Roan antelope (Hippotragus equinus koba).jpg File:Rock hyrax (Procavia capensis) 2.jpg File:Sable antelope (Hippotragus niger) adult male.jpg File:Sea otter nursing02.jpg File:Sidney Hall - Urania's Mirror - Ursa Major.jpg File:Sonoma chipmunk at Samuel P. Taylor State Park.jpg File:South-western black rhinoceros (Diceros bicornis occidentalis) female.jpg File:Spotted hyena (Crocuta crocuta).jpg File:The Monarch of the Glen, Edwin Landseer, 1851.png File:Thylogale billardierii.jpg File:Topi (Damaliscus lunatus jimela) female.jpg File:Tragelaphus strepsiceros ♂ (head).jpg File:Ugandan kobs (Kobus kob thomasi) female and calf.jpg File:Vombatus ursinus -Maria Island National Park.jpg File:Xerus inauris.jpg File:Zebra portrait.jpg Good articles Acrophyseter Addax African wild dog Alpine pika Amami rabbit Andrewsarchus Animal echolocation Anoplotherium Apeomyoides Ardipithecus ramidus Argentodites Arktocara Asian elephant Aurochs Australopithecus deyiremeda Australopithecus garhi Australopithecus sediba Azilestes Banteng Bare-tailed woolly opossum Bat virome Bay duiker Bear Beaver drop Big brown bat Billy (pygmy hippo) Binky (polar bear) Black-footed cat Black-tailed jackrabbit Black wildebeest Blackbuck Blue duiker Blue wildebeest Bohor reedbuck Boreray sheep Bottlenose dolphin Bovidae Bramble Cay melomys Brown bear Brygmophyseter California sea lion Campbell's dwarf hamster Canidae Capybara Castorocauda Cat Cattle Cheetah Chororapithecus Christmas Island flying fox Cinnamon red bat Clouded leopard Common eland Common vampire bat Coyote Pigs in culture Dacrytherium Dark long-tongued bat Dibatag Dichodon (mammal) Dimetrodon Diplobune Diprotodon Doedicurus Domestic rabbit Domestication of the sheep Dromedary Dryopithecus Dugong Dusky dolphin Dwarf dog-faced bat Dwarf sperm whale Egyptian fruit bat Elephant endotheliotropic herpesvirus Enhydriodon Equus (genus) Ethiopian hare Ethiopian highland hare European polecat Evolution of cetaceans False killer whale Ferret-legging Fin whale Fisher (animal) Fishing cat Flea Forrest's pika Four-horned antelope Fraternal fruit-eating bat Galulatherium Geoffroy's spider monkey Giant golden-crowned flying fox Giant panda Gigantopithecus Glover's pika Glyptodon Glyptotherium Goat Great flying fox Grévy's zebra Guano Hammer-headed bat Herdwick Herto Man Heuglin's gazelle Hipposideros besaoka Homo rudolfensis Homo ergaster Homo habilis Homo heidelbergensis Honduran white bat Horse Human Idaho pocket gopher Indian flying fox Indian rhinoceros Inyo shrew Isalo serotine Jacob sheep Jaguarundi Janjucetus Japanese serow Josephoartigasia Jungle cat Kenyanthropus Kitti's hog-nosed bat Klipspringer Kogia pusilla LACM 149371 Lagrivea Laomaki Large Black Least weasel Leopard Lesser kudu Little brown bat Malagasy hippopotamus Mammal Manavi long-fingered bat Marine mammal Marsh shrew Meerkat Megaherbivore Mesozoic mammals of Madagascar Microgale macpheei Miniopterus brachytragos Miniopterus mahafaliensis Miniopterus tao Miniopterus zapfei Mixtotherium Monk seal Mountain nyala Moupin pika Muskrat Nakalipithecus Narwhal Natal red rock hare Nilgai Nyala Ocelot Ocepeia Okapi Orcinus citoniensis Oribi Ortotherium Palaeotherium Panthera onca mesembrina Paranthropus Paranthropus aethiopicus Paranthropus boisei Paranthropus robustus Paratheria (mammals) Pig Pilot whale Plains zebra Porpoise Pteropus Pubal Pudu Pygmy three-toed sloth Quoll Rabbit Red fox Reigomys Rhinogradentia Rice's whale River dolphin Royal antelope Saadanius Sei whale Serval Setirostris Shetland sheep Sirenia Sitatunga Six-banded armadillo Smith's red rock hare Snow leopard Spectral bat Spotted hyena Stellaluna Stotting Sun bear Swift fox Tamaraw Thalassocnus Tiger quoll Trapalcotherium Triaenops goodmani Tricolored bat Tupaia miocenica Turkestan red pika UA 8699 Veratalpa Vietnam mouse-deer Walrus Waterbuck Whale White-lipped peccary Wildebeest William Windsor (goat) Winter white dwarf hamster Xiphodon Yarkand hare Yellow-bellied marmot Yunnan hare Zygophyseter Pallas's cat Sand cat Asiatic cheetah Scimitar oryx WikiProjects Biology Tree of Life Plants Arthropods Cephalopods Gastropods Fishes Amphibians and Reptiles Birds Mammals WikiProject Mammals Bats task force WikiProject Dogs WikiProject Dog breeds WikiProject Rodents WikiProject Cats WikiProject Equine WikiProject Horse breeds WikiProject Cetaceans WikiProject Primates WikiProject Monotremes and Marsupials Viruses A complete list of scientific WikiProjects can be found here. See also Wikispecies, a Wikimedia project dedicated to classification of biological species. Things to do Here are some tasks awaiting attention: Article requests : Missing mammal species articles – Create a new article Cleanup : Cleanup listing for WikiProject Mammals – Functional list of mammal articles that need improvements Photo : Mammal articles without images – Upload and/or add images to articles Stubs : Expand Stub-Class mammal articles External media Wilson & Reeders Mammal Species of the World – from Bucknell University Mammal Species of the World – from National Museum of Natural History, Smithsonian Institution Associated Wikimedia The following Wikimedia Foundation sister projects provide more on this subject: Commons Free media repository Wikibooks Free textbooks and manuals Wikidata Free knowledge base Wikinews Free-content news Wikiquote Collection of quotations Wikisource Free-content library Wikispecies Directory of species Wikiversity Free learning tools Wiktionary Dictionary and thesaurus Discover Wikipedia using portals List of all portals The arts portal Biography portal Current events portal Geography portal History portal Mathematics portal Science portal Society portal Technology portal Random portal WikiProject Portals