Jump to content

Portal:Mammals

From Wikipedia, the free encyclopedia
(Redirected from Portal:Mammal)

The Mammals portal

A mammal (from Latin mamma 'breast') is a vertebrate animal of the class Mammalia (/məˈmli.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

Fin Whale
The Fin Whale (Balaenoptera physalus), also called the Finback Whale or Razorback or Common Rorqual, is a marine mammal belonging to the suborder of baleen whales. It is the second largest whale and the second largest living animal after the Blue Whale, growing to nearly 27 meters (88 ft) long. Long and slender, the Fin Whale's body is brownish-grey with a paler underside. There are at least two distinct subspecies: the Northern Fin Whale of the North Atlantic, and the larger Antarctic Fin Whale of the Southern Ocean. It is found in all the world's major oceans, from polar to tropical waters. It is absent only from waters close to the ice pack at both the north and south poles and relatively small areas of water away from the open ocean. The highest population density occurs in temperate and cool waters. Its food consists of small schooling fish, squid and crustaceans including mysids and krill.

Did you know?

  • ....that Caracal (pictured) is very powerful for its size and has even been known to bring down a full grown adult Gazelle?
  • ...that Snuppy the Afghan Hound is the world's first cloned dog?
  • ...the male narwhal's tusk can be up to 3 metres in length and weigh up to 10 kilograms?
  • ...the Voyager Golden Record carried into space whale songs, among other sounds?
  • ...that 217 Dalmatians were used in the filming of 101 Dalmatians?
  • ...that Scarlett the cat is a former stray cat whose efforts to save her kittens from a fire, at serious harm to herself, attracted worldwide media attention and has been related in a number of nonfiction books?
  • ...that Dr. Johnson's cat Hodge has his own statue in Gough Square, London?

Selected images

Scientific classification

KingdomAnimalia   PhylumChordata   SubphylumVertebrata   SuperclassTetrapoda   (unranked)Amniota   ClassMammalia



Topics

Subcategories

Category puzzle
Category puzzle
Select [►] to view subcategories

Quality content

Good articles

Things to do


Here are some tasks awaiting attention:

External media

Associated Wikimedia

The following Wikimedia Foundation sister projects provide more on this subject:

Discover Wikipedia using portals