Before the featured portal process ceased in 2017, this had been designated as a featured portal.

Portal:Mammals

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

The Mammals portal

Mammal Diversity 2011.png

Mammals are the vertebrates within the class Mammalia (/məˈmliə/ from Latin mamma "breast"), a clade of endothermic amniotes distinguished from reptiles (including birds) by the possession of a neocortex (a region of the brain), hair, three middle ear bones, and mammary glands. Females of all mammal species nurse their young with milk, secreted from the mammary glands.

Mammals include the largest animal on the planet, the blue whale. The basic body type is a terrestrial quadruped, but some mammals are adapted for life at sea, in the air, in trees, underground or on two legs. The largest group of mammals, the placentals, have a placenta, which enables the feeding of the fetus during gestation. Mammals range in size from the 30–40 mm (1.2–1.6 in) bumblebee bat to the 30-meter (98 ft) blue whale. With the exception of the five species of monotreme (egg-laying mammals), all modern mammals give birth to live young. Most mammals, including the six most species-rich orders, belong to the placental group. The largest orders are the rodents, bats and Soricomorpha (shrews and allies). The next three biggest orders, depending on the biological classification scheme used, are the Primates (apes and monkeys), the Cetartiodactyla (whales and even-toed ungulates), and the Carnivora (cats, dogs, seals, and allies).

Living mammals are divided into the Yinotheria (platypus and echidnas) and Theriiformes (all other mammals). There are around 5450 species of mammal, depending on which authority is cited. In some classifications, extant mammals are divided into two subclasses: the Prototheria, that is, the order Monotremata; and the Theria, or the infraclasses Metatheria and Eutheria. The marsupials constitute the crown group of the Metatheria, and include all living metatherians as well as many extinct ones; the placentals are the crown group of the Eutheria. While mammal classification at the family level has been relatively stable, several contending classifications regarding the higher levels—subclass, infraclass and order, especially of the marsupials—appear in contemporaneous literature. Much of the changes reflect the advances of cladistic analysis and molecular genetics. Findings from molecular genetics, for example, have prompted adopting new groups, such as the Afrotheria, and abandoning traditional groups, such as the Insectivora.

The mammals represent the only living Synapsida, which together with the Sauropsida form the Amniota clade. The early synapsid mammalian ancestors were sphenacodont pelycosaurs, a group that produced the non-mammalian Dimetrodon. At the end of the Carboniferous period, this group diverged from the sauropsid line that led to today's reptiles and birds. The line following the stem group Sphenacodontia split-off several diverse groups of non-mammalian synapsids—sometimes referred to as mammal-like reptiles—before giving rise to the proto-mammals (Therapsida) in the early Mesozoic era. The modern mammalian orders arose in the Paleogene and Neogene periods of the Cenozoic era, after the extinction of non-avian dinosaurs, and have been among the dominant terrestrial animal groups from 66 million years ago to the present.

Most mammals are intelligent, with some possessing large brains, self-awareness and tool use. Mammals can communicate and vocalize in several different ways, including the production of ultrasound, scent-marking, alarm signals, singing, and echolocation. 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.

In human culture, domesticated mammals played a major role in the Neolithic revolution, causing farming to replace hunting and gathering, and leading to a major restructuring of human societies with the first civilizations. They provided, and continue to provide, power for transport and agriculture, as well as various commodities such as meat, dairy products, wool, and leather. Mammals are hunted or raced for sport, and are used as model organisms in science. Mammals have been depicted in art since Palaeolithic times, and appear in literature, film, mythology, and religion. Defaunation of mammals is primarily driven by anthropogenic factors, such as poaching and habitat destruction, though there are efforts to combat this.

Selected article

Labrador Retriever
The Labrador Retriever (also Labrador or Lab for short), is one of several kinds of retriever, a type of gun dog. The Labrador is considered the most popular breed of dog (by registered ownership) in the world, and is by a large margin the most popular breed by registration in the United States (since 1991) the United Kingdom, It is also the most popular breed of assistance dog in the United States, Australia, and many other countries, as well as being widely used by police and other official bodies for their detection and working abilities. They are exceptionally affable, gentle, intelligent, energetic and good natured, and Labradors are generally considered good companions for people of all ages (including a high level of patience and tolerance for children, making them both excellent companions and working dogs. Although somewhat boisterous if untrained, Labrador Retrievers respond well to praise and positive attention, and are considerably "food and fun" oriented. These dogs are as well loyal and great with little children. They may be used in shows. With training, the Lab is one of the most dependable, obedient and multi-talented breeds in the world.

Did you know?

Caracal001.jpg
  • ....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

Quality content

Featured articles

Featured lists

Featured pictures

Good articles

Associated Wikimedia

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

Wikibooks
Books

Commons
Media

Wikinews 
News

Wikiquote 
Quotations

Wikisource 
Texts

Wikiversity
Learning resources

Wiktionary 
Definitions

Wikidata 
Database

Wikispecies 
Species


Retrieved from "https://en.wikipedia.org/w/index.php?title=Portal:Mammals&oldid=854553157"
This content was retrieved from Wikipedia : http://en.wikipedia.org/wiki/Portal:Mammals
This page is based on the copyrighted Wikipedia article "Portal:Mammals"; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA