Portal:Mammals

From Wikipedia, the free encyclopedia
  (Redirected from Portal:Mammal)
Jump to: navigation, search

Mammals

Echidna - melbourne zoo.jpg

Mammals (class Mammalia) are vertebrate animals characterized by the presence of sweat glands, including milk producing sweat glands, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex region in the brain. Mammals, other than the monotremes, give birth to live young instead of laying eggs. They also possess specialized teeth and use a placenta in the ontogeny. The mammalian brain regulates endothermic and circulatory systems, including a four-chambered heart. Mammals encompass approximately 5,400 species, ranging in size from the Bumblebee Bat, (30-40mm), to the Blue Whale, (33,000mm), distributed in about 1,200 genera, 153 families, and 29 orders, though this varies by classification scheme.

Most mammals belong to the placental group. The four largest orders within the placental mammals are Rodentia (mice, rats, and other small, gnawing mammals), Chiroptera (bats), Carnivora (dogs, cats, bears, and other mammals that primarily eat meat), and Cetartiodactyla (including numerous herbivore species, such as deer, sheep, goats, and buffalos, plus whales).

Phylogenetically, Mammalia is defined as all descendants of the most recent common ancestor of monotremes (e.g., echidnas and platypuses) and therian mammals (marsupials and placentals). This means that some extinct groups of "mammals" are not members of the crown group Mammalia, even though most of them have all the characteristics that traditionally would have classified them as mammals. These "mammals" are now usually placed in the unranked clade Mammaliaformes.

The mammalian line of descent diverged from the sauropsid line at the end of the Carboniferous period. The sauropsids would evolve into modern-day reptiles and birds, while the synapsid branch led to mammals. The first true mammals appeared in the Jurassic period. Modern mammalian orders appeared in the Palaeocene and Eocene epochs of the Palaeogene period.

Nuvola filesystems www.png Mammals ...

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?

Tamias striatus2.jpg

Selected picture

Otters
Credit: Dmitry Azovtsev

The Otter (Lontra canadensis) is a North American member of the Mustelidae or weasel family. It is also known as the North American River Otter. It is a common animal in North American waterways. Its numbers have significantly dropped since Europeans came to colonize the Americas

Scientific classification

KingdomAnimalia   PhylumChordata   SubphylumVertebrata   SuperclassTetrapoda   (unranked)Amniota   ClassMammalia


Topics

Quality content

Featured article Babakotia Featured article Blue whale Featured article Beagle Featured article Bobcat Featured article Cougar Featured article Domestic sheep Featured article Elk Featured article Eremoryzomys Featured article Fin whale Featured article Giant Otter Featured article Gray Mouse Lemur Featured article Guinea pig Featured article Hippopotamus Featured article Homo floresiensis Featured article Humpback whale Featured article Island Fox Featured article Jaguar Featured article Javan Rhinoceros Featured article Killer whale Featured article Knut (polar bear) Featured article Lemur Featured article Lion Featured list List of lemur species Featured article Lundomys Featured article Marsh rice rat Featured article Meerkat Manor Featured article Meerkat Manor: The Story Begins Featured article Mindomys Featured article Noronhomys Featured article Oryzomys Featured article Oryzomys couesi Featured article Oryzomys dimidiatus Featured article Oryzomys gorgasi Featured article Platypus Featured article Primate Featured article Pseudoryzomys Featured article Pygmy Hippopotamus Featured article Raccoon Featured article Right whale Featured article Ring-tailed Lemur Featured article Ruffed lemur Featured article Sea otter Featured article Sei whale Featured article Short-beaked Echidna Featured article Sumatran Rhinoceros Featured article Tasmanian Devil Featured article Thylacine Featured article Transandinomys bolivaris Featured article Transandinomys talamancae Featured article Triaenops menamena Featured article Whale song


?Oryzomys pliocaenicus Arabian horse Carletonomys Central American Squirrel Monkey Ekbletomys Fancy rat Ferret legging Fossa (animal) Geoffroy's Spider Monkey Hadropithecus Herdwick Hipposideros besaoka Kitti's Hog-nosed Bat Labrador Retriever Malagasy Hippopotamus Mantled Howler Microgale macpheei North American River Otter Oecomys sydandersoni Oryzomys peninsulae Plesiorycteropus Pudú Red Panda Sperm whale Tamaraw Triaenops goodmani UA 8699 Walrus White-headed Capuchin William Windsor (goat)

Wikimedia

Mammals on Wikinews     Mammals on Wikiquote     Mammals on Wikibooks     Mammals on Wikisource     Mammals on Wiktionary     Mammals on Wikimedia Commons Mammals on Wikispecies    
News Quotations Manuals & Texts Texts Definitions Images & Media Species directory
Mammals
Mammals
Mammals
Mammals
Mammals
Mammals
Mammals