Portal:Mammals

The Mammals portal

A mammal (from Latin mamma 'breast') is a vertebrate animal of the class Mammalia (/məˈmeɪli.ə/). Mammals are characterised 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 6,640 extant species of mammals have been described and divided into 27 orders. The study of mammals is called mammalogy.

The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (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 vocalise in several ways, including the production of ultrasound, scent marking, alarm signals, singing, echolocation; and, in the case of humans, complex language. Mammals can organise 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 civilisations. 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...)

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The elk, or wapiti (Cervus canadensis), is the second largest species of deer in the world and one of the largest mammals in North America and eastern Asia. In the deer family (Cervidae), only the moose, Alces alces (called an "elk" in Europe), is larger. Wapiti are almost identical to red deer found in Europe, of which they were long believed to be a subspecies; they have recently been determined to be a distinct species based on DNA evidence. Elk range in forest and forest-edge habitat, feeding on grasses, plants, leaves and bark. Although native to North America and eastern Asia, they have adapted well to countries where they have been introduced, including New Zealand and Argentina. Their high level of adaptability poses a threat to endemic species and ecosystems where they have been introduced. Male elk have large antlers which are shed each year. Males engage in ritualized mating behaviors during the rut, including posturing, antler wrestling and bugling, a loud series of screams which establishes dominance over other males and attracts females. The bugle call is one of the most distinctive calls in nature. Elk are susceptible to a number of infectious diseases, some of which can be transmitted to livestock. Efforts to eliminate infectious diseases from elk populations, largely through vaccination, have had mixed success. Some cultures revere the elk as a spiritual force. In parts of Asia, antlers and their velvet are used in traditional medicines. Elk are hunted as a game species; the meat is leaner and higher in protein than beef or chicken.

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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?

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Image 1
Meerkat
Photo: Fir0002
The meerkat (Suricata suricatta) is a small member of the mongoose family native to the Kalahari Desert of southern Africa. They are social animals, living underground in groups of 20 to 50 members. Although the name means "lake cat" in Dutch, meerkats are not cats, nor are they attracted to lakes.
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Image 2
Humpback Whale
Photo credit: Georgia Evelyn Stants
Off the coast of Juneau, Alaska, a group of 15 Humpback Whales works in tandem to catch herring using the bubble net feeding technique, in which they exhale through their blowholes, creating a ring of bubbles up to 30 m (100 ft) in diameter. The whales then suddenly swim upwards through the bubble net swallowing thousands of fish in each gulp.
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Image 3
Sheep
Photograph: Keith Weller/Agricultural Research Service
Sheep are quadrupedal ruminants, typically kept as livestock. Although the name "sheep" applies to many species in the genus Ovis, in everyday usage it generally refers to Ovis aries. One of the first animals to be domesticated, sheep are likely descended from the wild mouflon of Europe and Asia. They are raised for their fleece, meat, and milk.
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Image 4
Hoffmann's two-toed sloth
Photograph: Geoff Gallice
Hoffmann's two-toed sloth (Choloepus hoffmanni) is a species of sloth from Central and South America named for the German naturalist Karl Hoffmann. This solitary, largely nocturnal and arboreal animal, is found in mature and secondary rainforests and deciduous forests. Adults range from 54 to 72 cm (21 to 28 in) in head-body length, and weigh from 2.1 to 9 kg (4.6 to 19.8 lb). Females are larger on average than males, although with considerable overlap in size.
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Image 5
Lion
Photo credit: Luca Galuzzi
Male lion (Panthera leo) and cub eating a Cape buffalo in Northern Sabi Sand, South Africa. Lions are true predators who can require an average of up to seven kilograms (15 lbs) of meat daily to survive. Large mammals comprise an important part of a lion's diet.
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Image 6
Japanese Squirrel
Photo credit: Ma2bara
The Japanese Squirrel (Sciurus lis) is a species of rodent in the Sciuridae family. It is endemic to Japan.
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Image 7
Steenbok
Photograph: Yathin S Krishnappa
The steenbok (Raphicerus campestris) is a species of small antelope, generally standing 45–60 centimeters (16–24 inches) at the shoulder, commonly found in Africa. They live in a variety of habitats, from semi-desert to open woodland and thickets, and feed on low-level vegetation and roots. These common animals are typically solitary, except during mating season.
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Image 8
Australian feral camel
Photo credit: John O'Neill
A dromedary or one-humped camel (Camelus dromedarius) in the Australian Outback. Estimated populations of Australian feral camels are in the hundreds of thousands, and this is now the world's only population of dromedaries exhibiting wild behaviour. Thousands of camels were imported into Australia between 1840 and 1907 to open up the arid areas of central and western Australia. They were used for riding, and as draught and pack animals for exploration and construction of rail and telegraph lines; they were also used to supply goods to remote mines and settlements. Their impact on the environment is not as bad as that of other introduced pests in Australia. They prefer to eat trees and plants that local wildlife dislike; only 2% of their diet is grass.
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Image 9
Eastern gray squirrel
Photograph credit: Tom Friedel
The eastern gray squirrel (Sciurus carolinensis) is a tree squirrel in the genus Sciurus, native to the eastern and midwestern United States, as well as to the southerly portions of the eastern provinces of Canada. A prolific and adaptable species, it has been introduced to and thrives in several regions of the western United States; it is also an invasive species in Britain, where it has spread across the country and largely displaced the native Eurasian red squirrel. The head and body can measure from 23 to 30 cm (9.1 to 11.8 in) and the tail from 19 to 25 cm (7.5 to 9.8 in) in length; its adult weight is between 400 and 600 g (14 and 21 oz). Like many members of the family Sciuridae, the eastern gray squirrel is a scatter-hoarder; it hoards food in numerous small caches for later recovery. In the United Kingdom and Canada, the species is simply referred to as the "grey squirrel".

This picture, taken in 2010, shows an eastern gray squirrel in Florida.
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Image 10
Lioness
Photo credit: Cody Pope
A lioness in Ishasha Southern sector of Queen Elizabeth National Park, Uganda. Ishasha lions are famed for tree climbing, a trait only shared with lions in the Lake Manyara region. They often spend the hottest parts of the day in the large fig trees found throughout the area. It is still unclear why so few lions exhibit this behavior.
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Image 11
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.
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Image 12
Lion
Photo credit: yaaaay
A male lion (Panthera leo) lying down in Namibia. One of the four "big cats" in the genus Panthera, the lion is the second largest cat, after the tiger. Males weigh between 150-250 kg (330-550 lb), and are easily recognizable by their manes. Though they were once found throughout much of Africa, Asia and Europe, lions presently exist in the wild only in Africa and India.
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Image 13
Impala
Photograph: Muhammad Mahdi Karim
A portrait of a male impala, showing its horns. Horns consist of bone cores surrounded by a covering of keratin and other proteins, and are often curved or spiral in shape. Most horned animal species have one pair, though some may have more.
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Image 14
Cheetah
Photo: Muhammad Mahdi Karim
A close-up view of a cheetah (Acinonyx jubatus) cub. Unlike some other cats, the cheetah is born with its characteristic spots, as well as a downy underlying fur on their necks extending to mid-back, which gives the cub the appearance of the honey badger, to scare away potential aggressors. Despite this, up to 90% of cheetah cubs are killed by predators in the early weeks of life. Healthy adult cheetahs have few predators because of their speed.
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Image 15
Impala
Photo: Alchemist-hp
Several female black-faced impala drinking at a waterhole. Impalas are sexually dimorphic. Females can weigh 10 to 25 kilograms (22 to 55 lb) less than males and do not have horns.
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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.

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