Portal:Mammals

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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 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?

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Image 1
Greater kudu
Photograph credit: Hans Hillewaert
The greater kudu (Tragelaphus strepsiceros) is a species of woodland antelope in the genus Tragelaphus found throughout eastern and southern Africa. Despite occupying widespread territory, they are sparsely populated in most areas due to declining habitat, deforestation and poaching. The greater kudu is one of two species commonly known as kudu, the other being the lesser kudu, T. imberbis. Greater kudus have a narrow body with long legs, and their coats can range from brown or bluish grey to reddish brown. They possess between four and twelve vertical white stripes along their torso. The head tends to be darker in colour than the rest of the body, and exhibits a small white chevron running between the eyes. The helical horns of adult males grow as the animal ages, reaching
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2+1⁄2 rotations at about 6 years old.

This picture shows a greater kudu bull photographed near Groot Okevi in Etosha National Park, Namibia. Bulls weigh 190–270 kg (420–600 lb), up to a maximum of 315 kg (690 lb), and stand up to 160 cm (63 in) tall at the shoulder.
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Image 2
Pot-bellied pig
Photo credit: Joaquim Alves Gaspar
Two pot-bellied pigs sleeping. This breed of domestic pig belongs to the same species as the Wild Boar and the common farm pig (Sus domestica), and originated in Vietnam. Most adult pot-bellied pigs are about the size of a medium- or large-breed dog, though their bodies are denser at a weight of 60 to 300 pounds (27 to 136 kg).
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Image 3
A yellow-headed caracara perched on a capybara
Photograph: Charles J. Sharp
A yellow-headed caracara (Milvago chimachima) on the back of a capybara (Hydrochoeris hydrochaeris) in the Pantanal in the State of Mato Grosso do Sul, Brazil. Caracaras are a type of falcon that typically scavenge for their food, while capybaras are the largest rodents in the world.
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Image 4
Giraffe
Photo: Muhammad Mahdi Karim
A giraffe extending its tongue to feed. Its tongue, lips and palate are tough enough to deal with sharp thorns in trees. Giraffes prefer trees of the genera Acacia, Commiphora and Terminalia. A giraffe requires less food than typical grazing animals, typically consuming 65 pounds (29 kg) of leaves and twigs daily, because the foliage it eats has more concentrated nutrition and it has a more efficient digestive system.
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Image 5
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.
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Image 6
Zootomical terms of location
Photo credit: Jonathan Merritt
Zootomical terms of location overlap considerably with terms used in human anatomy. In animals, the head end is called the "cranial end" and the tail end is the "caudal end". The side of the body normally oriented upwards is the "dorsal" side; the opposite side, typically the one closest to the ground when walking on all legs, swimming or flying, is the "ventral" side.
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Image 7
Northern Elephant Seals
Photo credit: Helen Filatova
A group of female Northern Elephant Seals (Mirounga angustirostris) moulting on a beach near San Simeon, California. In the summer, elephant seals undergo a catastrophic moult, lasting about one month, during which they lose much of their fur and skin. They spend this time on beaches to preserve body heat, while they wait for the new fur to grow.
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Image 8
Springbok
Photo: Hans Hillewaert
The springbok is a medium-sized brown and white gazelle native to southwestern Africa. It stands about 70 to 90 cm (28 to 35 in) high and is known for its jumping ability, being able to leap 4 m (13 ft) in the air and over a distance of 15 m (49 ft). It is also a fast runner, capable of reaching speeds up to 96 km/h (60 mph). The springbok is the national animal of South Africa.
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Image 9
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 10
Lesser short-nosed fruit bat
Photo: Anton Croos
A newborn lesser short-nosed fruit bat (Cynopterus brachyotis) clinging upon a human finger. A species of megabat within the family Pteropodidae, it is a small bat that lives in South and Southeast Asia. Adults weigh between 21 and 32 grams (0.74 and 1.13 oz).
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Image 11
Common wombat
Photo: JJ Harrison
The common wombat (Vombatus ursinus) is one of three species of wombat. It is native to south-eastern mainland Australia and Tasmania, and grows to an average of 98 cm (39 in) long and a weight of 26 kg (57 lb). It is solitary and lives in an underground burrow.
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Image 12
Yak
Photograph: Dennis Jarvis
A domesticated yak at Yamdrok Lake in Tibet. The animals are important to Tibetan culture, and have been kept for thousands of years. The yaks are a method of transportation and serve as beasts of burden. Their feces are a source of fuel, and their milk can be used for butter, which is then made into sculptures or consumed.
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Image 13
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 14
Siberian tiger
Photo: Dave Pape
A female Siberian tiger (Panthera tigris altaica), a subspecies of tiger native to Central Asia, and her cub. The Siberian tiger is the largest of the extant tiger subspecies as well as the largest felid, attaining 320 kg (710 lb) in an exceptional specimen. Considered an endangered subspecies, the wild population is down to several hundred individuals and is limited to eastern Siberia.
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Image 15
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.
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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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