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 Pygmy Hippopotamus (Choeropsis liberiensis) is a large mammal native to the forests and swamps of western Africa (the scientific species classification means "of Liberia", as this is where the vast majority lives). The pygmy hippo is reclusive and nocturnal. It is one of only two extant species in the hippopotamidae family, the other being its much larger cousin the common hippopotamus. The pygmy hippopotamus displays many terrestrial adaptations, but like its larger cousin, it is semi-aquatic and relies on proximity to water to keep its skin moisturized and its body temperature cool. Behaviors such as mating and birth may occur in water or on land. The pygmy hippo is herbivorous, feeding on whatever ferns, broad-leaved plants, grasses and fruits it finds in the forests. A rare nocturnal forest creature, the pygmy hippopotamus is a difficult animal to study in the wild; it also lives primarily in countries with a great degree of civil strife. Pygmy hippos lead mostly solitary lives; they are sometimes seen in pairs or threesomes, but never large pods like the common hippopotamus. Unlike the common hippopotamus, they are not known to be territorial.

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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
Zebra
Photo: Muhammad Mahdi Karim
A portrait of a Plains Zebra (Equus quagga), the most common and widespread species of zebra. The unique stripes and behaviors of zebras make these among the animals most familiar to people. They can be found in a variety of habitats throughout Sub-Saharan Africa. The name "zebra" comes from the Old Portuguese word zevra which means "wild ass". Zebra stripes are typically vertical on the head, neck, forequarters, and main body, with horizontal stripes at the rear and on the legs of the animal. It was previously believed that zebras were white animals with black stripes. Embryological evidence, however, shows that the animal's background color is black and the white stripes are additions.
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Image 2
Javan slow loris
Photograph credit: Aprisonsan
The Javan slow loris (Nycticebus javanicus) is a species of primate native to western and central portions of the Indonesian island of Java. It is arboreal, feeding on fruit, gum, eggs, lizards, and the seeds of the cocoa tree. Weighing up to 680 g (24 oz), this small nocturnal mammal sleeps in the open on branches during the day and is easily poached for the exotic-pet trade. Populations are declining, and the animal is listed by the International Union for Conservation of Nature as a critically endangered species and included in a list of the world's 25 most endangered primates.
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Image 3
Tamias rufus
Photo credit: Mdf
The Hopi Chipmunk (Tamias rufus) is a chipmunk found in Colorado, Utah and New Mexico, in the Southwestern United States. Chipmunks are small squirrel-like rodents, native to North America except for one species in northeastern Asia. Though they are commonly depicted with their paws up to the mouth, eating peanuts, or with their cheeks bulging out on either side, chipmunks are actually omnivorous.
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Image 4
Virginia Opossum
Photo credit: Cody Pope
The Virginia Opossum (Didelphis virginiana) is the only marsupial found in North America. A solitary and nocturnal animal about the size of a domestic cat, it is a successful opportunist and is found throughout North America from coast to coast (introduced to California in 1910), and from Central America and Mexico to southern Canada.
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Image 5
Yak
Photograph: travelwayoflife
A yak at Letdar on the Annapurna Circuit in the Annapurna mountain range of central Nepal. Mostly domesticated, these long-haired bovids are found throughout the Himalayan region of south Central Asia, the Tibetan Plateau and as far north as Mongolia and Russia.
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Image 6
Tabby cat
Photo: Joaquim Alves Gaspar
A tabby is any cat that has a distinctive coat that features stripes, dots, lines or swirling patterns, usually together with a mark resembling an "M" on its forehead. Tabbies are not a cat breed, but a coat pattern found in many breeds of cat, as well as among the general mixed-breed population. The tabby pattern may be related to the coloration of the domestic cat's direct ancestor, the African Wildcat, which (along with the European Wildcat and Asiatic Wildcat) has a similar coloration. There are four genetically distinct tabby patterns: mackerel (shown here), classic, spotted, and ticked.
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Image 7
Tadoba Andhari Tiger Reserve
Photograph credit: Stephenekka
The Tadoba Andhari Tiger Reserve is the largest national park in the state of Maharashtra in central India. Most of the reserve consists of natural dry deciduous forests, however parts have been cleared for firewood or grazing land. Besides tigers, there are Indian leopards, sloth bears, gaurs, nilgais, dholes, striped hyenas, small Indian civets, jungle cats, sambars, muntjacs, chitals, chousinghas and honey badgers. There are also villages in the reserve, and although cattle grazing is not allowed in the core zone, some livestock inevitably stray inside. In 2013, at least four people and thirty to fifty cattle were killed by leopards, tigers and sloth bears. This picture shows a Bengal tigress named Maya photographed in the reserve.
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Image 8
Jaguar
Photo credit: Pascal Blachier
The jaguar (Panthera onca), shown here at Edinburgh Zoo, is a New World mammal of the Felidae family and one of four "big cats". The jaguar is the third-largest feline after the tiger and the lion, and on average the largest and most powerful feline in the Western Hemisphere.
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Image 9
Brown Spider Monkey
Photo credit: Tom Friedel
The Brown Spider Monkey is a critically endangered New World monkey native to Colombia and Venezuela. The blue eyes on this individual are uncommon among the species.
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Image 10
Hereford calf
Photo credit: John O'Neill
An unmarked Hereford calf. Hereford cattle (Bos taurus) are a widely used breed in temperate areas, mainly for beef production. Originally from Herefordshire, England, they are found in the temperate parts of Australia, the Southwestern US, Western Canada, Argentina, Uruguay and New Zealand.
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Image 11
Koala
Photo: JJ Harrison
A female koala (Phascolarctos cinereus), an arboreal herbivorous marsupial native to coastal regions of eastern and southern Australia. The word "koala" comes from the Dharuk word gula. English-speaking settlers from the late 18th century first called it "koala bear" due to its similarity in appearance to bears, although they are not at all related. Instead, its closest living relative is the wombat.
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Image 12
Southern Elephant Seal
Photo: Serge Ouachée
Close-up of a juvenile Southern Elephant Seal (Mirounga leonina), showing face and mouth detail. This species of elephant seal is not only the most massive pinniped, but also the largest member of the order Carnivora living today. It is found throughout the subantarctic region.
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Image 13
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 14
Eastern Gray Squirrel
Photo credit: Diliff
An Eastern Gray Squirrel (Sciurus carolinensis) eating a nut in St. James's Park, London. Although native to eastern North America, the species has been introduced into a variety of locations. In England, gray squirrels have mostly replaced native Red Squirrels and have no natural predators, which has added to their rapid population growth and has led to the species being classed as a pest.
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Image 15
European Hedgehog
Photo: Hrald
The European Hedgehog (Erinaceus europaeus) is a hedgehog species native to western and northern Europe. Adults are 20–30 cm (7.9–11.8 in) in length, weighing from 600 to 1,200 g (21 to 42 oz), depending on the season, with males slightly larger than females. It is nocturnal, and if alarmed will roll itself into a ball, protecting itself against potential predators with its spines.
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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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