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 Island Fox (Urocyon littoralis) is a small fox that is native to six of the eight Channel Islands (California). It is the smallest fox species in the United States. There are six subspecies of the fox, each unique to the island it inhabits, reflecting its evolutionary history. Other names for the Island Fox include Coast Fox, Short-Tailed Fox, Island Gray Fox, Channel Islands Fox, Channel Islands Gray Fox, California Channel Island Fox and Insular Gray Fox. The Island Fox shares the Urocyon genus with the mainland Gray Fox, the fox from which it is descended. Its small size is a result of island dwarfing, a kind of allopatric speciation. Because Island Foxes are geographically isolated they have no immunity to parasites and diseases brought in from the mainland and are especially vulnerable to those domestic dogs may carry. In addition, Golden Eagle predation and human activities devastated fox numbers on several of the Channel Islands in the 1990s. Four Island Fox subspecies were federally protected as an endangered species in 2004, and efforts to rebuild fox populations and restore the ecosystems of the Channel Islands are being undertaken.

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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
Joey
Photo credit: Geoff Shaw, University of Melbourne, Australia
A newborn joey (baby kangaroo) in its mother's pouch. Kangaroo babies are born at a very early stage of development after a gestation of 31-36 days. At this stage, only the forelimbs are somewhat developed, to allow the newborn to climb to the pouch and attach to a teat. It will not re-emerge for several months, during which time it develops fully.
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Image 2
Proboscis monkey
Photograph credit: Charles James Sharp
The proboscis monkey (Nasalis larvatus) is endemic to the island of Borneo, where it is found predominantly in coastal areas, near rivers and in swamp forests. It is perhaps the most aquatic of the primates and is a fairly good swimmer, capable of swimming underwater; apart from this, it is largely arboreal. This image is a composite of three photographs and shows a proboscis monkey jumping between trees in Labuk Bay in the Malaysian state of Sabah.
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Image 3
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 4
Social grooming
Photo: Muhammad Mahdi Karim
Two olive baboons (Papio anubis) engaged in social grooming, an activity that social animals (including humans) engage in to clean or maintain one another's body or appearance. Grooming also reinforces social structures, family links, and builds relationships. It has been best studied among primates, but insects, birds, fish, and other mammals are known to engage in it as well.
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Image 5
Culpeo
Photo: Christian Mehlführer
The culpeo (Lycalopex culpaeus, aka Andean fox/wolf) is the second-largest native canid in South America. It has grey and reddish fur, a white chin, reddish legs, and a stripe on its back that may be barely visible. The mean weight for males is 11.4 kg (25 lb), while females average 8.4 kg (19 lb).
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Image 6
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 7
Eastern Barred Bandicoot
Photo: JJ Harrison
The Eastern Barred Bandicoot (Perameles gunni) is a small, rabbit-sized marsupial native to Australia and Tasmania. It weighs less than 1 kg (2.2 lb) and has a short tail and three to four whitish bars across the rump. It is classified as Near Threatened, with one subspecies listed as Critically Endangered.
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Image 8
Boar
Photo credit: Richard Bartz
A wild boar (Sus scrofa), shown here in an animal sanctuary, the wild ancestor of the domestic pig. Boars are native across much of Central Europe, the Mediterranean Region and much of Asia. Wild boars almost always have thick, short bristly coats ranging in colour from brown through grey to black.
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Image 9
Lar gibbon
Photograph: JJ Harrison
The lar gibbon (Hylobates lar) is a primate found in South-East Asia. This endangered gibbon species is primarily a frugivore, but may also feed on leaves, flowers, and insects.

This specimen was photographed in Kaeng Krachan National Park, Phetchaburi, Thailand.
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Image 10
Olive baboon
Photo: Muhammad Mahdi Karim
The olive baboon (Papio anubis) is an Old World monkey found in 25 countries throughout Africa, making it the most widely ranging of all baboons. It is named for its coat, which, at a distance, is a shade of green-grey. At closer range, its coat is multi-colored, due to rings of yellow-brown and black on the hairs. It is omnivorous, finding nutrition in almost any environment, and able to adapt with different foraging tactics.
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Image 11
Golden-mantled Ground Squirrel
Photo credit: Eborutta
The Golden-mantled Ground Squirrel (Spermophilus lateralis) is a species of squirrel native throughout North America and can be found in a wide variety of forest habitats as well as rocky meadows, and even sagebrush flats. It can be identified by its chipmunk-like stripes and coloration, but unlike chipmunks, it lacks any facial stripes.
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Image 12
Donkey
Photograph: Lilly M
A 3-week-old donkey (Equus africanus asinus), in Kadzidłowo, Poland. A female donkey is normally pregnant for about 12 months, and usually gives birth to a single foal; twins are rare.
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Image 13
Impala
Photograph: Muhammad Mahdi Karim
A female impala (Aepyceros melampus) photographed at Mikumi National Park, Tanzania. These medium-sized African antelopes inhabit savanna grasslands and woodlands close to water sources, feeding on grasses, forbs, monocots, dicots and foliage. They are fast runners and known for their leaping ability, reaching heights up to 3 m (10 ft).
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Image 14
Water Buffalo
Photo credit: Chmouel Boudjnah
The Water Buffalo is a very large ungulate. It survives in the wild in India, Nepal, Bhutan and Thailand; is very widespread as a domestic animal in Asia, South America. North Africa and Europe; and is feral in northern Australia.
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Image 15
Sahelanthropus tchadensis
Photo: Didier Descouens
A cast of the extinct hominid species Sahelanthropus tchadensis holotype cranium, dubbed "Toumaï", in facio-lateral view. The original cranial fragment is dated to about 7 million years ago and was discovered in Chad. Other than Toumaï, the only Sahelanthropus remains to be discovered are five pieces of jaw and some teeth.
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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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