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 viviparousplacental mammals, so named for the temporary organ (placenta) used by offspring to draw nutrition from the mother during gestation.
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...)
The Giant Otter (Pteronura brasiliensis) is an amphibious, mammalian carnivore native to South America. About the length of an adult human being, it is the longest member of the mustelidae, or weasel family, a globally successful group of predators. Unusually for a mustelid, the Giant Otter is a social species, with family groups typically supporting three to eight members. The groups are centred around a dominant breeding pair and are extremely cohesive and cooperative. Although generally peaceful, the species is territorial and aggression has been observed between groups. The Giant Otter is exclusively active during daylight hours. It is the noisiest otter species and distinct vocalizations have been documented that indicate alarm, aggressiveness, and reassurance. The Giant Otter ranges across north-central South America, although its distribution has been greatly reduced and is now discontinuous. The species was listed as endangered in 1999 and population estimates are typically below 5,000 in the wild. The Guianas are the last real stronghold for the species. Decades of poaching for its velvety pelt, peaking in the 1950s and 1960s, decimated population numbers. Habitat degradation and loss is the greatest current threat. The Giant Otter is also rare in captivity: as of 2003, only 60 animals were held.
...from its discovery by John Edward Gray in 1850 until a re-assessment in 1981, the Clymene Dolphin was regarded as sub-species of the Spinner Dolphin.
...the Australian Snubfin Dolphin (Orcaella heinsohni) is a recently recognised species of dolphin first described in 2005.
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.
The Zanzibar red colobus (Procolobus kirkii) is a species of red colobus monkey endemic to Unguja, the main island of the Zanzibar Archipelago. Brought to attention of Western science by Sir John Kirk, this colobus was first described by John Edward Gray in 1868. It is now considered an endangered species, and extensive conservation efforts have been undertaken since the mid-1990s.
A black-tailed prairie dog at the National Zoo in Washington, D.C., looks out from a system of burrows, characteristically scanning the horizon. On average, these rodents grow to between 12 and 16 inches (30 and 40 cm) long, including their short tails.
The Eastern Grey Kangaroo (Macropus giganteus), native to southern and eastern Australia, is the most commonly encountered kangaroo species, as it can be found in and around the major cities within its range. Although males can typically reach a height of 2 metres (6.6 ft) and weigh around 66 kilograms (146 lb), and the scientific name translates to "gigantic large-foot", the Red Kangaroo is actually larger.
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.
The roan antelope (Hippotragus equinus) is a species of savanna antelope found in western, central and southern Africa. Named for its reddish-brown coat, it has a black face with white patches around the eyes and the mouth, and a short erect mane of greyish brown hair extending from the back of the neck to the rump. This roan antelope, of the subspeciesH. e. koba, was photographed in Senegal; the subspecies's range extends from Senegal to Benin in western Africa.
The Indian Palm Squirrel (Funambulus palmarum) is a squirrel native to India and Sri Lanka. It is relatively small, about the size of a rat, with three white stripes on its back from head to tail. According to Hindu legend, Lord Rama was so pleased with a squirrel's help in the construction of a bridge at Rameswaram that he stroked the squirrel's back and his fingers left their mark in the form of stripes.
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.
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).
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.
An Indian palm squirrel (Funambulus palmarum) photographed in Bangalore, India. In India these squirrels are associated with the Hindu deity Rama, an avatar of Vishnu, and as such are not to be harmed. However, in Western Australia they are considered pests and at times targeted for eradication.
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.
A 2-month old domesticgoat (Capra aegagrus hircus) kid in a field of capeweed. Goats are one of the oldest domesticated species. For thousands of years, goats have been used for their milk, meat, hair, and skins over much of the world. Female goats are referred to as does or nannies, intact males as bucks or billies; their offspring are kids.
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.
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