Mammals Fossil range: Late Triassic – Recent
Giraffe (Giraffa camelopardalis)
Scientific classification
Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata (unranked) Amniota Class: Mammalia Linnaeus, 1758
Subclasses & Infraclasses
Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria

Mammals (class Mammalia) are a class of vertebrate animals characterized by the presence of sweat glands, including sweat glands modified for milk production, hair, three middle ear bones used in hearing, and a neocortex region in the brain. The Triassic is a geologic period that extends from about 251 to 199 Ma (million years ago). ... Image File history File linksMetadata Download high resolution version (1712x2288, 808 KB) Giraffe in its natural environment Photographed by Miroslav Duchacek (from Czech Republic) in Africa. ... Binomial name Linnaeus, 1758 Range map The giraffe (Giraffa camelopardalis) is an African even-toed ungulate mammal, the tallest of all land-living animal species. ... Scientific classification redirects here. ... Phyla Subkingdom Parazoa Porifera (sponges) Subkingdom Agnotozoa Placozoa Orthonectida Rhombozoa Subkingdom Metazoa Radiata Cnidaria Ctenophora - Comb jellies Bilateria Protostomia Acoelomorpha Platyhelminthes - Flatworms Nemertina - Ribbon worms Gastrotricha Gnathostomulida - Jawed worms Micrognathozoa Rotifera - Rotifers Acanthocephala Priapulida Kinorhyncha Loricifera Entoprocta Nematoda - Roundworms Nematomorpha - Horsehair worms Cycliophora Mollusca - Mollusks Sipuncula - Peanut worms Annelida - Segmented... Classes See below Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. ... This article does not cite any references or sources. ... Extant subgroups Synapsida     Mammalia (mammals) Sauropsida    Anapsida        Testudines (turtles)    Diapsida        Lepidosauria           Squamata (lizards and snakes)           Sphenodontida (tuatara)        Archosauria           Crocodilia (crocodiles and alligators)           Aves (birds) The amniotes are a group of vertebrates, comprising the mammals, birds, and various other groups collectively referred to as reptiles. ... Carl Linnaeus, Latinized as Carolus Linnaeus, also known after his ennoblement as  , (May 13, 1707[1] – January 10, 1778), was a Swedish botanist, physician and zoologist[2] who laid the foundations for the modern scheme of nomenclature. ... Suborders   Plagiaulacida   Cimolodonta The Multituberculata are the only major branch of mammals to have become completely extinct, with no living descendants. ... Paraphyletic - Wikipedia /**/ @import /skins-1. ... Prototheria (próto-thiÅ• ee-a) (Gr. ... Infraclasses Metatheria Eutheria This article is about the subclass of mammals. ... Orders ?Symmetrodonta Pantotheria Aegialodontia Eupanthotheria Trituberculata is an extinct group of animals exisiting in the fossil record from about 215 – 85 MYA. It contains the ancestors of Placentalia and Marsupialia; all modern mammals except Monotremata are descended from trituberculates. ... Metatheria is a grouping within the animal class Mammalia. ... Orders[1] Bobolestes Eomaia Maelestes Montanalestes Murtoilestes Prokennalestes Placentalia Superorder Xenarthra: Cingulata (Armadillos) Pilosa (Sloths, True Anteaters) Superorder Afrotheria: Afrosoricida (Tenrecs, etc. ... The Mammals are a modern folk-rock band based in Hudson Valley, NY, USA. The current band members are Michael Merenda Jr. ... A class is the rank in the scientific classification of organisms in biology below Phylum and above Order. ... This article does not cite any references or sources. ... The word Animals when used alone has several possible meanings in the English language. ... Sweating (also called perspiration or sometimes transpiration) is the loss of a watery fluid, consisting mainly of sodium chloride and urea in solution, that is secreted by the sweat glands in the skin of mammals. ... Mammary glands are milk-secreting adaptations of sweat glands and are the characteristic of mammals which gave the class its name. ... This article is about the body feature. ... The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. ... This article is about the skeletal organs. ... Hearing (or audition) is one of the traditional five senses, and refers to the ability to detect sound. ... The neocortex (Latin for new bark or new rind) is a part of the brain of mammals. ...

All mammals other than the monotremes give birth to live young instead of laying eggs. Most mammals also possess specialized teeth, and the largest group of mammals, the placentals, use a placenta during gestation. The mammalian brain regulates endothermic and circulatory systems, including a four-chambered heart. Families Kollikodontidae (extinct) Ornithorhynchidae - Platypus Tachyglossidae - Echidnas Steropodontidae (extinct) Monotremes are mammals that are best known for laying eggs, instead of giving birth to live young like marsupials and placental mammals (Eutheria). ... Types of teeth Molars are used for grinding up foods Carnassials are used for slicing food. ... Orders Superorder Xenarthra: Pilosa Cingulata Infraclass Epitheria: Superorder Afrotheria: Afrosoricida (Golden mole and tenrec) Macroscelidea (Elephant shrew) Tubulidentata (Aardvark) Hyracoidea (Hyrax) Proboscidea (Elephant) Sirenia (Manatee, Dugong) Superorder Laurasiatheria: Chiroptera (Bats) Insectivora (Shrews, Moles) Cetacea (Whale, dolphin) Artiodactyla (Ruminants et al) Perissodactyla(Horse et al. ... The placenta (Latin for cake, referencing its appearance in humans) is an ephemeral organ present in placental vertebrates, such as eutherial mammals and sharks during gestation (pregnancy). ... This article is about the physical effect. ... For transport in plants, see Vascular tissue. ... The heart and lungs, from an older edition of Grays Anatomy. ...

Mammals encompass approximately 5,400 species, ranging in size from the Bumblebee Bat (30-40mm) to the Blue Whale (33 m), distributed in about 1,200 genera, 153 families, and 29 orders,^[1] though this varies by classification scheme. For other uses, see Species (disambiguation). ... Binomial name Craseonycteris thonglongyai Hill, 1974 The Bumblebee Bat, or perhaps more correctly Kittis Hog-nosed Bat, (Craseonycteris thonglongyai or Craseonycterus thonglongyai) is the worlds smallest species of bat and the smallest mammal in the world at 30-40 mm in length and weighing approximately 1. ... Binomial name (Linnaeus, 1758) Blue Whale range Subspecies B. m. ... For other uses, see Genus (disambiguation). ... The hierarchy of scientific classification In biological classification, family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. ... In scientific classification used in biology, the order (Latin: ordo, plural ordines) is a rank between class and family (termed a taxon at that rank). ... For other uses, see Scientific classification (disambiguation). ...

Most mammals belong to the placental group. The four largest orders within the placental mammals are Rodentia (mice, rats, and other small, gnawing mammals), Chiroptera (bats), Carnivora (dogs, cats, bears, and other mammals that primarily eat meat), and Cetartiodactyla (including numerous herbivore species, such as deer, sheep, goats, and buffalos, plus whales). The human species is also a placental mammal, a member of the order Primates. Orders Afrosoricida Macroscelidea Tubulidentata Hyracoidea Proboscidea Sirenia Xenarthra Dermoptera: Scandentia Primates Rodentia Lagomorpha Insectivora Chiroptera Pholidota Carnivora Perissodactyla Artiodactyla Cetacea Placentalia and Eutheria are terms used to describe major groupings within the animal class of Mammalia. ... Suborders Sciuromorpha Castorimorpha Myomorpha Anomaluromorpha Hystricomorpha Rodentia is an order of mammals also known as rodents, characterised by two continuously-growing incisors in the upper and lower jaws which must be kept short by gnawing. ... This article is about mammals. ... Families 17, See classification The diverse order Carnivora (IPA: or ; from Latin carō (stem carn-) flesh, + vorāre to devour) includes over 260 species of placental mammals. ... Orders Order: Cetacea Suborders: Suina Tylopoda Ruminantia Family: Hippopotamidae Humpback Whale breaching. ... This article is about modern humans. ... For the ecclesiastical use of this term, see primate (religion) Families 13, See classification A primate is any member of the biological order Primates, the group that contains all lemurs, monkeys, and apes, including humans. ...

Phylogenetically, Mammalia is defined as all descendants of the most recent common ancestor of monotremes (e.g., echidnas and platypuses) and therian mammals (marsupials and placentals). This means that some extinct groups of "mammals" are not members of the crown group Mammalia, even though most of them have all the characteristics that traditionally would have classified them as mammals. These "mammals" are now usually placed in the unranked clade Mammaliaformes. Phylogenetic groups, or taxa, can be monophyletic, paraphyletic, or polyphyletic. ... The most recent common ancestor (MRCA) of any set of organisms is the most recent individual from which all organisms in the group are directly descended. ... Families †Kollikodontidae Ornithorhynchidae Tachyglossidae †Steropodontidae Monotremes (from the Greek monos single + trema hole, referring to the cloaca) are mammals that lay eggs (Prototheria) instead of giving birth to live young like marsupials (Metatheria) and placental mammals (Eutheria). ... For other senses of this word, see echidna (disambiguation). ... For other uses, see Platypus (disambiguation). ... Infraclasses Metatheria Eutheria This article is about the subclass of mammals. ... This article is about mammals. ... Orders Afrosoricida Macroscelidea Tubulidentata Hyracoidea Proboscidea Sirenia Xenarthra Dermoptera: Scandentia Primates Rodentia Lagomorpha Insectivora Chiroptera Pholidota Carnivora Perissodactyla Artiodactyla Cetacea Placentalia and Eutheria are terms used to describe major groupings within the animal class of Mammalia. ... A crown group is a living monophyletic group or clade, consisting of the last common ancestor of all living examples, plus all of its descendants. ... Clades Allotheria Adelobasileus Sinoconodon Morganucodonta Megazostrodontidae Docodonta Hadrocodium Kuehneotheriidae Symmetrodonta Mammalia Mammaliaformes is a clade that contains the mammals and their closest extinct relatives. ...

The mammalian line of descent diverged from the sauropsid line at the end of the Carboniferous period. The sauropsids would evolve into modern-day reptiles and birds, while the synapsid branch led to mammals. The first true mammals appeared in the Jurassic period. Modern mammalian orders appeared in the Palaeocene and Eocene epochs of the Palaeogene period. Clades Subclass Anapsida Subclass Diapsida Infraclass Lepidosauromorpha Infraclass Archosauromorpha Sauropsids are a diverse group of mostly egg-laying vertebrate animals. ... The Carboniferous is a geologic period and system that extends from the end of the Devonian period, about 359. ... Orders  Crocodilia - Crocodilians scary crocodiles. ... For other meanings of bird, see bird (disambiguation). ... Orders & Suborders Order Pelycosauria * Suborder Caseasauria Suborder Eupelycosauria * Order Therapsida * Suborder Biarmosuchia Suborder Dinocephalia Suborder Anomodontia Suborder Gorgonopsia Suborder Therocephalia Suborder Cynodontia * For complete phylogeny, see text. ... The Jurassic Period is a major unit of the geologic timescale that extends from about 199. ... The Paleocene epoch (65-56 MYA) (early dawn of the recent) is the first geologic epoch of the Palaeogene period in the modern Cenozoic era. ... hfajhfiudshfas == == == --24. ... Palaeogene (alternatively Paleogene) period is a unit of geologic time that began 65 and ended 23 million years ago. ...

Distinguishing features

Living mammal species can be identified by the presence of sweat glands, including those that are specialized to produce milk. Nipple is, generally, the name given to the mammalian nipple, or to things resembling it, such as the tip of an artificial teat or the tip of a grease secreting mechanism in machinery. ... Kittens nursing Lactation describes the secretion of milk from the mammary glands, the process of providing that milk to the young, and the period of time that a mother lactates to feed her young. ... A glass of cows milk. ...

However, other features are required when classifying fossils, since soft tissue glands and some other features are not visible in fossils. Paleontologists use a distinguishing feature that is shared by all living mammals (including monotremes), but is not present in any of the early Triassic synapsids: mammals use two bones for hearing that were used for eating by their ancestors. The earliest synapsids had a jaw joint composed of the articular (a small bone at the back of the lower jaw) and the quadrate (a small bone at the back of the upper jaw). Most reptiles and non-mammalian synapsids use this system including lizards, crocodilians, dinosaurs (and their descendants the birds), and therapsids (mammal-like "reptiles"). Mammals have a different jaw joint, however, composed only of the dentary (the lower jaw bone which carries the teeth) and the squamosal (another small skull bone). In mammals the quadrate and articular bones have become the incus and malleus bones in the middle ear. Note: "non-mammalian synapsids" above implies that mammals are a sub-group of synapsids, and that is exactly what cladistics says they are. A fossil Ammonite Fossils are the mineralized remains of animals or plants or other traces such as footprints. ... Paleontology, palaeontology or palæontology (from Greek: paleo, ancient; ontos, being; and logos, knowledge) is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. ... Families Kollikodontidae (extinct) Ornithorhynchidae - Platypus Tachyglossidae - Echidnas Steropodontidae (extinct) Monotremes are mammals that are best known for laying eggs, instead of giving birth to live young like marsupials and placental mammals (Eutheria). ... The Triassic is a geologic period that extends from about 251 to 199 Ma (million years ago). ... The articular is a bone in the lower jaw of most tetrapods, including reptiles, birds, and amphibians, but has become a middle ear bone (the malleus) in mammals. ... The quadrate is a jaw bone in all jawed vertebrates except mammals (in whom it has become a middle-ear bone, the incus). ... This page is about Lizards, the order of reptile. ... A crocadilian is a crocodile-like dinosaur. ... Orders Saurischia    Sauropodomorpha    Theropoda Ornithischia Dinosaurs are giant reptiles that dominated the terrestrial ecosystem for most of their 165-million year existence. ... Groups Biarmosuchia Dinocephalia Anomodontia Theriodontia    Cynodontia       (...mammals) Therapsids, previously known as the mammal-like reptiles, are a group of synapsids. ... The dentary is the tooth bearing bone of the lower jaw. ... The squamosal is a bone of the head of higher vertebrates. ... This article refers to a bone in the mammalian ear. ... The malleus is hammer-shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum. ... The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. ... It has been suggested that Clade be merged into this article or section. ...

Mammals also have a double occipital condyle: they have two knobs at the base of the skull which fit into the topmost neck vertebra, and other vertebrates have a single occipital condyle. Paleontologists use only the jaw joint and middle ear as criteria for identifying fossil mammals, as it would be confusing if they found a fossil that had one feature, but not the other. The lateral parts of the occipital bone are situated at the sides of the foramen magnum; on their under surfaces are the occipital condyles for articulation with the superior facets of the atlas. ... Typical classes Petromyzontidae (lampreys) Placodermi - extinct Chondrichthyes (cartilaginous fish) Acanthodii - extinct Actinopterygii (ray-finned fish) Actinistia (coelacanths) Dipnoi (lungfish) Amphibia (amphibians) Reptilia (reptiles) Aves (birds) Mammalia (mammals) Vertebrata is a subphylum of chordates, specifically, those with backbones or spinal columns. ...

Anatomy and morphology

Skeletal system

The majority of mammals have seven cervical vertebrae (bones in the neck); this includes bats, giraffes, whales, and humans. The few exceptions include the manatee and the two-toed sloth, which have only six cervical vertebrae, and the three-toed sloth with nine cervical vertebrae. In vertebrates, cervical vertebrae (singular: vertebra) are those vertebrae immediately behind (caudal to) the skull. ... “Chiroptera” redirects here. ... Binomial name Linnaeus, 1758 Range map The giraffe (Giraffa camelopardalis) is an African even-toed ungulate mammal, the tallest of all land-living animal species. ... This article is about the animal. ... For other uses, see Manatee (disambiguation). ... Species Choloepus didactylus Choloepus hoffmanni The two extant species of two-toed sloths are Linnaeuss and Hoffmanns Two-toed Sloth. ... A diagram of a thoracic vertebra. ... Green: , Blue: , Red: Species Bradypus pygmaeus Bradypus torquatus Bradypus tridactylus Bradypus variegatus The three-toed sloths are the only members of the Bradypus genus and the Bradypodidae family. ...

Respiratory system

The lungs of mammals have a spongy texture and are honeycombed with epithelium having a much larger surface area in total than the outer surface area of the lung itself. The lungs of humans are typical of this type of lung. This article is about the epithelium as it relates to animal anatomy. ... The human lungs are the human organs of respiration. ...

Breathing is largely driven by the muscular diaphragm at the bottom of the thorax. Contraction of the diaphragm pulls the bottom of the cavity in which the lung is enclosed downward. Air enters through the oral and nasal cavities; it flows through the larynx and into the trachea, which branches out into bronchi. Relaxation of the diaphragm has the opposite effect, passively recoiling during normal breathing. During exercise, the diaphragm contracts, forcing the air out more quickly and forcefully. The rib cage itself also is able to expand and contract to some degree, through the action of other respiratory and accessory respiratory muscles. As a result, air is sucked into or expelled out of the lungs, always moving down its pressure gradient. This type of lung is known as a bellows lung as it resembles a blacksmith's bellows. In the anatomy of mammals, the diaphragm is a shelf of muscle extending across the bottom of the ribcage. ... A top-down view of skeletal muscle A muscle contraction (also known as a muscle twitch or simply twitch) occurs when a muscle fiber generates tension through the action of actin and myosin cross-bridge cycling. ... This article is about the bones called ribs. ... A large bellows creates a mushroom cloud at the Exploratorium in San Francisco, California. ...

Circulatory system

The mammalian heart has four chambers: the right atrium, right ventricle, left atrium, and left ventricle. Atria are for receiving blood; ventricles are for pumping blood to the lungs and body. The ventricles are larger than the atria and their walls are thick, because muscular walls are needed to forcefully pump the blood from the heart to the body and lungs. Deoxygenated blood from the body enters the right atrium, which pumps it to the right ventricle. The right ventricle pumps blood to the lungs, where carbon dioxide diffuses out, and oxygen diffuses in. From the lungs, oxygenated blood enters the left atrium, where it is pumped to the left ventricle (the largest and strongest of the 4 chambers), which pumps it out to the rest of the body, including the heart's own blood supply. The heart and lungs, from an older edition of Grays Anatomy. ... In anatomy, the atrium (plural: atria) is the blood collection chamber of a heart. ... In the heart, a ventricle is a heart chamber which collects blood from an atrium (another heart chamber that is smaller than a ventricle) and pumps it out of the heart. ... Anterior (frontal) view of the opened heart. ... In the heart, a ventricle is a chamber which collects blood from an atrium (another heart chamber) and pumps it out of the heart. ... For other uses, see Blood (disambiguation). ... The heart and lungs (from an older edition of Grays Anatomy) The lung is an organ belonging to the respiratory system and interfacing to the circulatory system of air-breathing vertebrates. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... diffusion (disambiguation). ... This article is about the chemical element and its most stable form, or dioxygen. ...

Nervous system

All mammalian brains possess a neocortex, a brain region that is unique to mammals. The neocortex (Latin for new bark or new rind) is a part of the brain of mammals. ...

Integumentary system

Mammals have integumentary systems made up of three layers: the outermost epidermis, the dermis, and the hypodermis. This characteristic is not unique to mammals, since it is found in all vertebrates. This article is about the organ. ... Cross-section of all skin layers Optical coherence tomography tomogram of fingertip, depicting stratum corneum (~500µm thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle. ... The dermis is a layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. ... The hypodermis is the lowermost layer of the integumentary system, which is present only in more recently-evolved vertebrates. ... This article does not cite any references or sources. ...

The epidermis is typically ten to thirty cells thick; its main function being to provide a waterproof layer. Its outermost cells are constantly lost; its bottommost cells are constantly dividing and pushing upward. The middle layer, the dermis, is fifteen to forty times thicker than the epidermis. The dermis is made up of many components such as bony structures and blood vessels. The hypodermis is made up of adipose tissue. Its job is to store lipids, and to provide cushioning and insulation. The thickness of this layer varies widely from species to species. Cross-section of all skin layers Optical coherence tomography tomogram of fingertip, depicting stratum corneum (~500µm thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle. ... Adipose tissue is one of the main types of connective tissue. ...

Although mammals and other animals have cilia that superficially may resemble it, no other animals except mammals have hair. It is a definitive characteristic of the order. Some mammals have very little, albeit in obscure parts of their bodies, but nonetheless, careful examination reveals the characteristic. None are known to have hair that naturally is blue or green in color although some cetaceans, along with the mandrills appear to have shades of blue skin. Many mammals are indicated as having blue hair or fur, but in all known cases, it has been found to be a shade of gray. The two-toed sloth and the polar bear may seem to have green fur, but this color is caused by algae growths. cross-section of two cilia, showing 9+2 structure A cilium (plural cilia) is a fine projection from a eukaryotic cell that constantly beats in one direction. ... This article is about the body feature. ... For other uses, see Mandrill (disambiguation). ... Species Choloepus didactylus Choloepus hoffmanni The two extant species of two-toed sloths are Linnaeuss and Hoffmanns Two-toed Sloth. ... This article is about the animal. ... For the programming language, see algae (programming language). ...

Reproductive system

Goat kids will stay with their mother until they are weaned, this is usually about one month

Most mammals give birth to live young (vivipary), but a few, such as the monotremes lay eggs. Live birth also occurs in some non-mammalian species, such as guppies, snakes, and hammerhead sharks; thus it is not a distinguishing characteristic of mammals. Image File history File links Size of this preview: 800 × 534 pixel Image in higher resolution (1600 × 1067 pixel, file size: 453 KB, MIME type: image/jpeg) Domestic goat family of a mother and her two week old kids. ... Image File history File links Size of this preview: 800 × 534 pixel Image in higher resolution (1600 × 1067 pixel, file size: 453 KB, MIME type: image/jpeg) Domestic goat family of a mother and her two week old kids. ... Poa alpina, a grass which shows vivipary: the seeds germinate while still attached to the mother plant. ... Families †Kollikodontidae Ornithorhynchidae Tachyglossidae †Steropodontidae Monotremes (from the Greek monos single + trema hole, referring to the cloaca) are mammals that lay eggs (Prototheria) instead of giving birth to live young like marsupials (Metatheria) and placental mammals (Eutheria). ... In most birds and reptiles, an egg (Latin ovum) is the zygote, resulting from fertilization of the ovum. ... For other uses, see Guppy (disambiguation). ... Species See text. ...

Mammals have sweat glands, a defining feature present only in mammals. Some of these glands produce milk (in what are called mammary glands), a liquid used by newborns as their primary source of nutrition. The monotremes branched from other mammals early on, and do not have the nipples seen in most mammals, but they do have mammary glands. A glass of cows milk. ... Mammary glands are the organs that, in the female mammal, produce milk for the sustenance of the young. ... A human infant The word Infant derives from the Latin in-fans, meaning unable to speak. ... This article is about the anatomical structure. ...

Physiology

Endothermy

Nearly all mammals are endothermic. Most mammals also have hair to help keep them warm. Like birds, mammals can forage or hunt in cold weather and climes where reptiles and large insects cannot.

Endothermy requires plenty of food energy, so pound for pound mammals eat more food than reptiles. Small insectivorous mammals eat prodigious amounts for their size.

A rare exception, the naked mole rat is ectothermic ("cold-blooded"). Birds are also endothermic, so endothermy is not a defining mammalian feature. Binomial name Rüppell, 1842 Distribution of the Naked Mole Rat The naked mole rat (Heterocephalus glaber), also known as the sand puppy, or desert mole rat, is a burrowing rodent native to parts of East Africa and the only species currently classified in genus Heterocephalus. ... For other uses, see Bird (disambiguation). ...

Intelligence

In intelligent mammals, such as primates, the cerebrum is larger relative to the rest of the brain. Intelligence itself is not easy to define, but indications of intelligence include the ability to learn, matched with behavioral flexibility. Rats, for example, are considered to be highly intelligent as they can learn and perform new tasks, an ability that may be important when they first colonize a fresh habitat. In some mammals, food gathering appears to be related to intelligence: a deer feeding on plants has a brain relatively smaller than a cat that must think to outwit its prey.^[2] For the ecclesiastical use of this term, see primate (religion) Families 13, See classification A primate is any member of the biological order Primates, the group that contains all lemurs, monkeys, and apes, including humans. ... The telencephalon (IPA: ) is the name for the forebrain, a large region within the brain to which many functions are attributed. ... For other uses, see Intelligence (disambiguation). ... This is an article about wild rats; for pet rats, see Fancy rat Species 50 species; see text *Several subfamilies of Muroids include animals called rats. ... A biome is a climate and geographical area of ecologically similar communities of plants, animals, and soil organisms, often referred to as ecosystems. ... This article is about the ruminent animal. ... u fuck in ua ... For other uses, see Brain (disambiguation). ... Binomial name Felis catus Linnaeus, 1758 Synonyms Felis lybica invalid junior synonym The cat (or domestic cat, house cat) is a small carnivorous mammal. ...

Social structure

The dependence of the young mammal on its mother for nourishment has made possible a period of training. Such training permits the nongenetic transfer of information between generations. The ability of young mammals to learn from the experience of their elders has allowed a behavioral plasticity unknown in any other group of organisms and has been a primary reason for the evolutionary success of mammals. The possibility of training is one of the factors that has made increased brain complexity a selective advantage. Increased associational potential and memory extend the possibility of learning from experience, and the individual can make adaptive behavioral responses to environmental change. Individual response to short-term change is far more efficient than genetic response. For other uses, see Mother (disambiguation). ... For other uses, see Memory (disambiguation). ...

Some types of mammals are solitary except for brief periods when the female is in estrus. Others, however, form social groups. Such groups may be reproductive or defensive, or they may serve both functions. In those cases that have been studied in detail, a more or less strict hierarchy of dominance prevails. Within the social group, the hierarchy may be maintained through physical combat between individuals, but in many cases stereotyped patterns of behaviour evolve to displace actual combat, thereby conserving energy while maintaining the social structure.

A pronounced difference between sexes (sexual dimorphism) is frequently extreme in social mammals. In large part this is because dominant males tend to be those that are largest or best-armed. Dominant males also tend to have priority in mating or may even have exclusive responsibility for mating within a “harem.” Rapid evolution of secondary sexual characteristics, including size, can take place in a species with such a social structure.

A complex behavior termed “play” frequently occurs between siblings, between members of an age class, or between parent and offspring. Play extends the period of maternal training and is especially important in social species, providing an opportunity to learn behaviour appropriate to the maintenance of dominance.^[3]

Locomotion

See also Animal locomotion In biology and physics, animal locomotion is the study of how animals move, and is part of biophysics. ...

Mammals evolved from four-legged ancestors. They use their limbs to walk, climb, swim, and fly. Some land mammals have toes that produce claws and hooves for climbing and running. Aquatic mammals such as whales and dolphins have fins which evolved from legs.

Terrestrial

An African Elephant

See also Terrestrial locomotion Image File history File links Size of this preview: 450 × 600 pixel Image in higher resolution (768 × 1024 pixel, file size: 571 KB, MIME type: image/jpeg) Recently, due to the work of George W. Bush the elephant population has tripled in the past three months. ... Image File history File links Size of this preview: 450 × 600 pixel Image in higher resolution (768 × 1024 pixel, file size: 571 KB, MIME type: image/jpeg) Recently, due to the work of George W. Bush the elephant population has tripled in the past three months. ... Distribution of Loxodonta africana (2007) Species Loxodonta adaurora (extinct) Loxodonta africana Loxodonta cyclotis African elephants are the two species of elephants in the genus Loxodonta, one of the two existing genera in Elephantidae. ... An example of terrestrial locomotion. ...

Specialization in habitat preference has been accompanied by locomotor adaptations. Terrestrial mammals have a number of modes of progression. The primitive mammalian stock walked plantigrade—that is, with the digits, bones of the midfoot, and parts of the ankle and wrist in contact with the ground. The limbs of ambulatory mammals are typically mobile, capable of considerable rotation.

Mammals modified for running are termed cursorial. The stance of cursorial species may be digitigrade (the complete digits contacting the ground, as in dogs) or unguligrade (only tips of digits contacting the ground, as in horses). In advanced groups limb movement is forward and backward in a single plane. Trinomial name Canis lupus familiaris The dog (Canis lupus familiaris) is a domestic subspecies of the wolf, a mammal of the Canidae family of the order Carnivora. ... Binomial name Equus caballus Linnaeus, 1758 The horse (Equus caballus, sometimes seen as a subspecies of the Wild Horse, Equus ferus caballus) is a large odd-toed ungulate mammal, one of ten modern species of the genus Equus. ...

Saltatory (leaping) locomotion, sometimes called “ricochetal,” has arisen in several unrelated groups (some marsupials, lagomorphs, and several independent lineages of rodents). This mode of locomotion is typically found in mammals living in open habitats. Jumping mammals typically have elongate, plantigrade hind feet, reduced forelimbs, and long tails. Convergent evolution within a given adaptive mode has contributed to the ecological similarity of regional mammalian faunas.

Mammals of several orders have attained great size (elephants, hippopotamuses, and rhinoceroses) and have converged on specializations for a ponderous mode of locomotion referred to as “graviportal.” These animals have no digit reduction and deploy the digits in a circle around the axis of the limb for maximum support, like the pedestal of a column.^[3] Genera and Species Loxodonta Loxodonta cyclotis Loxodonta africana Elephas Elephas maximus Elephas antiquus † Elephas beyeri † Elephas celebensis † Elephas cypriotes † Elephas ekorensis † Elephas falconeri † Elephas iolensis † Elephas planifrons † Elephas platycephalus † Elephas recki † Stegodon † Mammuthus † Elephantidae (the elephants) is a family of pachyderm, and the only remaining family in the order Proboscidea... Binomial name Linnaeus, 1758[2] Range map[1] The hippopotamus (Hippopotamus amphibius), from the Greek ἱπποπόταμος (hippopotamos, hippos meaning horse and potamos meaning river), often shortened to hippo, is a large, mostly plant-eating African mammal, one of only two extant species in the family Hippopotamidae (the other being the Pygmy... For other uses, see Rhinoceros (disambiguation). ...

Arboreal

See also Scansorial locomotion

Well-adapted arboreal mammals frequently are plantigrade, five-toed, and equipped with highly mobile limbs. Some species, including many New World monkeys, have a prehensile tail, which is used like a fifth hand. Brachiation, or “arm walking,” in which the animal hangs from branches and moves by a series of long swings, is an adaptation seen in gibbons. The primitive opposable anthropoid thumb is reduced as a specialization for this method of locomotion. Tarsiers are highly arboreal primates that have expanded pads on the digits to improve grasping, whereas many other arboreal mammals have claws or well-developed nails.^[3] Families Cebidae Aotidae Pitheciidae Atelidae The New World monkeys are the four families of primates that are found in Central and South America: Cebidae, Aotidae, Pitheciidae and Atelidae. ... This article or section does not cite its references or sources. ... Genera Hylobates Hoolock Nomascus Symphalangus Gibbons are the small apes that are grouped in the family Hylobatidae. ... Species Tarsius syrichta Tarsius bancanus Tarsius spectrum Tarsius dianae Tarsius pelengensis Tarsius sangirensis Tarsius pumilus Tarsiers (family Tarsiidae, genus Tarsius) are a genus of prosimian primates, previously classified as strepsirhines, but now classified as haplorhines, though still not considered to be monkeys. ... The kinkajou is an arboreal mammal. ...

Sloths travel slowly along branches rather than swinging energetically. This article is about the South American mammal. ...

Aquatic

Four mammalian groups are fully aquatic. Sirenians (dugongs and manatees) eat plants. Cetaceans (whales, dolphins, and porpoises) and pinnipeds (seals and walruses) eat krill or fish. The sea otter eats a variety of invertebrates and fish. Some semiaquatic mammals are very similar to their close land-borne relatives (otters, muskrats, and water shrews, for example). Other mammals have undergone profound adaptation for swimming and life at sea. Walruses and seals give birth to and nurse their young on land, but cetaceans are completely helpless out of water. They depend on water for mechanical support and thermal insulation.^[3] Buoyed by their aquatic environment, whales have evolved into the largest mammals and indeed the largest animals ever. Families Dugongidae Trichechidae For information about the Gothic Metal band, see Sirenia (band) Sirenia are herbivorous mammals of coastal waters. ... Suborders Mysticeti Odontoceti (see text) The order Cetacea includes whales, dolphins and porpoises. ... Families Odobenidae Otariidae Phocidae Pinnipeds (fin-feet, lit. ... Binomial name Enhydra lutris (Linnaeus, 1758) The Sea Otter (Enhydra lutris) is a large otter native to the North Pacific, from northern Japan and Kamchatka west across the Aleutian Islands south to California. ... Invertebrate is an English word that describes any animal without a spinal column. ... This article is about the carnivorous mammals. ... Binomial name (Linnaeus, 1766) Muskrat range (native range in red, introduced range in green) The muskrat or musquash (Ondatra zibethicus), the only species in genus Ondatra, is a medium-sized semi-aquatic rodent native to North America, and introduced in parts of Europe, Asia, and South America. ... It has been suggested that Echolocating shrew be merged into this article or section. ... For other uses, see Walrus (disambiguation). ... Genera Monachus (Monk Seals) Mirounga (Elephant Seal) Lobodon (Crabeater Seals) Leptonychotes Hydrurga (Leopard Seals) Ommatophoca Erignathus (Bearded Seals) Phoca Halichoerus (Gray Seals) Cystophora (Hooded Seals) The true seals or earless seals are one of the three main groups of mammals within the seal suborder, Pinnipedia. ...

Aerial

Townsends's Big-eared Bat, Corynorhinus townsendii

See also Aerial locomotion Image File history File links Please see the file description page for further information. ... Image File history File links Please see the file description page for further information. ... A number of animals have evolved aerial locomotion, either by powered flight or by gliding. ...

Bats are the only truly flying mammals. Only with active flight have the resources of the aerial habitat been successfully exploited. Mammals belonging to other groups (colugos, marsupials, rodents) are adapted for gliding. A gliding habit is frequently accompanied by scansorial (climbing) locomotion. Many nongliders, such as tree squirrels, are also scansorial.^[3] “Chiroptera” redirects here. ... Species  Cynocephalus varigatus  Cynocephalus volans Colugos are arboreal gliding mammals found in South-east Asia. ... This article is about mammals. ... Suborders Sciuromorpha Castorimorpha Myomorpha Anomaluromorpha Hystricomorpha Rodentia is an order of mammals also known as rodents, characterised by two continuously-growing incisors in the upper and lower jaws which must be kept short by gnawing. ... Subgenera Tenes Sciurus Hesperosciurus Otosciurus Guerlinguetus Hadrosciurus Urosciurus Although the term tree squirrel can refer to any arboreal member of the family Sciuridae, it is generally in reference to the common and widely distributed members of the genus Sciurus. ...

Feeding

To maintain a high constant body temperature is energy expensive- mammals therefore need a nutritious and plentiful diet. While the earliest mammals were probably predators, different species have since adapted to meet their dietary requirements in a variety of ways. Some eat animal prey- this is a carnivorous diet (and includes insectivorous diets). Other mammals, called herbivores, eat plants. An herbivorous diet includes sub-types such as fruit-eating and grass-eating. An omnivore eats boths prey and plants. Carnivorous mammals have a simple digestive tract, because the proteins, lipids, and minerals found in meat require little in the way of specialized digestion. Plants, on the other hand, contain complex carbohydrates, such as cellulose. The digestive tract of a herbivore is therefore host to bacteria that ferment these substances, and make them available for digestion. The bacteria are either housed in the multichambered stomach or in a large cecum. The size of an animal is also a factor in determining diet type. Since small mammals have a high ratio of heat losing surface area to heat generating volume, they tend to have high-energy requirements and a high metabolic rate. Mammals that weigh less than about 18oz (500g) are mostly insectivorous because they cannot tolerate the slow, complex digestive process of a herbivore. Larger animals on the other hand generate more heat and less of this heat is lost. They can therefore tolerate either a slower collection process (those that prey on larger vertebrates) or a slower digestive process (herbivores). Furthermore, mammals that weigh more than 18oz (500g) usually cannot collect enough insects during their waking hours to sustain themselves. The only large insectivorous mammals are those that feed on huge colonies of insects (ants or termites).^[2] For other uses, see Species (disambiguation). ... For other uses, see Animal (disambiguation). ... Prey can refer to: Look up Prey in Wiktionary, the free dictionary A prey animal eaten by a predator in an act called predation. ... Carnivorism redirects here. ... Any organism with a diet that consists chiefly of insects and similar small creatures is an insectivore. ... In zoology, an herbivore is an animal that is adapted to eat primarily plants (rather than meat). ... Crows are omnivores. ... what was here was sick and improperly spelled. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Figure 1: Basic lipid structure. ... Minerals are natural compounds formed through geological processes. ... Carbohydrates (literally hydrates of carbon) are chemical compounds that act as the primary biological means of storing or consuming energy, other forms being fat and protein. ... Cellulose as polymer of β-D-glucose Cellulose in 3D Cellulose (C6H10O5)n is a polysaccharide of beta-glucose. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... In anatomy, the stomach is a bean-shaped hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication. ... The cecum or caecum (from the Latin caecus meaning blind) is a pouch connected to the ascending colon of the large intestine and the ileum. ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... Orders Subclass Apterygota Symphypleona - globular springtails Subclass Archaeognatha (jumping bristletails) Subclass Dicondylia Monura - extinct Thysanura (common bristletails) Subclass Pterygota Diaphanopteroidea - extinct Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Blattodea (cockroaches) Mantodea (mantids) Isoptera (termites) Zoraptera Grylloblattodea Dermaptera (earwigs) Plecoptera (stoneflies) Orthoptera (grasshoppers, crickets... Wikipedia does not yet have an article with this exact name. ... Families Mastotermitidae Kalotermitidae Termopsidae Hodotermitidae Rhinotermitidae Serritermitidae Termitidae Reference: Earthlife as of 2002-07-26 A termite (also known as a white ant) is any member of the order Isoptera, a group of social insects that eat wood and other cellulose-rich vegetable matter. ...

Evolutionary history

For more details on this topic, see Evolution of mammals.

The evolution of mammals from synapsids, also known as mammal-like "reptiles" was a gradual process which took approximately 70 million years, from the mid-Permian to the mid-Jurassic, and by the mid-Triassic there were many species that looked like mammals. Note that synapsids are not reptiles at all, but belong to a distinct lineage of tetrapods. Orders & Suborders Order Pelycosauria * Suborder Caseasauria Suborder Eupelycosauria * Order Therapsida * Suborder Biarmosuchia Suborder Dinocephalia Suborder Anomodontia Suborder Gorgonopsia Suborder Therocephalia Suborder Cynodontia * For complete phylogeny, see text. ... The Permian is a geologic period that extends from about 299. ... The Jurassic Period is a major unit of the geologic timescale that extends from about 199. ... The Triassic is a geologic period that extends from about 251 to 199 Ma (million years ago). ... Groups See text. ...

Evolution

The original synapsid skull structure has one hole behind each eye, in a fairly low position on the skull (lower right in this image).

The first fully terrestrial vertebrates were amniotes. Like the amphibians they evolved from, they had legs and lungs. Amniotes' eggs, however, had internal membranes which allowed the developing embryo to breathe but kept water in. This allowed amniotes to lay eggs on dry land, while amphibians generally need to lay their eggs in water. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Temporal fenestræ refer to cranial holes. ... This article does not cite any references or sources. ... Extant subgroups Synapsida     Mammalia (mammals) Sauropsida    Anapsida        Testudines (turtles)    Diapsida        Lepidosauria           Squamata (lizards and snakes)           Sphenodontida (tuatara)        Archosauria           Crocodilia (crocodiles and alligators)           Aves (birds) The amniotes are a group of vertebrates, comprising the mammals, birds, and various other groups collectively referred to as reptiles. ... For other uses, see Embryo (disambiguation). ...

The first amniotes apparently arose in the late Carboniferous. They descended from amphibians, which were numerous at the time, and lived on land already inhabited by insects, other invertebrates, ferns, mosses, and other plants. Within a few million years two important amniote lineages became distinct: the synapsids, from which mammals are descended; and the sauropsids, from which lizards, snakes, crocodilians, dinosaurs and birds are descended.^[4] Synapsids have a single hole (temporal fenestra) low on each side of the skull. The Carboniferous is a geologic period and system that extends from the end of the Devonian period, about 359. ... Orders & Suborders Order Pelycosauria * Suborder Caseasauria Suborder Eupelycosauria * Order Therapsida * Suborder Biarmosuchia Suborder Dinocephalia Suborder Anomodontia Suborder Gorgonopsia Suborder Therocephalia Suborder Cynodontia * For complete phylogeny, see text. ... Clades Subclass Anapsida Subclass Diapsida Infraclass Lepidosauromorpha Infraclass Archosauromorpha Sauropsids are a diverse group of mostly egg-laying vertebrate animals. ... For other uses, see Lizard (disambiguation). ... For other uses, see Snake (disambiguation). ... Suborders Eusuchia Protosuchia † Mesosuchia † Sebecosuchia † Thalattosuchia † Crocodilia is an order of large reptiles that scientists believe branched off from class Reptilia about 220 million years ago. ... Orders & Suborders Saurischia Sauropodomorpha Theropoda Ornithischia Thyreophora Ornithopoda Marginocephalia Dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years, first appearing approximately 230 million years ago. ... For other uses, see Bird (disambiguation). ... Large holes in the side of the skull. ...

One synapsid group, the pelycosaurs, were the most common land vertebrates of the early Permian and included the largest land animals of the time.^[5] Groups see text The pelycosaurs (from Greek pelyx meaning bowl and sauros meaning lizard) were primitive Late Paleozoic synapsid amniotes. ... The Permian is a geologic period that extends from about 299. ...

Therapsids descended from pelycosaurs in the middle Permian, about 260M years ago, and took over their position as the dominant land vertebrates. They differ from pelycosaurs in several features of the skull and jaws, including: larger temporal fenestrae; incisors which are equal in size.^[6] The therapsids went through a series of stages, beginning with animals which were very like their pelycosaur ancestors and ending with the Triassic cynodonts, some of which could easily be mistaken for mammals: Groups Biarmosuchia Dinocephalia Anomodontia Theriodontia    Cynodontia       (...mammals) Therapsids, previously known as the mammal-like reptiles, are a group of synapsids. ... The Permian is a geologic period that extends from about 299. ... Temporal fenestræ refer to cranial holes. ... Incisors (from Latin incidere, to cut) are the first kind of tooth in heterodont mammals. ... Cynodonta is the order that contains the most mammal-like of the non-mammalian therapsids, which are sometimes termed mammal-like reptiles. The most derived cynodonts