Carnivora

Carnivora

Overview
The diverse order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Carnivora (icon or ˌ; from Latin carō (stem carn-) "flesh", + vorāre "to devour") includes over 260 species of placental
Eutheria
Eutheria is a group of mammals consisting of placental mammals plus all extinct mammals that are more closely related to living placentals than to living marsupials . They are distinguished from noneutherians by various features of the feet, ankles, jaws and teeth...

 mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s. Its members are formally referred to as carnivorans, while the word "carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...

" (often popularly applied to members of this group) can refer to any meat-eating animal. Carnivorans are the most diverse in size of any mammalian order, ranging from the least weasel
Least Weasel
The least weasel is the smallest member of the Mustelidae , native to Eurasia, North America and North Africa, though it has been introduced elsewhere. It is classed as Least Concern by the IUCN, due to its wide distribution and presumably large population...

 (Mustela nivalis), at as little as 25 gram (0.881849052627799 oz) and 11 centimetres (4.3 in), to the polar bear
Polar Bear
The polar bear is a bear native largely within the Arctic Circle encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the world's largest land carnivore and also the largest bear, together with the omnivorous Kodiak Bear, which is approximately the same size...

 (Ursus maritimus), which can weigh up to 1000 kilograms (2,204.6 lb), to the southern elephant seal
Southern Elephant Seal
The Southern Elephant Seal is one of the two extant species of elephant seal. It is both the most massive pinniped and member of the order Carnivora living today...

 (Mirounga leonina), whose adult males weigh up to 5000 kilograms (11,023.1 lb) and measure up to 6.9 metres (22.6 ft) in length.

The first carnivoran was a carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...

, and nearly all carnivorans today primarily eat meat.
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Encyclopedia
The diverse order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Carnivora (icon or ˌ; from Latin carō (stem carn-) "flesh", + vorāre "to devour") includes over 260 species of placental
Eutheria
Eutheria is a group of mammals consisting of placental mammals plus all extinct mammals that are more closely related to living placentals than to living marsupials . They are distinguished from noneutherians by various features of the feet, ankles, jaws and teeth...

 mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s. Its members are formally referred to as carnivorans, while the word "carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...

" (often popularly applied to members of this group) can refer to any meat-eating animal. Carnivorans are the most diverse in size of any mammalian order, ranging from the least weasel
Least Weasel
The least weasel is the smallest member of the Mustelidae , native to Eurasia, North America and North Africa, though it has been introduced elsewhere. It is classed as Least Concern by the IUCN, due to its wide distribution and presumably large population...

 (Mustela nivalis), at as little as 25 gram (0.881849052627799 oz) and 11 centimetres (4.3 in), to the polar bear
Polar Bear
The polar bear is a bear native largely within the Arctic Circle encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the world's largest land carnivore and also the largest bear, together with the omnivorous Kodiak Bear, which is approximately the same size...

 (Ursus maritimus), which can weigh up to 1000 kilograms (2,204.6 lb), to the southern elephant seal
Southern Elephant Seal
The Southern Elephant Seal is one of the two extant species of elephant seal. It is both the most massive pinniped and member of the order Carnivora living today...

 (Mirounga leonina), whose adult males weigh up to 5000 kilograms (11,023.1 lb) and measure up to 6.9 metres (22.6 ft) in length.

The first carnivoran was a carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...

, and nearly all carnivorans today primarily eat meat. Some, such as cats
Felidae
Felidae is the biological family of the cats; a member of this family is called a felid. Felids are the strictest carnivores of the thirteen terrestrial families in the order Carnivora, although the three families of marine mammals comprising the superfamily pinnipedia are as carnivorous as the...

, pinnipeds, and weasels, are obligate carnivores. Others, such as raccoon
Raccoon
Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...

s and bears, depending on the local habitat, are more omnivorous
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...

; the giant panda
Giant Panda
The giant panda, or panda is a bear native to central-western and south western China. It is easily recognized by its large, distinctive black patches around the eyes, over the ears, and across its round body. Though it belongs to the order Carnivora, the panda's diet is 99% bamboo...

 is almost exclusively a herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

, but will take fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

, eggs
Egg (food)
Eggs are laid by females of many different species, including birds, reptiles, amphibians, and fish, and have probably been eaten by mankind for millennia. Bird and reptile eggs consist of a protective eggshell, albumen , and vitellus , contained within various thin membranes...

 and insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s, while the polar bear's harsh habitat forces it to subsist mainly on prey. Carnivorans have teeth, claws, and binocular vision adapted for catching and eating other animals. Many hunt in packs
Pack hunter
A pack hunter is a predator belonging to the animal kingdom, which has evolved to hunt its prey by working together with other members of its species. Normally, such animals are closely related. The most commonly known pack hunter is the Gray Wolf, the ancestor of all breeds of domesticated dogs...

 and are social animal
Social animal
A social animal is a loosely defined term for an organism that is highly interactive with other members of its species to the point of having a recognizable and distinct society.All mammals are social to the extent that mothers and offspring bond...

s, giving them an advantage over larger prey.

Carnivorans apparently evolved in North America out of members of the family Miacidae (miacids) about 42 million years ago. They soon split into cat-like and dog-like forms (Feliformia
Feliformia
The Feliformia are a suborder within the order Carnivora and includes cats , hyenas, mongooses, civets and related taxa. The other suborder of Carnivora is Caniformia...

 and Caniformia
Caniformia
Caniformia, or Canoidea , is a suborder within the order Carnivora. They typically possess a long snout and non-retractile claws . The Pinnipedia evolved from caniform ancestors and are accordingly assigned to this group...

). Their molecular phylogeny shows that the extant Carnivora are a monophyletic group, the crown-group of the Carnivoramorpha
Carnivoramorpha
Carnivoramorpha are a clade of mammals that includes the modern order Carnivora and its closest extinct relatives in the Miacoidea , but excludes the creodonts. The order Creodonta are a sister taxon to the Carnivoramorpha dating back 58.7 million years ago...

.

Distinguishing features



Carnivorans are primarily terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 and usually have strong sharp claw
Claw
A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...

s, with never fewer than four toes on each foot, and well-developed, prominent canine teeth, cheek
Cheek
Cheeks constitute the area of the face below the eyes and between the nose and the left or right ear. They may also be referred to as jowls. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve...

 teeth (premolars and molars) that generally have cutting edges. The last premolar of the upper jaw and first molar of the lower are termed the carnassials or sectorial teeth. These are blade-like teeth that occlude (close) with a scissor-like action for shearing and shredding meat. Carnassials are most highly developed in the Felidae
Felidae
Felidae is the biological family of the cats; a member of this family is called a felid. Felids are the strictest carnivores of the thirteen terrestrial families in the order Carnivora, although the three families of marine mammals comprising the superfamily pinnipedia are as carnivorous as the...

 and the least developed in the Ursidae. Carnivorans have six incisors and two conical
Cone (geometry)
A cone is an n-dimensional geometric shape that tapers smoothly from a base to a point called the apex or vertex. Formally, it is the solid figure formed by the locus of all straight line segments that join the apex to the base...

 canines in each jaw. The only two exceptions to this are the sea otter
Sea Otter
The sea otter is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between 14 and 45 kg , making them the heaviest members of the weasel family, but among the smallest marine mammals...

 (Enhydra lutris), which has four incisors in the lower jaw, and the sloth bear
Sloth Bear
The sloth bear , also known as the labiated bear, is a nocturnal insectivorous species of bear found wild within the Indian subcontinent. The sloth bear evolved from ancestral brown bears during the Pleistocene and shares features found in insect-eating mammals through convergent evolution...

 (Melursus ursinus), which has four incisors in the upper jaw. The number of molars and premolars is variable between carnivoran species, but all teeth are deeply rooted and are diphyodont
Diphyodont
A Diphyodont is an animal with two successive sets of teeth, first the "deciduous" set and later the "permanent" set. Most mammals are Diphyodonts. Diphyodonts contrast with Polyphyodonts, such as many fish, whose teeth are constantly replaced....

. Incisors are retained by carnivorans and the third incisor is commonly large and sharp (canine-like). Carnivorans have either four or five digits on each foot, with the first digit on the forepaws, also known as the dew claw, being vestigial in most species and absent in some.

The Canoidea superfamily (or Caniformia
Caniformia
Caniformia, or Canoidea , is a suborder within the order Carnivora. They typically possess a long snout and non-retractile claws . The Pinnipedia evolved from caniform ancestors and are accordingly assigned to this group...

 suborder) – Canidae
Canidae
Canidae is the biological family of carnivorous and omnivorous mammals that includes wolves, foxes, jackals, coyotes, and domestic dogs. A member of this family is called a canid . The Canidae family is divided into two tribes: Canini and Vulpini...

 (dogs and foxes), Mephitidae (skunks and stink badgers), Mustelidae
Mustelidae
Mustelidae , commonly referred to as the weasel family, are a family of carnivorous mammals. Mustelids are diverse and the largest family in the order Carnivora, at least partly because in the past it has been a catch-all category for many early or poorly differentiated taxa...

 (weasels), Procyonidae
Procyonidae
Procyonidae is a New World family of the order Carnivora. It includes the raccoons, coatis, kinkajous, olingos, ringtails and cacomistles. Procyonids inhabit a wide range of environments, and are generally omnivorous.-Characteristics:...

 (raccoons), Ursidae (bears), Otariidae (eared seals), Odobenidae
Odobenidae
Odobenidae is a family of Pinnipeds. The only living species is walrus.In the past, however, the group was much more diverse, and includes more than ten fossil genera.- Taxonomy :All genera, except Odobenus, are extinct.*Prototaria...

 (walrus), and Phocidae (earless seals) (the last three families formerly classified in the suborder Pinnipedia) and the extinct family Amphicyonidae (bear-dogs) – are characterized by having nonchambered or partially chambered auditory bullae, nonretractable claws, and a well-developed baculum
Baculum
The baculum is a bone found in the penis of most mammals. It is absent in humans, but present in other primates, such as the gorilla and chimpanzee.The bone aids in sexual intercourse.-Purpose:...

. Most species are rather simply colored, lacking the flashy spotted or rosetted coats like many species of felids and viverrids have. This is because Canoidea tend to range in the temperate and subarctic biomes, although Mustelidae and Procyonidae have a few tropical species. Most are terrestrial, although a few species, like procyonids, are arboreal. All families except the Canidae and a few species of Mustelidae are plantigrade. Diet is varied and most tend to be omnivorous to some degree, and thus the carnassial teeth are less specialized. Canoidea have more premolars and molars in an elongated skull.

The Feloidea superfamily (or Feliformia
Feliformia
The Feliformia are a suborder within the order Carnivora and includes cats , hyenas, mongooses, civets and related taxa. The other suborder of Carnivora is Caniformia...

 suborder)– Felidae
Felidae
Felidae is the biological family of the cats; a member of this family is called a felid. Felids are the strictest carnivores of the thirteen terrestrial families in the order Carnivora, although the three families of marine mammals comprising the superfamily pinnipedia are as carnivorous as the...

 (cats), Prionodontidae (Asiatic linsangs), Herpestidae (mongooses), Hyaenidae (hyenas), Viverridae (civets), and Eupleridae
Eupleridae
The family Eupleridae is a group of carnivorans endemic to Madagascar and comprising 10 known species in seven genera. Probably the best known species is the Fossa , in the subfamily Euplerinae...

 (Malagasy carnivorans), as well as the extinct family Nimravidae
Nimravidae
The Nimravidae, sometimes known as false saber-toothed cats, are an extinct family of mammalian carnivores belonging to the suborder Feliformia and endemic to North America, Europe, and Asia living from the Eocene through the Miocene epochs , existing for approximately .-Morphology:Although some...

 (paleofelids) – often have spotted, rosetted or striped coats, and tend to be more brilliantly colored than their Canoidean counterparts. This is because these species tend to range in tropical habitats, although a few species do inhabit temperate and subarctic habitats. Many are arboreal or semiarboreal, and the majority are digitigrade. Diet tends to be more strictly carnivorous, especially in the Felidae family. They have fewer teeth and shorter skulls, with much more specialized carnassials meant for shearing meat. Felidae claws are retractile, or rarely, semiretractile. The terminal phalanx, with the claw attached, folds back in the fore-foot into a sheath by the outer side of the middle phalanx of the digit, and is retained in this position when at rest by a strong elastic ligament. In the hind-foot, the terminal joint or phalanx is retracted on to the top, and not the side of the middle phalanx. Deep flexor muscles straighten the terminal phalanges, so the claws protrude from their sheaths, and the soft "velvety" paw becomes suddenly converted into a formidable weapon. The habitual retraction of the claws preserves their points from wear.

The Pinnipedia superfamily (walruses, seals, and sea lions), now considered to be part of Caniformia, are medium to large (to 6.5 m) aquatic mammals. Being homeothermic (warm-blooded) marine mammals, pinnipeds need a low surface area to body mass ratio. Otherwise, they would suffer from excessive heat loss due to water's high capacity for heat conduction. The body is usually insulated with a thick layer of fat called blubber
Blubber
Blubber is a thick layer of vascularized adipose tissue found under the skin of all cetaceans, pinnipeds and sirenians.-Description:Lipid-rich, collagen fiber–laced blubber comprises the hypodermis and covers the whole body, except for parts of the appendages, strongly attached to the musculature...

 and typically covered with hair. The digits are not separate, but connected by a thick web that forms flippers for swimming; thus, the forelimbs and hindlimbs are transformed into paddles. This enables them to dive at extreme depths (600 meters for the Weddell seal
Weddell Seal
The Weddell seal , is a relatively large and abundant true seal with a circumpolar distribution surrounding Antarctica. Weddell seals have the most southerly distribution of any mammal, with a habitat that extends as far south as McMurdo Sound...

). They can remain underwater for long periods of time, sometimes an hour or more, but most dives are usually short. The facial region of skull is relatively small, with pinnae very small or lacking, and the vibrissae
Vibrissae
Vibrissae , or whiskers, are specialized hairs usually employed for tactile sensation. The term may also refer to the thick hairs found inside human nostrils, but these have no sensorial function and only operate as an airborne particulate barrier...

 are well developed. The molariform teeth are mostly homodont and the canines are well developed. The tail is very short or absent, the ears are small or absent as well, and the external genitalia are hidden in slits or depressions in the body.

Skull structure



Members of Carnivora have a characteristic skull shape with relatively large brains encased in a heavy skull. The skull has a highly developed zygomatic arch
Zygomatic arch
The zygomatic arch or cheek bone is formed by the zygomatic process of temporal bone and the temporal process of the zygomatic bone , the two being united by an oblique suture; the tendon of the Temporalis passes medial to the arch to gain insertion into the coronoid process...

 just behind the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...

 (common to all mammals and their cynodont
Cynodont
Cynodontia or cynodonts are a taxon of therapsids which first appeared in the Late Permian and were eventually distributed throughout all seven continents by the Early Triassic . This clade includes modern mammals and their extinct close relatives. They were one of the most diverse groups of...

 forebears), and they have ossified external auditory bullae. Feloidea have a two-chambered auditory bullae. In addition to allowing extra room for the passage of muscles to work the lower jaw, the zygomatic arch also allows for differentiation of separate muscle groups to be involved in biting and chewing. Masseters attach from the dentary (specifically, the masseteric fossa) to the zygomatic arch and onto the maxilla in front of the arch, providing crushing force. The temporalis attaches from the dentary (specifically, the coronoid process
Coronoid process of the mandible
The mandible's coronoid process is a thin, triangular eminence, which is flattened from side to side and varies in shape and size....

) to the side of the braincase, providing torque about the axis of jaw articulation. In comparing the skulls of carnivores and herbivores, it can be seen that the shearing force of the temporalis is somewhat more important to carnivores, which have more room on the braincase (this is not unrelated to carnivoran intelligence) and commonly develop a sagittal crest
Sagittal crest
A sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull of many mammalian and reptilian skulls, among others....

 (running from posterior to anterior on the skull), providing yet additional room for temporalis attachment. Carnivoran jaws can only move on a vertical axis, in an up-and-down motion, and cannot move from side-to-side. The jaw joint in carnivores tends to lie within the plane of tooth occlusion, an arrangement that further emphasizes shearing (as in a pair of scissors). In herbivores, the crushing force of the masseters is relatively more important than is shearing. The jaw joint is generally well above the plane of tooth occlusion, allowing extra room for masseteric attachment on the dentary and causing the rotation of the lower jaw to be translated into straight-ahead crushing force between the teeth of the upper and lower jaws.

Physiology


Carnivora have a simple stomach designed to digest primarily meat, as compared to the elaborate digestive systems of herbivorous animals, which are necessary to break down tough, complex plant fibers. The caecum is either absent or short and simple, and the colon is not sacculated or much wider than the small intestine. Most species of Carnivora are, to some degree, omnivorous, except the Felidae and Pinnipedia, which are obligate carnivores. Most have highly-developed senses, especially vision and hearing, and often a highly acute sense of smell in many species, such as in the Canoidea. They are excellent runners: some are long-distance runners, but more commonly are sprinters. Even bears and raccoons, although seemingly slow and clumsy, are capable of remarkable bursts of speed.

Diet specializations


Carnivorans include carnivores, omnivores, and even a few primarily herbivorous species, such as the giant panda
Giant Panda
The giant panda, or panda is a bear native to central-western and south western China. It is easily recognized by its large, distinctive black patches around the eyes, over the ears, and across its round body. Though it belongs to the order Carnivora, the panda's diet is 99% bamboo...

. Important teeth for carnivorans are the large, slightly recurved canines, used to dispatch prey, and the carnassial complex, used to rend meat from bone and slice it into digestible pieces. Dogs have molar teeth behind the carnassials for crushing bones, but cats have only a greatly reduced, functionless molar behind the carnassial in the upper jaw. Cats will strip bones clean but will not crush them to get the marrow inside. Omnivores, such as bears and raccoons, have developed blunt, molar-like carnassials. Carnassials are a key adaptation for terrestrial vertebrate predation; all other placental orders are primarily herbivores, insectivores, or aquatic.

Reproductive system



Carnivorans tend to produce a single litter annually, but some produce multiple litters a year, and larger carnivorans, like bears, have gaps of 2–3 years between litters. The average gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....

 period lies between 50 and 115 days, although the ursids and mustelids have delayed implantation, thus extending the gestation period 6–9 months beyond the normal period. Litter sizes are usually small, ranging from 1–13 young, which are born with underdeveloped eyes and ears. In most species, the mother has exclusive or at least primary care of the offspring. Many species of carnivorans are solitary, but a few are gregarious.

Phylogeny


Carnivorans evolved out of members of the paraphyletic family Miacidae (miacids). The transition from Miacidae to Carnivora was a general trend in the middle and late Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

, with taxa from both North America and Eurasia involved. The divergence of carnivorans from other miacids, as well as the divergence of the two clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

s within Carnivora, Caniformia
Caniformia
Caniformia, or Canoidea , is a suborder within the order Carnivora. They typically possess a long snout and non-retractile claws . The Pinnipedia evolved from caniform ancestors and are accordingly assigned to this group...

 and Feliformia
Feliformia
The Feliformia are a suborder within the order Carnivora and includes cats , hyenas, mongooses, civets and related taxa. The other suborder of Carnivora is Caniformia...

, is now inferred to have happened in the middle Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

, about 42 million years ago (mya). Traditionally, the extinct family Viverravidae (viverravids) had been thought to be the earliest carnivorans, with fossil records first appearing in the Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

 of North America about 60 mya, but recently described evidence from cranial morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....

 now places them outside the order Carnivora.

The Miacidae are not a monophyletic group, but a paraphyletic array of stem taxa. Today, Carnivora is restricted to the crown group
Crown group
A crown group is a group consisting of living representatives, their ancestors back to the most recent common ancestor of that group, and all of that ancestor's descendants. The name was given by Willi Hennig, the formulator of phylogenetic systematics, as a way of classifying living organisms...

, and Carnivora and miacoids
Miacoidea
Miacoidea is paraphyletic superfamily that had been traditionally divided into two families of carnivores: Miacidae and Viverravidae. Miacoids were primitive carnivores which lived during the Paleocene and Eocene Epoch about 33-65 million years ago...

 are grouped in the clade Carnivoramorpha
Carnivoramorpha
Carnivoramorpha are a clade of mammals that includes the modern order Carnivora and its closest extinct relatives in the Miacoidea , but excludes the creodonts. The order Creodonta are a sister taxon to the Carnivoramorpha dating back 58.7 million years ago...

, and the miacoids are regarded as basal carnivoramorphs. Based on dental features and braincase sizes, it is now known that Carnivora must have evolved from a form even more primitive than Creodonta, and thus these two orders may not even be sister groups. The Carnivora, Creodonta, Pholidota, and a few other extinct orders are informally grouped together in the clade Ferae
Ferae
Ferae is a clade of mammals, consisting of the orders Carnivora and Pholidota . Pangolins do not look much like carnivorans , and were thought to be the closest relatives of Xenarthra...

. Older classification schemes divided the order into two suborders: Fissipedia
Fissipedia
Fissipedia is a former biological suborder comprising the largely land-based families of the order Carnivora. By and large, members of this suborder are meat-eaters, with the giant panda and red panda being the most notable exceptions.In some former taxonomic classifications, Pinnipedia is...

 (which included the families of primarily land Carnivora) and Pinnipedia (which included the true seals, eared seal
Eared Seal
The eared seals or otariids are marine mammals in the family Otariidae, one of three groupings of Pinnipeds. They comprise 16 species in seven genera commonly known either as sea lions or fur seals, distinct from true seals and the Walrus...

s, and walrus
Walrus
The walrus is a large flippered marine mammal with a discontinuous circumpolar distribution in the Arctic Ocean and sub-Arctic seas of the Northern Hemisphere. The walrus is the only living species in the Odobenidae family and Odobenus genus. It is subdivided into three subspecies: the Atlantic...

). However, it is now recognized that the Fissipedia is a paraphyletic group and that the pinnipeds were not the sister group to the fissipeds but rather had arisen from among them.

Carnivora are generally divided into the suborders Feliformia (cat-like) and Caniformia (dog-like), the latter of which includes the pinniped
Pinniped
Pinnipeds or fin-footed mammals are a widely distributed and diverse group of semiaquatic marine mammals comprising the families Odobenidae , Otariidae , and Phocidae .-Overview: Pinnipeds are typically sleek-bodied and barrel-shaped...

s. The pinnipeds are part of a clade, known as the Arctoidea
Arctoidea
Arctoidea is a superfamily of extinct and extant mostly carnivorous mammals which include the extinct group Hemicyonidae , and extant groups Musteloidea , Nothocyon, Pinnipedia , and Ursidae , found in all continents from the Eocene, 46 Ma ago, to the present, approximately ..-Taxonomy:Arctoidea...

, which also includes the Ursidae (bears) and the superfamily Musteloidea. The Musteloidea in turn consists of the Mustelidae
Mustelidae
Mustelidae , commonly referred to as the weasel family, are a family of carnivorous mammals. Mustelids are diverse and the largest family in the order Carnivora, at least partly because in the past it has been a catch-all category for many early or poorly differentiated taxa...

 (mustelids: weasels), Procyonidae
Procyonidae
Procyonidae is a New World family of the order Carnivora. It includes the raccoons, coatis, kinkajous, olingos, ringtails and cacomistles. Procyonids inhabit a wide range of environments, and are generally omnivorous.-Characteristics:...

 (procyonids: raccoons), Mephitidae (skunks) and Ailurus (red panda). The oldest caniforms are the Miacis
Miacis
The 'genus' Miacis contains extinct species of carnivorous mammals that appeared in the late Paleocene and continued through the Eocene. The genus Miacis is not monophyletic but a diverse collection of species that belong to the stemgroup within the Carnivoramorpha...

species Miacis cognitus, the Amphicyonidae (bear-dogs) such as Daphoenus
Daphoenus
Daphoenus is an extinct member of the family Amphicyonidae belonging to the class Mammalia, an extinct order of terrestrial carnivores belonging to the suborder Caniformia, which inhabited North America from the Early Eocene subepoch to the Early Miocene subepoch 42—16.3 Mya, existing for...

, and Hesperocyon
Hesperocyon
Hesperocyon is an extinct genus of canids, family of Canidae and subfamily Hesperocyoninae which was endemic to North America from southern Canada to appearing during the Uintan age-Bridgerian age of the Mid-Eocene 42.5 mya—31.0 Ma. . Hesperocyon existed for approximately .-Taxonomy:Hesperocyon...

(of the family Canidae, subfamily Hesperocyoninae). Hesperocyonine canids first appeared in North America, and the earliest species is currently dated at 39.74 mya, but they were not represented in Europe until well into the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

, and not into Asia and Africa until the Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...

. Miacis and Amphicyonidae were the first of the caniforms to split from the others and are sometimes considered to be sister groups to Ursidae, but the exact closeness of Amphicyonidae and Ursidae, as well as Arctoidae to Ursidae, is still uncertain. The Canidae
Canidae
Canidae is the biological family of carnivorous and omnivorous mammals that includes wolves, foxes, jackals, coyotes, and domestic dogs. A member of this family is called a canid . The Canidae family is divided into two tribes: Canini and Vulpini...

 (wolves, coyotes, jackals, foxes and dogs) are generally considered to be the sister group to Arctoidea. The Ursidae first occur in North America in the Late Eocene (ca. 38 mya) as the very small and graceful Parictis
Parictis
Parictis is the earliest genus of bear known. It was a very small and graceful ursid with a skull only 7 cm long. Parictis first appeared in North America in the Late Eocene , but it did not arrive in Eurasia and Africa until the Miocene...

that had a skull only 7 cm long. Like the canids, this family does not appear in Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

 and Africa until the Miocene. The other caniform families Amphicyonidae, Mustelidae and Procyonidae occur in both the Old World and the New World by the Late Eocene and Early Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

.

The ancestor of all Feliformia evolved from the Caniformia-Feliformia split. Nandinia, the African palm civet, seems to be the most primitive of all the feliforms and the very first to split from the others. The Asiatic linsangs of the genus Prionodon (traditionally placed in the Viverridae) form a family of their own, as some recent studies indicate that Prionodon is actually the closest living relative to the cats. The Nimravidae
Nimravidae
The Nimravidae, sometimes known as false saber-toothed cats, are an extinct family of mammalian carnivores belonging to the suborder Feliformia and endemic to North America, Europe, and Asia living from the Eocene through the Miocene epochs , existing for approximately .-Morphology:Although some...

 are sometimes seen as the most basal of all feliforms and the first to split from the others, but there is a possibility that Nimravidae might not even belong within the order, and therefore its position as a clade within Carnivora is currently unstable. Other studies indicate that barbourofelids
Barbourofelidae
Barbourofelidae is an extinct family of mammalian carnivores of the suborder Feliformia, which lived in North America, Eurasia and Africa during the Miocene epoch , existing for approximately .- Taxonomy :...

 forms a separate family, which is closely related to the true felids instead of being related to the nimravids. Recognizable nimravid fossils date from the late Eocene (37 mya), from the Chadronian White River Carnivora Formation at Flagstaff Rim, Wyoming. Nimravid diversity appears to have peaked about 28 mya. The hypercarnivorous
Hypercarnivore
A hypercarnivore is an animal which has a diet that is more than 70% meat, with the balance consisting of non-animal foods such as fungi, fruits or other plant material. Some examples include the big cats, dolphins, eagles, snakes, marlin, most sharks, and such invertebrates as octopuses and sea...

 (strictly meat-eating) nimravid feliforms were extinct in North America after 26 mya and felids did not arrive in North America until the early middle Miocene (16 mya).

It has been suggested that canids evolved hypercarnivorous morphologies because feliforms were absent during this period (the "cat-gap", 26-18.5 mya), however recent data do not support this hypothesis. Hypercarnivore feliforms (felids and nimravids) occupied an area that canids did not and where felids, nimravids, and hypercarnivorous creodonts are found. Hypercarnivorous canids were present before the disappearance of the nimravids, and all went extinct before the appearance of felids. Following the extinction of nimravids, only three taxa originated, two of which were relatively small in body size. Disparity increased during the "cat-gap" even with the extinction of the hypercarnivorous extremes. This was due to the extinction of morphological intermediates, and because carnivorans began to occupy hypocarnivorous (nonmeat-specialist) morphospace for the first time in North America. Procyonids did not arrive in North America until the early Miocene, and "modern" ursids (e.g., Ursinae
Ursinae
Ursinae is a subfamily of Ursidae named by Swainson though probably named before Hunt 1998. It was assigned to Ursidae by Bjork , Hunt and Jin et al...

), did not arrive until the late Miocene. Extinct lineages of Ursidae were present in North America from the late Eocene through the Miocene and Amphicyonid (bear-dogs) were present during this period as well, but occupied a morphospace generally shared with canids and not in close proximity to ursids. A large question remains as to why there was a progressive decline in hypercarnivorous carnivoramorphans during the late Oligocene/early Miocene. During this period all hypercarnivorous forms disappeared from the fossil record, including hypercarnivorous feliforms, canids, and mustelids. One possible explanation is climate change. Earth was gradually cooling after the late Paleocene, and over a period spanning the Eocene/Oligocene boundary, a dramatic climatic cooling event occurred.

A recent study finally resolves the exact position of Ailurus: the red panda is neither a procyonid nor an ursid, but forms a monotypic family, with the other musteloids as its closest living relatives. The same study also shows that the mustelids are not a primitive family, as was once thought. Their small body size is a secondary trait — the primitive body form of the arctoids was large, not small. Recent molecular studies also suggest that the endemic Carnivora
Eupleridae
The family Eupleridae is a group of carnivorans endemic to Madagascar and comprising 10 known species in seven genera. Probably the best known species is the Fossa , in the subfamily Euplerinae...

 of Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...

, including three genera usually classed with the civets and four genera of mongoose
Mongoose
Mongoose are a family of 33 living species of small carnivorans from southern Eurasia and mainland Africa. Four additional species from Madagascar in the subfamily Galidiinae, which were previously classified in this family, are also referred to as "mongooses" or "mongoose-like"...

s classed with the Herpestidae, are all descended from a single ancestor. They form a single sister taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

 to the Herpestidae. The hyena
Hyena
Hyenas or Hyaenas are the animals of the family Hyaenidae of suborder feliforms of the Carnivora. It is the fourth smallest biological family in the Carnivora , and one of the smallest in the mammalia...

s are also closely related to this clade.

Classification





  • ORDER CARNIVORA
    • Suborder Feliformia
      Feliformia
      The Feliformia are a suborder within the order Carnivora and includes cats , hyenas, mongooses, civets and related taxa. The other suborder of Carnivora is Caniformia...

       ("cat-like")
      • Family
        Extinction
        In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...

        Stenoplesictidae
        Stenoplesictidae
        Stenoplesictidae is a family of extinct civet-like animals, such as Stenoplesictis....

      • Family †Percrocutidae
        Percrocutidae
        The Percrocutidae form an extinct family of hyena-like feliform carnivores endemic to Asia, Africa, and Southern Europe from the Miocene through Pliocene living 20—2.59 Ma existing for approximately ....

      • Family †Nimravidae
        Nimravidae
        The Nimravidae, sometimes known as false saber-toothed cats, are an extinct family of mammalian carnivores belonging to the suborder Feliformia and endemic to North America, Europe, and Asia living from the Eocene through the Miocene epochs , existing for approximately .-Morphology:Although some...

        : false sabre-tooth cats (5–36 mya)
      • Family Nandiniidae: African palm civet
        African Palm Civet
        The African palm civet , also known as the two-spotted palm civet, is a small mammal, with short legs, small ears, a body resembling a cat, and a long lithe tail as long as its body. Adults usually weigh . It is native to the forests of eastern Africa, where it usually inhabits trees...

        ; 1 species in 1 genus
      • Superfamily Feloidea
        • Family Prinonodontidae: Asiatic linsangs; 2 species in 1 genus
        • Family †Barbourofelidae
          Barbourofelidae
          Barbourofelidae is an extinct family of mammalian carnivores of the suborder Feliformia, which lived in North America, Eurasia and Africa during the Miocene epoch , existing for approximately .- Taxonomy :...

           (6–18 mya)
        • Family Felidae
          Felidae
          Felidae is the biological family of the cats; a member of this family is called a felid. Felids are the strictest carnivores of the thirteen terrestrial families in the order Carnivora, although the three families of marine mammals comprising the superfamily pinnipedia are as carnivorous as the...

          : cats; 40 species in 14 genera
      • Infraorder Viverroidea
        • Family Viverridae: civet
          Civet
          The family Viverridae is made up of around 30 species of medium-sized mammal, including all of the genets, the binturong, most of the civets, and the two African linsangs....

          s and allies; 35 species in 15 genera
        • Superfamily Herpestoidea
          • Family Hyaenidae: hyena
            Hyena
            Hyenas or Hyaenas are the animals of the family Hyaenidae of suborder feliforms of the Carnivora. It is the fourth smallest biological family in the Carnivora , and one of the smallest in the mammalia...

            s and aardwolf
            Aardwolf
            The aardwolf is a small, insectivorous mammal, native to Eastern and Southern Africa. The name means "earth wolf" in Afrikaans/Dutch. It is also called "maanhaar jackal". It is related to hyenas, but unlike its relatives, it does not hunt large prey. This unusual animal preys on insects...

            ; 4 species in 4 genera
          • Family Eupleridae
            Eupleridae
            The family Eupleridae is a group of carnivorans endemic to Madagascar and comprising 10 known species in seven genera. Probably the best known species is the Fossa , in the subfamily Euplerinae...

            : Malagasy carnivorans; 8 species in 7 genera
          • Family Herpestidae: mongoose
            Mongoose
            Mongoose are a family of 33 living species of small carnivorans from southern Eurasia and mainland Africa. Four additional species from Madagascar in the subfamily Galidiinae, which were previously classified in this family, are also referred to as "mongooses" or "mongoose-like"...

            s and allies; 33 species in 14 genera
    • Suborder Caniformia
      Caniformia
      Caniformia, or Canoidea , is a suborder within the order Carnivora. They typically possess a long snout and non-retractile claws . The Pinnipedia evolved from caniform ancestors and are accordingly assigned to this group...

       ("dog-like")
      • Family †Amphicyonidae: bear-dogs (9–37 mya)
      • Family Canidae
        Canidae
        Canidae is the biological family of carnivorous and omnivorous mammals that includes wolves, foxes, jackals, coyotes, and domestic dogs. A member of this family is called a canid . The Canidae family is divided into two tribes: Canini and Vulpini...

        : dog
        Dog
        The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

        s and allies; 37 species in 10 genera
      • Infraorder Arctoidea
        Arctoidea
        Arctoidea is a superfamily of extinct and extant mostly carnivorous mammals which include the extinct group Hemicyonidae , and extant groups Musteloidea , Nothocyon, Pinnipedia , and Ursidae , found in all continents from the Eocene, 46 Ma ago, to the present, approximately ..-Taxonomy:Arctoidea...

        • Superfamily Ursoidea
          • Family †Hemicyonidae
            Hemicyonidae
            Hemicyonidae is an extinct family of so-called "dog-bears", literally "Half Dog" , bear-like carnivoran living in Europe, North America, Africa, and Asia during the Oligocene through Miocene epochs 33.9—5.3 Ma, existing for approximately ....

            : (2–22 mya)
          • Family Ursidae: bear
            Bear
            Bears are mammals of the family Ursidae. Bears are classified as caniforms, or doglike carnivorans, with the pinnipeds being their closest living relatives. Although there are only eight living species of bear, they are widespread, appearing in a wide variety of habitats throughout the Northern...

            s; 8 species in 5 genera
        • Superfamily Musteloidea
          Musteloidea
          Musteloidea is a superfamily of carnivoran mammals united by shared characters of the skull and teeth. Musteloids share a common ancestor with the pinnipeds, the group which includes seals....

          • Family Ailuridae
            Ailuridae
            Ailuridae is a family in the mammal order Carnivora. The family includes the Red Panda and its extinct relatives.-Classification history:...

            : red panda
            Red Panda
            The red panda , is a small arboreal mammal native to the eastern Himalayas and southwestern China. It is the only species of the genus Ailurus. Slightly larger than a domestic cat, it has reddish-brown fur, a long, shaggy tail, and a waddling gait due to its shorter front legs...

            ; 1 species in 1 genus.
          • Family Mephitidae: skunk
            Skunk
            Skunks are mammals best known for their ability to secrete a liquid with a strong, foul odor. General appearance varies from species to species, from black-and-white to brown or cream colored. Skunks belong to the family Mephitidae and to the order Carnivora...

            s and stink badgers; 10 species in 4 genera
          • Family Mustelidae
            Mustelidae
            Mustelidae , commonly referred to as the weasel family, are a family of carnivorous mammals. Mustelids are diverse and the largest family in the order Carnivora, at least partly because in the past it has been a catch-all category for many early or poorly differentiated taxa...

            : weasel
            Weasel
            Weasels are mammals forming the genus Mustela of the Mustelidae family. They are small, active predators, long and slender with short legs....

            s, marten
            Marten
            The martens constitute the genus Martes within the subfamily Mustelinae, in family Mustelidae.-Description:Martens are slender, agile animals, adapted to living in taigas, and are found in coniferous and northern deciduous forests across the northern hemisphere. They have bushy tails, and large...

            s, badger
            Badger
            Badgers are short-legged omnivores in the weasel family, Mustelidae. There are nine species of badger, in three subfamilies : Melinae , Mellivorinae , and Taxideinae...

            s, wolverine
            Wolverine
            The wolverine, pronounced , Gulo gulo , also referred to as glutton, carcajou, skunk bear, or quickhatch, is the largest land-dwelling species of the family Mustelidae . It is a stocky and muscular carnivore, more closely resembling a small bear than other mustelids...

            s, mink
            Mink
            There are two living species referred to as "mink": the European Mink and the American Mink. The extinct Sea Mink is related to the American Mink, but was much larger. All three species are dark-colored, semi-aquatic, carnivorous mammals of the family Mustelidae, which also includes the weasels and...

            s, ferret
            Ferret
            The ferret is a domesticated mammal of the type Mustela putorius furo. Ferrets are sexually dimorphic predators with males being substantially larger than females. They typically have brown, black, white, or mixed fur...

            s, and otter
            Otter
            The Otters are twelve species of semi-aquatic mammals which feed on fish and shellfish, and also other invertebrates, amphibians, birds and small mammals....

            s; 55 species in 24 genera
          • Family Procyonidae
            Procyonidae
            Procyonidae is a New World family of the order Carnivora. It includes the raccoons, coatis, kinkajous, olingos, ringtails and cacomistles. Procyonids inhabit a wide range of environments, and are generally omnivorous.-Characteristics:...

            : raccoons
            Procyon (genus)
            Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...

             and allies; 19 species in 6 genera
        • Superfamily Pinnipedia
          • Family †Enaliarctidae
            Enaliarctos
            Enaliarctos is an extinct genus of pinniped.Prior to the discovery of Puijila, the five species in the genus Enaliarctos represented the oldest known pinniped fossils, having been recovered from late Oligocene and early Miocene strata of California and Oregon.It had a short tail and developed...

            : (23–20 mya?)
          • Family Odobenidae
            Odobenidae
            Odobenidae is a family of Pinnipeds. The only living species is walrus.In the past, however, the group was much more diverse, and includes more than ten fossil genera.- Taxonomy :All genera, except Odobenus, are extinct.*Prototaria...

            : walrus
            Walrus
            The walrus is a large flippered marine mammal with a discontinuous circumpolar distribution in the Arctic Ocean and sub-Arctic seas of the Northern Hemisphere. The walrus is the only living species in the Odobenidae family and Odobenus genus. It is subdivided into three subspecies: the Atlantic...

            ; 1 species in 1 genus
          • Family Otariidae: sea lion
            Sea Lion
            Sea lions are pinnipeds characterized by external ear-flaps, long fore-flippers, the ability to walk on all fours, and short thick hair. Together with the fur seal, they comprise the family Otariidae, or eared seals. There are six extant and one extinct species in five genera...

            s, eared seal
            Eared Seal
            The eared seals or otariids are marine mammals in the family Otariidae, one of three groupings of Pinnipeds. They comprise 16 species in seven genera commonly known either as sea lions or fur seals, distinct from true seals and the Walrus...

            s, fur seal
            Fur seal
            Fur seals are any of nine species of pinnipeds in the Otariidae family. One species, the northern fur seal inhabits the North Pacific, while seven species in the Arctocephalus genus are found primarily in the Southern hemisphere...

            s; 14 species in 7 genera
          • Family Phocidae: true seals; 19 species in 9 genera

Phylogenetic Tree




External links