Order CarnivoraThe order carnivora includes over 260 species of placental mammals. Its members are formally referred to as carnivorans, while the word "carnivore" (often popularly applied to members of this group) can refer to any meat-eating animal, not just those that belong to this taxonomy order. The word carnivora comes from the Latin words carō (stem carn-) meaning "flesh", plus vorāre meaning "to devour".Carnivorans are the most diverse in size of any mammalian order, ranging from the Least Weasel (Mustela nivalis), at as little as 25 grams and 11 cm (4.3 in), to the Southern Elephant Seal whose adult males weigh up to 5000 kg (11,000 lbs) and measure 4.2 m (13.9 ft). Some carnivorans, such as cats, pinnipeds, and weasels, are almost completely carnivorous. Others, such as bears, are more omnivorous, although the Polar Bear is predominantly carnivorous, with 90% of its diet consisting of seals. The Giant Panda is almost exclusively an herbivore but occasionally eats fish, eggs and insects. Carnivorans have teeth and claws adapted for catching and eating other animals. Their eyes point forward. Many carnivorans hunt in packs and are social. 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 and caniformia). Carnivorans are primarily terrestrial (live on the surface of the land) and usually have strong sharp claws, with never less than four toes to each foot. 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.Carnivorans have well-developed prominent canine teeth and cheek 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 and the least developed in the Ursidae. Carnivorans have six incisors and two conical canines in each jaw. The only two exceptions to this are the Sea Otter (Enhydra lutris), which has four incisors in the lower jaw, and the Sloth Bear (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. Incisors are retained by carnivorans and the third incisor is commonly large and sharp (canine-like). 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 just behind the maxilla (common to all mammals), 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) 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 (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. 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, 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 the Canoidea. Carnivorans are excellent runners: some over long distances, but most are sprinters with high speeds over relatively short distances. Even bears and raccoons, although seemingly slow and clumsy, are capable of remarkable bursts of speed. Carnivorans include carnivores, omnivores, and even a few primarily herbivorous species, such as the Giant Panda. 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. Carnivora tend to produce a single litter annually, but some produce multiple litters a year, and larger carnivores like bears have gaps of 2-3 years between litters. The average gestation period lies between 50-115 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 carnivores are solitary, but a few are gregarious, and some, like wolves, have a highly developed social structure. TaxonavigationSuperregnum: Eukaryota
Regnum: Animalia
Subregnum: Eumetazoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclass: Tetrapoda
Class: Mammalia
Subclass: Theria
Infraclass: Placentalia
Order: Carnivora
Subordines: Caniformia - Feliformia - †Miacoidea ORDER CARNIVORA Suborder Feliformia ("cat-like") - Family †Stenoplesictidae
- Family †Percrocutidae
- Family †Nimravidae: false sabre-tooth cats (5–36 Ma)
- Family Nandiniidae: African Palm Civet; 1 species in 1 genus
Superfamily Feloidea - Family Prinonodontidae: Asiatic linsangs; 2 species in 1 genus
- Family †Barbourofelidae (6–18 Ma)
- Family Felidae: cats; 40 species in 14 genera
Infraorder Viverroidea - Family Viverridae: civets and allies; 35 species in 15 genera
Superfamily Herpestoidea - Family Hyaenidae: hyenas and Aardwolf; 4 species in 4 genera
- Family Eupleridae : Malagasy carnivores; 8 species in 7 genera
- Family Herpestidae: mongooses and allies; 33 species in 14 genera
Suborder Caniformia ("dog-like") - Family †Amphicyonidae: bear-dogs (9–37 Ma)
- Family Canidae: dogs and allies; 37 species in 10 genera
Infraorder Arctoidea Superfamily Ursoidea - Family †Hemicyonidae: (2-22 Ma)
- Family Ursidae: bears; 8 species in 5 genera
Superfamily Musteloidea - Family Ailuridae: Red Panda; 1 species in 1 genus.
- Family Mephitidae: skunks and stink badgers; 10 species in 4 genera
- Family Mustelidae: weasels, martens, badgers, wolverines, minks, and otters; 55 species in 24 genera
- Family Procyonidae: raccoons and allies; 19 species in 6 genera
Superfamily Pinnipedia - Family †Enaliarctidae: (23–20 Ma?)
- Family Odobenidae: Walrus; 1 species in 1 genus
- Family Otariidae: sea lions, eared seals, fur seals; 14 species in 7 genera
- Family Phocidae: true seals; 19 species in 9 genera
Phylogenetic Tree† = extinct | Carnivora | | Feliformia |
| Nimravidae† |
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| Stenoplesictidae† |
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| Nandiniidae |
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| | Caniformia |
| Amphicyonidae† |
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| Canidae |
| | Arctoidea | |
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