Dentition pertains to the development of teeth and their arrangement in the mouth . In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiology (that is, the relationship between the shape and form of the tooth in question and its inferred function) of the teeth of an animal.
99-535: Dicotylidae Peccaries (also javelinas or skunk pigs ) are pig -like ungulates of the family Tayassuidae (New World pigs). They are found throughout Central and South America , Trinidad in the Caribbean , and in the southwestern area of North America . Peccaries usually measure between 90 and 130 cm (2 ft 11 in and 4 ft 3 in) in length, and a full-grown adult usually weighs about 20 to 40 kg (44 to 88 lb). They represent
198-483: A pig . Like a pig, it has a snout ending in a cartilaginous disc and eyes that are small relative to its head. Also like a pig, it uses only the middle two digits for walking, although, unlike pigs, the other toes may be altogether absent. Its stomach is not ruminating . Though it has three chambers, it is more complex than those of pigs. Peccaries are foregut fermenters (pigs are hindgut fermenters ). This foregut fermentation, similar to but separately evolved from
297-495: A healthy, full-grown adult. Vietnamese Pot-bellied pigs, a miniature breed of pig , have been kept as pets in the United States, beginning in the latter half of the 20th century. Pigs are intelligent, social creatures. They are considered hypoallergenic and are known to do quite well with people who have the usual animal allergies. Since these animals are known to have a life expectancy of 15 to 20 years, they require
396-477: A higher age before they are able to give birth ( parturition ) and have a tendency towards infanticide . Recently established Brazilian boar populations are not to be confused with long-established populations of feral domestic pigs, which have existed mainly in the Pantanal for more than 100 years, along with native peccaries. The demographic dynamics of the interaction between feral pig populations and those of
495-485: A large head, with a long snout strengthened by a special prenasal bone and a disk of cartilage at the tip. The snout is used to dig into the soil to find food and is an acute sense organ. The dental formula of adult pigs is 3.1.4.3 3.1.4.3 , giving a total of 44 teeth . The rear teeth are adapted for crushing. In males, the canine teeth can form tusks , which grow continuously and are sharpened by grinding against each other. There are four hoofed toes on each foot;
594-401: A large surface area for the mechanical digestion of tough plant materials. This type of dental strategy is observed in ornithopod and ceratopsian dinosaurs as well as the duck-billed hadrosaurs , which had more than one hundred teeth in each dental battery . The teeth of carnivorous dinosaurs, called ziphodont, were typically blade-like or cone-shaped, curved, with serrated edges. This dentition
693-453: A litter of piglets, once per year. By the nineteenth century, European piglets routinely double-farrowed, or bore two litters of piglets per year. It is unclear when this shift occurred. Pigs have a maximum life span of about 27 years. A characteristic of pigs which they share with carnivores is nest-building . Sows root in the ground to create depressions the size of their body, and then build nest mounds, using twigs and leaves, softer in
792-475: A long row of pointed or sharp-sided, undifferentiated teeth ( homodont ) that are completely replaceable. The mammalian pattern is significantly different. The teeth in the upper and lower jaws in mammals have evolved a close-fitting relationship such that they operate together as a unit. "They 'occlude', that is, the chewing surfaces of the teeth are so constructed that the upper and lower teeth are able to fit precisely together, cutting, crushing, grinding or tearing
891-534: A long-term commitment. Given pigs are bred primarily as livestock and have not been bred as companion animals for very long, selective breeding for a placid or biddable temperament is not well established. Pigs have radically different psychology and behaviours compared to dogs, and exhibit fight-or-flight instincts, an independent nature, and natural assertiveness . Male and female swine that have not been de-sexed may express unwanted aggressive behavior, and are prone to developing serious health issues. As rooting
990-442: A niche similar to raccoons and other urban scavengers. In Arizona they are often called by their Spanish name "javelinas". Collared peccaries are generally found in bands of 8 to 15 animals of various ages. They defend themselves if they feel threatened, but otherwise tend to ignore humans. A second species, the white-lipped peccary ( Tayassu pecari ), is mainly found in rainforests of Central and South America, but also known from
1089-571: A now extinct ghost population of wild pigs during the Pleistocene . The genomes of domestic pigs show strong selection for genes affecting behavior and morphology. Human selection for domestic traits likely counteracted the homogenizing effect of gene flow from wild boars and created domestication islands in the genome. Pigs arrived in Europe from the Near East at least 8,500 years ago. Over
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#17327934911561188-420: A ruminant, is an example of convergent evolution . Peccaries are omnivores and will eat insects, grubs, and occasionally small animals, although their preferred foods consist of roots, grasses , seeds, fruit, and cacti —particularly prickly pear . Pigs and peccaries can be differentiated by a number of characteristic, including tails and ear shape. The ears of pigs are large and upright and often pointed while
1287-685: A separate species. Archaeological evidence shows that pigs were domesticated from wild boar in the Near East in or around the Tigris Basin, being managed in a semi-wild state much as they are managed by some modern New Guineans. There were pigs in Cyprus more than 11,400 years ago, introduced from the mainland, implying domestication in the adjacent mainland by then. Pigs were separately domesticated in China, starting some 8,000 years ago. In
1386-468: A short time and then sleep for a short time. Pigs are omnivorous and versatile in their feeding behaviour. They primarily eat leaves, stems, roots, fruits, and flowers. Rooting is an instinctual comforting behaviour in pigs characterized by nudging the snout into something. It first happens when piglets are born to obtain their mother's milk, and can become a habitual, obsessive behaviour, most prominent in animals weaned too early. Pigs root and dig into
1485-403: A shoulder height of 1.5 m (4 ft 11 in). Pigs possess both apocrine and eccrine sweat glands , although the latter are limited to the snout. Pigs, like other "hairless" mammals such as elephants, do not use thermal sweat glands in cooling. Pigs are less able than many other mammals to dissipate heat from wet mucous membranes in the mouth by panting. Their thermoneutral zone
1584-456: A simplified, crowded, or uncomfortable environment may resort to tail-biting ; farmers sometimes dock the tails of pigs to prevent the problem, or may enrich the environment with toys or other objects to reduce the risk. Because of their relative lack of sweat glands, pigs often control their body temperature using behavioural thermoregulation. Wallowing , coating the body with mud, is a common behaviour. They do not submerge completely under
1683-443: A single herd of white-lipped peccaries, but collared and Chacoan peccaries usually form smaller groups. Such social behavior seems to have been the situation in extinct peccaries as well. The giant peccary ( Pecari maximus ) of Brazil appears to be less social, primarily living in pairs. Peccaries rely on their social structure to defend territory, protect against predators, regulate temperature, and interact with other members of
1782-488: A target on screen. Pigs have panoramic vision of approximately 310° and binocular vision of 35° to 50°. It is thought they have no eye accommodation . Other animals that have no accommodation, e.g. sheep, lift their heads to see distant objects. The extent to which pigs have colour vision is still a source of some debate; however, the presence of cone cells in the retina with two distinct wavelength sensitivities (blue and green) suggests that at least some colour vision
1881-414: A teat, the more milk that teat later releases. In pigs, dominance hierarchies are formed at an early age. Piglets are precocious, and attempt to suckle soon after being born. The piglets are born with sharp teeth and fight for the anterior teats, as these produce more milk. Once established, this teat order remains stable; each piglet tends to feed on a particular teat or group of teats. Stimulation of
1980-478: A variety of tooth shapes is said to have heterodont dentition. An example of this are dinosaurs of the group Heterodontosauridae and the enigmatic early dinosaur, Eoraptor . While most dinosaurs had a single row of teeth on each side of their jaws, others had dental batteries where teeth in the cheek region were fused together to form compound teeth. Individually these teeth were not suitable for grinding food, but when joined together with other teeth they would form
2079-551: A well-attested fossil record , and numerous extinct genera are known: Although some taxa from the Old World like the European Miocene Taucanamo have been suggested to be members of Tayussidae, their assignation to the group is equivocal, with a 2017 phylogenetic analysis recovering Taucanamo outside the clade containing suids and peccaries. The oldest unambiguous fossils of peccaries are from
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#17327934911562178-491: A wide range of other habitats such as dry forests, grasslands, mangrove , cerrado , and dry xerophytic areas. The two main threats to their survival are deforestation and hunting. The third species, the Chacoan peccary ( Catagonus wagneri ). It is found in the dry shrub habitat or Chaco of Paraguay , Bolivia , and Argentina . The Chacoan peccary has the distinction of having been first described based on fossils and
2277-485: A year, usually in spring or early summer, to prepare for the warmer months ahead. Where pigs are allowed to roam freely, they walk roughly 4 km daily, scavenging within a home range of around a hectare. Farmers in Africa often choose such a low-input, free-range production system. If conditions permit, pigs feed continuously for many hours and then sleep for many hours, in contrast to ruminants , which tend to feed for
2376-499: Is 16–22 °C (61–72 °F). At higher temperatures, pigs lose heat by wallowing in mud or water via evaporative cooling, although it has been suggested that wallowing may serve other functions, such as protection from sunburn, ecto-parasite control, and scent-marking. Pigs are among four mammalian species with mutations in the nicotinic acetylcholine receptor that protect against snake venom . Mongooses , honey badgers , hedgehogs , and pigs all have different modifications to
2475-442: Is also present in crocodilians and mammals , but is not found among the non- archosaur reptiles, which instead have acrodont or pleurodont dentition. Teeth that were lost were replaced by teeth below the roots in each tooth socket. Occlusion refers to the closing of the dinosaur's mouth, where the teeth from the upper and lower parts of the jaw meet. If the occlusion causes teeth from the maxillary or premaxillary bones to cover
2574-423: Is an important area of study for archaeologists, especially those specializing in the study of older remains. Dentition affords many advantages over studying the rest of the skeleton itself ( osteometry ). The structure and arrangement of teeth is constant and, although it is inherited, does not undergo extensive change during environmental change, dietary specializations, or alterations in use patterns. The rest of
2673-518: Is called javelina , jabalí (a word also used to describe wild boar ), sajino , or pecarí . The word javelina derives from the Spanish word for "wild boar". In French Guiana and Suriname , the animal is called pakira . The scientific name Tayassuidae derives from the same source as the Portuguese tajaçu . A peccary is a medium-sized animal, with a strong resemblance to
2772-660: Is called a squadron. A squadron of peccaries averages between six and nine members. Peccaries first appeared in North America during the Miocene and migrated into South America during the Pliocene – Pleistocene as part of the Great American Interchange . They are often confused with feral domestic pigs , commonly known as "razorback" hogs in many parts of the United States, when the two occur in
2871-569: Is directed by the shape of the teeth in contact and the Glenoid Fossa/Condyle shape. The outer extremities of this envelope are limited by muscles, ligaments and the articular disc of the TMJ. Without the guidance of anterior incisors and canines, this envelope of function can be destructive to the remaining teeth resulting in periodontal trauma from occlusion seen as wear, fracture or tooth loosening and loss. The premolars and molars are at
2970-528: Is disagreement regarding whether the third type of deciduous tooth is a premolar (the general consensus among mammalogists) or a molar (commonly held among human anatomists). There is thus some discrepancy between nomenclature in zoology and in dentistry. This is because the terms of human dentistry, which have generally prevailed over time, have not included mammalian dental evolutionary theory. There were originally four premolars in each quadrant of early mammalian jaws. However, all living primates have lost at least
3069-475: Is especially an issue in southeastern South America. Female pigs reach sexual maturity at 3–12 months of age and come into estrus every 18–24 days if they are not successfully bred. The variation in ovulation rate can be attributed to intrinsic factors such as age and genotype, as well as extrinsic factors like nutrition, environment, and the supplementation of exogenous hormones. The gestation period averages 112–120 days. Estrus lasts two to three days, and
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3168-420: Is found to be comforting, pigs kept in the house may root household objects, furniture or surfaces. Pet pigs should be let outside to allow them to fulfill their natural desire of rooting around. Approximately 1.5 billion pigs are slaughtered each year for meat. The pork belly futures contract became an icon of commodities trading . It appears in depictions of the arena in popular entertainment, such as
3267-450: Is most often considered to be a subspecies of the wild boar , which was given the name Sus scrofa by Carl Linnaeus in 1758; following from this, the formal name of the pig is Sus scrofa domesticus . However, in 1777, Johann Christian Polycarp Erxleben classified the pig as a separate species from the wild boar. He gave it the name Sus domesticus , still used by some taxonomists. The American Society of Mammalogists considers it
3366-638: Is named the domestic pig when distinguishing it from other members of the genus Sus . It is considered a subspecies of Sus scrofa (the wild boar or Eurasian boar) by some authorities, but as a distinct species by others. Pigs were domesticated in the Neolithic , both in East Asia and in the Near East. When domesticated pigs arrived in Europe, they extensively interbred with wild boar but retained their domesticated features. Pigs are farmed primarily for meat, called pork . The animal's skin or hide
3465-400: Is present. Pigs have a well-developed sense of smell; this is exploited in Europe where trained pigs find underground truffles . Pigs have 1,113 genes for smell receptors, compared to 1,094 in dogs; this may indicate an acute sense of smell, but against this, insects have only around 50 to 100 such genes but make extensive use of olfaction. Olfactory rather than visual stimuli are used in
3564-533: Is referred to as diphyodont , while the dentition of animals with only one set of teeth throughout life is monophyodont . The dentition of animals in which the teeth are continuously discarded and replaced throughout life is termed polyphyodont . The dentition of animals in which the teeth are set in sockets in the jawbones is termed thecodont . The evolutionary origin of the vertebrate dentition remains contentious. Current theories suggest either an "outside-in" or "inside-out" evolutionary origin to teeth, with
3663-481: Is strong enough to be detected by humans, which earns the peccary the nickname of "skunk pig". Three (possibly four) living species of peccaries are found from the Southwestern United States through Central America and into South America and Trinidad , each in their own genus. The collared peccary ( Dicotyles tajacu ) or "musk hog", referring to the animal's scent glands, occurs from
3762-529: Is used for leather . China is the world's largest pork producer, followed by the European Union and then the United States. Around 1.5 billion pigs are raised each year, producing some 120 million tonnes of meat, often cured as bacon . Some are kept as pets . Pigs have featured in human culture since Neolithic times, appearing in art and literature for children and adults, and celebrated in cities such as Bologna for their meat products. The pig has
3861-416: Is well-adapted to habitat disturbed by humans, merely requiring sufficient cover. They can be found in cities and agricultural land throughout their range. Notable populations exist in the suburbs of Phoenix and Tucson, Arizona , where they feed on ornamental plants and other cultivated vegetation . There are also urban populations as far north as Sedona, Arizona , where they have been known to fill
3960-627: The Midwest , where many state agencies have programs to remove them. Feral pigs in New Zealand and northern Queensland have caused substantial environmental damage. Feral hybrids of the European wild boar with the domestic pig are disruptive to both environment and agriculture, as they destroy crops, spread animal diseases including Foot-and-mouth disease , and consume wildlife such as juvenile seabirds and young tortoises . Feral pig damage
4059-449: The Southwestern United States into South America and the island of Trinidad. The coat consists of wiry peppered black, gray, and brown hair with a lighter colored "collar" circling the shoulders. They bear young year-round, but most often between November and March, with the average litter size consisting of two to three offspring. They are found in many habitats, from arid scrublands to humid tropical rain forests . The collared peccary
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4158-401: The dental eruption sequence . Rapidly developing anthropoid primates such as macaques , chimpanzees , and australopithecines have an eruption sequence of M1 I1 I2 M2 P3 P4 C M3, whereas anatomically modern humans have the sequence M1 I1 I2 C P3 P4 M2 M3. The later that tooth emergence begins, the earlier the anterior teeth (I1–P4) appear in the sequence. Dentition, or the study of teeth,
4257-523: The ground sloths and opossums , migrated north. Several species of peccary across the genera Platygonus and Mylohyus remained in North America until their extinction following the colonization of the continent by humans via Beringia at the end of the Pleistocene. Today, 2 of the 3 species are relegated to the Neotropical realm , but the collared peccary ranges into northern Mexico and
4356-455: The tick -borne African Swine Fever , bacterial infections such as Clostridium , arthritis caused by Mycoplasma , and stillbirths caused by Parvovirus . Some parasites of pigs are a public health risk as they can be transmitted to humans in undercooked pork. These are the pork tapeworm Taenia solium ; a protozoan, Toxoplasma gondii ; and a nematode, Trichinella spiralis . Transmission can be prevented by thorough sanitation on
4455-541: The 1983 film Trading Places . Trade in pork bellies declined, and they were delisted from the Chicago Mercantile Exchange in 2011. Dentition Animals whose teeth are all of the same type, such as most non-mammalian vertebrates, are said to have homodont dentition, whereas those whose teeth differ morphologically are said to have heterodont dentition. The dentition of animals with two successions of teeth ( deciduous , permanent )
4554-849: The Early Miocene of North America, with the North American Eocene-Oligocene genus Perchoerus , also often considered an early peccary, recovered outside the clade containing peccaries and suids. Although common in South America today, peccaries did not reach there until about three million years ago during the Great American Interchange , when the Isthmus of Panama formed, connecting North America and South America. At that time, many North American animals—including peccaries, llamas and tapirs —entered South America, while some South American species, such as
4653-484: The Near East, pig husbandry spread for the next few millennia. It reduced gradually during the Bronze Age , as rural populations instead focused on commodity-producing livestock, but it was sustained in cities. Domestication did not involve reproductive isolation with population bottlenecks. Western Asian pigs were introduced into Europe, where they crossed with wild boar. There appears to have been interbreeding with
4752-568: The Near Eastern genes dying out in European pig stock. More recently there have been complex exchanges, with European domesticated lines being exported, in turn, to the ancient Near East. Historical records indicate that Asian pigs were again introduced into Europe during the 18th and early 19th centuries. Among the animals that the Spanish introduced to the Chiloé Archipelago in the 16th century Columbian Exchange , pigs were
4851-721: The Yucatán, Panama, the southern Caribbean, and Colombia at the time of the Conquest . Archaeological remains of peccaries have been found in Mesoamerica from the Preclassic (or Formative) period up until immediately before Spanish contact. Specifically, peccary remains have been found at Early Formative Olmec civilization sites. The peccary is not readily suitable for modern captive breeding, lacking suitable characteristics for intensive or semi-intensive systems. Peccaries require
4950-407: The animal's upper jaw. The dentary is the main bone that forms the lower jaw (mandible). The predentary is a smaller bone that forms the anterior end of the lower jaw in ornithischian dinosaurs; it is always edentulous and supported a horny beak. Unlike modern lizards, dinosaur teeth grew individually in the sockets of the jawbones, which are known as the dental alveoli . This thecodont dentition
5049-553: The anterior teats appears to be important in causing milk letdown, so it might be advantageous to the entire litter to have these teats occupied by healthy piglets. Piglets locate teats by sight and then by olfaction. Pig behaviour is intermediate between that of other artiodactyls and of carnivores . Pigs seek out the company of other pigs and often huddle to maintain physical contact, but they do not naturally form large herds. They live in groups of about 8–10 adult sows, some young individuals, and some single males. Pigs confined in
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#17327934911565148-510: The back of the mouth. Depending on the particular mammal and its diet, these two kinds of teeth prepare pieces of food to be swallowed by grinding, shearing, or crushing. The specialised teeth—incisors, canines, premolars, and molars—are found in the same order in every mammal. In many mammals, the infants have a set of teeth that fall out and are replaced by adult teeth . These are called deciduous teeth , primary teeth, baby teeth or milk teeth. Animals that have two sets of teeth, one followed by
5247-414: The boar's corkscrew-shaped penis during copulation. Females have bicornuate uteruses and two conceptuses must be present in both uterine horns to enable pregnancy to proceed. The mother's body recognises that it is pregnant on days 11 to 12 of pregnancy, and is marked by the corpus luteum 's producing the sex hormone progesterone . To sustain the pregnancy, the embryo signals to the corpus luteum with
5346-434: The closest relatives of the family Suidae , which contains pigs and relatives. Together Tayassuidae and Suidae are grouped in the suborder Suina within the order Artiodactyla ( even-toed ungulates ). Peccaries are social creatures that live in herds. They are omnivores and eat roots, grubs, and a variety of other foods. They can identify each other by their strong odors. A group of peccaries that travel and live together
5445-526: The collared peccary has later been questioned, leading the IUCN to treat it as a synonym . During the Late Pleistocene , two extinct peccaries, Mylohyus and Platygonus , were widespread across North America (and in the case of Platygonus , South America), but became extinct at the end of the Pleistocene around 12,000 years ago following the arrival of humans. In addition, Tayassuidae have
5544-437: The dentition arising from odontodes on the skin surface moving into the mouth, or vice versa. Despite this debate, it is accepted that vertebrate teeth are homologous to the dermal denticles found on the skin of basal Gnathostomes (i.e. Chondrichtyans). Since the origin of teeth some 450 mya, the vertebrate dentition has diversified within the reptiles , amphibians , and fish : however most of these groups continue to possess
5643-470: The domesticated pig is one of the most numerous large mammals on the planet. Like all animals, pigs are susceptible to adverse impacts from climate change , such as heat stress from increased annual temperatures and more intense heatwaves . Heat stress has increased rapidly between 1981 and 2017 on pig farms in Europe. Installing a ground-coupled heat exchanger is an effective intervention. Around 600 breeds of pig have been created by farmers around
5742-418: The ears of peccaries are small and rounded. Pigs also have tasseled tails, but peccaries' tails are small and discreet. The most noticeable difference between pigs and peccaries is the shape of the canine teeth, or tusks . In European pigs, the tusks are long and curve around on themselves, whereas in peccaries, the tusks are short and straight and interlock with each other, prohibiting side-to-side movement of
5841-457: The farm; by meat inspection and careful commercial processing; and by thorough cooking, or alternatively by sufficient freezing and curing. Pigs have been raised outdoors, and sometimes allowed to forage in woods or pastures. In industrialized nations, pig production has largely switched to large-scale intensive pig farming . This has lowered production costs but has caused concern about possible cruelty . As consumers have become concerned with
5940-417: The female's displayed receptiveness to mate is known as standing heat. Standing heat is a reflexive response that is stimulated when the female is in contact with the saliva of a sexually mature boar. Androstenol is one of the pheromones produced in the submaxillary salivary glands of boars that trigger the female's response. The female cervix contains a series of five interdigitating pads, or folds, that hold
6039-405: The first premolar. "Hence most of the prosimians and platyrrhines have three premolars. Some genera have also lost more than one. A second premolar has been lost in all catarrhines. The remaining permanent premolars are then properly identified as P2, P3 and P4 or P3 and P4; however, traditional dentistry refers to them as P1 and P2". The order in which teeth emerge through the gums is known as
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#17327934911566138-416: The flow stops and so does the grunting of the sow. The piglets may dart from teat to teat and recommence suckling with slow movements, or nosing the udder. Piglets massage and suckle the sow's teats after milk flow ceases as a way of letting the sow know their nutritional status. This helps her to regulate the amount of milk released from that teat in future sucklings. The more intense the post-feed massaging of
6237-428: The following formulae show the deciduous and usual permanent dentition of all catarrhine primates , including humans: The greatest number of teeth in any known placental land mammal was 48, with a formula of 3.1.5.3 3.1.5.3 . However, no living placental mammal has this number. In extant placental mammals, the maximum dental formula is 3.1.4.3 3.1.4.3 for pigs. Mammalian tooth counts are usually identical in
6336-470: The food caught between." Mammals have up to four distinct types of teeth, though not all types are present in all mammals. These are the incisor ( cutting ), the canine , the premolar , and the molar ( grinding ). The incisors occupy the front of the tooth row in both upper and lower jaws. They are normally flat, chisel-shaped teeth that meet in an edge-to-edge bite. Their function is cutting, slicing, or gnawing food into manageable pieces that fit into
6435-463: The formula 2.1.2.3 for upper teeth indicates 2 incisors, 1 canine, 2 premolars, and 3 molars on one side of the upper mouth. The deciduous dental formula is notated in lowercase lettering preceded by the letter d: for example: di:dc:dp. An animal's dentition for either deciduous or permanent teeth can thus be expressed as a dental formula, written in the form of a fraction, which can be written as I.C.P.M I.C.P.M , or I.C.P.M / I.C.P.M. For example,
6534-464: The ground to forage for food. Rooting is also a means of communication. Pigs are relatively intelligent animals, roughly on par with dogs . They distinguish each other as individuals, spend time in play, and form structured communities. They have good long-term memory and they experience emotions, changing their behaviour in response to the emotional states of other pigs. In terms of experimental tasks, pigs can perform tasks that require them to identify
6633-446: The herd. This ensures they do not get trampled on, and prevents other piglets from stealing milk from the sow. The onset of nest-building is triggered by a rise in prolactin level, caused by a decrease in progesterone and an increase in prostaglandin; the gathering of nest material seems to be regulated more by external stimuli such as temperature. Pigs have complex nursing and suckling behaviour. Nursing occurs every 50–60 minutes, and
6732-483: The hormones estradiol and prostaglandin E2 . This signaling acts on both the endometrium and luteal tissue to prevent the regression of the corpus luteum by activation of genes that are responsible for corpus luteum maintenance. During mid to late pregnancy, the corpus luteum relies primarily on luteinizing hormone for maintenance until birth. Archeological evidence indicates that medieval European pigs farrowed, or bore
6831-461: The humane treatment of livestock, demand for pasture-raised pork in these nations has increased. Most pigs in the US receive ractopamine , a beta-agonist drug , which promotes muscle instead of fat and quicker weight gain, requiring less feed to reach finishing weight, and producing less manure . China has requested that pork exports be ractopamine-free. With a population of around 1 billion individuals,
6930-568: The identification of other pigs. Hearing is well developed; sounds are localised by moving the head. Pigs use auditory stimuli extensively for communication in all social activities. Alarm or aversive stimuli are transmitted to other pigs not only by auditory cues but also by pheromones . Similarly, recognition between the sow and her piglets is by olfactory and vocal cues. Pigs are subject to many pests and diseases which can seriously affect productivity and cause death. These include parasites such as Ascaris roundworms, virus diseases such as
7029-466: The jaw forwards and backwards (protrusion/retrusion). The canines come into function guiding the vertical movement when the chewing is side to side (lateral). The canines alone can cause the other teeth to separate at the extreme end of the cycle (cuspid guided function) or all the posterior teeth can continue to stay in contact (group function). The entire range of this movement is the envelope of masticatory function. The initial movement inside this envelope
7128-439: The jaw. The jaws and tusks of peccaries are adapted for crushing hard seeds and slicing into plant roots, and they also use their tusks to defend against predators. The dental formula for peccaries is: 2.1.3.3 3.1.3.3 By rubbing the tusks together, they can make a chattering noise that warns potential predators to stay away. Peccaries are social animals , often forming herds . Over 100 individuals have been recorded for
7227-402: The local Tupi people as caitetu munde , which means "great peccary which lives in pairs". Thought to be the largest extant peccary, it can grow to 1.2 m (4 ft) in length. Its pelage is completely dark gray, with no collars whatsoever. Unlike other peccaries, it lives in pairs, or with one or two offspring. However, the scientific evidence for considering it as a species separate from
7326-432: The locations of objects; they can solve mazes; and they can work with a simple language of symbols. They display self-recognition in a mirror . Pigs have been trained to associate different sorts of music (Bach and a military march) with food and social isolation respectively, and could communicate the resulting positive or negative emotion to untrained pigs. Pigs can be trained to use a joystick with their snout to select
7425-409: The maxillary teeth in a particular movement that is harmonious to the shape of the occluding surfaces. This creates the incising and grinding functions. The teeth must mesh together the way gears mesh in a transmission. If the interdigitation of the opposing cusps and incisal edges are not directed properly the teeth will wear abnormally (attrition), break away irregular crystalline enamel structures from
7524-399: The middle, in which to give birth. When the mound reaches the desired height, she places large branches, up to 2 metres in length, on the surface. She enters the mound and roots around to create a depression within the gathered material. She then gives birth in a lying position, unlike other artiodactyls which usually stand while birthing. Nest-building occurs during the last 24 hours before
7623-443: The most successful in adapting to local conditions. The pigs benefited from abundant shellfish and algae exposed by the large tides of the archipelago. Pigs were brought to southeastern North America from Europe by de Soto and other early Spanish explorers . Escaped pigs became feral . Pigs have escaped from farms and gone feral in many parts of the world. Feral pigs in the southeastern United States have migrated north to
7722-481: The mouth for further chewing. The canines are immediately behind the incisors. In many mammals, the canines are pointed, tusk-shaped teeth, projecting beyond the level of the other teeth. In carnivores, they are primarily offensive weapons for bringing down prey. In other mammals such as some primates, they are used to split open hard-surfaced food. In humans, the canine teeth are the main components in occlusal function and articulation. The mandibular teeth function against
7821-405: The mud, but vary the depth and duration of wallowing depending on environmental conditions. Adult pigs start wallowing once the ambient temperature is around 17–21 °C (63–70 °F). They cover themselves in mud from head to tail. They may use mud as a sunscreen, or to keep parasites away. Most bristled pigs "blow their coat", meaning that they shed most of the longer, coarser stiff hair once
7920-431: The next 3,000 years they interbred with European wild boar until their genome showed less than 5% Near Eastern ancestry, yet retained their domesticated features. DNA evidence from subfossil remains of teeth and jawbones of Neolithic pigs shows that the first domestic pigs in Europe were brought from the Near East. This stimulated the domestication of local European wild boar, resulting in a third domestication event with
8019-465: The number and type of teeth and in the shape and size of the chewing surface. The number of teeth of each type is written as a dental formula for one side of the mouth, or quadrant , with the upper and lower teeth shown on separate rows. The number of teeth in a mouth is twice that listed, as there are two sides. In each set, incisors (I) are indicated first, canines (C) second, premolars (P) third, and finally molars (M), giving I:C:P:M. So for example,
8118-402: The onset of farrowing, and becomes most intense 12 to 6 hours before farrowing. The sow separates from the group and seeks a suitable nest site with well-drained soil and shelter from rain and wind. This provides the offspring with shelter, comfort, and thermoregulation. The nest provides protection against weather and predators, while keeping the piglets close to the sow and away from the rest of
8217-516: The other, are said to be diphyodont. Normally the dental formula for milk teeth is the same as for adult teeth except that the molars are missing. Because every mammal's teeth are specialised for different functions, many mammal groups have lost the teeth that are not needed in their adaptation. Tooth form has also undergone evolutionary modification as a result of natural selection for specialised feeding or other adaptations. Over time, different mammal groups have evolved distinct dental features, both in
8316-795: The receptor pocket which prevents α-neurotoxin from binding. Pigs have small lungs for their body size, and are thus more susceptible than other domesticated animals to fatal bronchitis and pneumonia . The genome of the pig has been sequenced; it contains about 22,342 protein -coding genes . Domestic pigs are related to other pig species as shown in the cladogram , based on phylogenetic analysis using mitochondrial DNA . Babirusa [REDACTED] Red river hog [REDACTED] Warthogs [REDACTED] Visayan warty pig [REDACTED] Philippine warty pig [REDACTED] Bornean bearded pig [REDACTED] Javan warty pig [REDACTED] [REDACTED] East Asian pigs [REDACTED] European pigs [REDACTED] The pig
8415-584: The skeleton is much more likely to exhibit change because of adaptation. Teeth also preserve better than bone, and so the sample of teeth available to archaeologists is much more extensive and therefore more representative. Dentition is particularly useful in tracking ancient populations' movements, because there are differences in the shapes of incisors, the number of grooves on molars, presence/absence of wisdom teeth, and extra cusps on particular teeth. These differences can not only be associated with different populations across space, but also change over time so that
8514-565: The southwestern United States. Peccaries bear a familial resemblance to true pigs due to their common ancestry, and are in the same suborder as swine ( Suina ). They have been present in South America since prehistoric times. The earliest scientific description of peccaries in the New World is in Brazil in 1547 and referred to them as "wild pigs". It has been documented that peccaries were tamed, penned, and raised for food and ritual purposes in
8613-469: The sow grunts at slow, regular intervals. Each series of grunts varies in frequency, tone and magnitude, indicating the stages of nursing to the piglets. The phase of competition for teats and of nosing the udder lasts for about a minute, ending when milk begins to flow. The piglets then hold the teats in their mouths and suck with slow mouth movements (one per second), and the rate of the sow's grunting increases for approximately 20 seconds. The grunt peak in
8712-406: The sow requires stimulation from piglets before milk let-down. Sensory inputs (vocalisation, odours from mammary and birth fluids, and hair patterns of the sow) are particularly important immediately post-birth to facilitate teat location by the piglets. Initially, the piglets compete for position at the udder; then the piglets massage around their respective teats with their snouts, during which time
8811-458: The species. Peccaries have scent glands below each eye and another on their backs, though these are believed to be rudimentary in P. maximus . They use the scent to mark herd territories, which range from 30 to 280 hectares (75 to 700 acres). They also mark other herd members with these scent glands by rubbing one against another. The pungent odor allows peccaries to recognize other members of their herd, despite their myopic vision. The odor
8910-404: The study of the characteristics of teeth could say which population one is dealing with, and at what point in that population's history they are. A dinosaur's dentition included all the teeth in its jawbones, which consist of the dentary , maxillary , and in some cases the premaxillary bones. The maxilla is the main bone of the upper jaw. The premaxilla is a smaller bone forming the anterior of
9009-418: The surface (abrasion), or fracture larger pieces (abfraction). This is a three-dimensional movement of the mandible in relation to the maxilla. There are three points of guidance: the two posterior points provided by the temporomandibular joints and the anterior component provided by the incisors and canines. The incisors mostly control the vertical opening of the chewing cycle when the muscles of mastication move
9108-459: The teeth of the dentary and predentary, the dinosaur is said to have an overbite, the most common condition in this group. The opposite condition is considered to be an underbite, which is rare in theropod dinosaurs. The majority of dinosaurs had teeth that were similarly shaped throughout their jaws but varied in size. Dinosaur tooth shapes included cylindrical, peg-like, teardrop-shaped, leaf-like, diamond-shaped and blade-like. A dinosaur that has
9207-452: The third phase of suckling does not coincide with milk ejection, but rather the release of oxytocin from the pituitary into the bloodstream. Phase four coincides with the period of main milk flow (10–20 seconds) when the piglets suddenly withdraw slightly from the udder and start sucking with rapid mouth movements of about three per second. The sow grunts rapidly, lower in tone and often in quick runs of three or four, during this phase. Finally,
9306-498: The two larger central toes bear most of the weight, while the outer two are also used in soft ground. Most pigs have rather sparsely bristled hair on their skin, though there are some woolly -coated breeds such as the Mangalitsa . Adult pigs generally weigh between 140 and 300 kg (310 and 660 lb), though some breeds can exceed this range. Exceptionally, a pig called Big Bill weighed 1,157 kg (2,551 lb) and had
9405-451: The two native species of peccaries ( collared peccary and white-lipped peccary ) is obscure and is still being studied. The existence of feral pigs could somewhat ease jaguar predation on peccary populations, as jaguars show a preference for hunting pigs when they are available. Pig The pig ( Sus domesticus ), also called swine ( pl. : swine) or hog , is an omnivorous , domesticated , even-toed, hoofed mammal . It
9504-459: The upper and lower jaws, but not always. For example, the aye-aye has a formula of 1.0.1.3 1.0.0.3 , demonstrating the need for both upper and lower quadrant counts. Teeth are numbered starting at 1 in each group. Thus the human teeth are I1, I2, C1, P3, P4, M1, M2, and M3. (See next paragraph for premolar naming etymology.) In humans, the third molar is known as the wisdom tooth , whether or not it has erupted. Regarding premolars, there
9603-506: The wild in similar ranges . The Maya kept herds of peccaries, using them in rituals and for food. They are kept as pets in many countries in addition to being raised on farms as a source of food. The word peccary is derived from the Carib word pakira or paquira . In Portuguese , a peccary is called pecari , porco-do-mato , queixada , tajaçu , among other names like Cateto or Caititu . In Spanish , it
9702-650: The world, mainly in Europe and Asia, differing in coloration, shape, and size. According to The Livestock Conservancy , as of 2016, three breeds of pig are critically rare (having a global population of fewer than 2000). They are the Choctaw hog , the Mulefoot , and the Ossabaw Island hog . The smallest known pig breed in the world is the Göttingen minipig , typically weighing about 26 kilograms (57 lb) as
9801-527: Was originally thought to be an extinct species. In 1975, the animal was discovered in the Chaco region of Paraguay . The species was well known to the native people. A fourth as yet unconfirmed species, the giant peccary ( Dicotyles maximus ), was described from the Brazilian Amazon and north Bolivia by Dutch biologist Marc van Roosmalen . Though relatively recently discovered, it has been known to
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