An apocrine sweat gland ( / ˈ æ p ə k r ə n , - ˌ k r aɪ n , - ˌ k r iː n / ; from Greek apo 'away' and krinein 'to separate') is composed of a coiled secretory portion located at the junction of the dermis and subcutaneous fat , from which a straight portion inserts and secretes into the infundibular portion of the hair follicle . In humans, apocrine sweat glands are found only in certain locations of the body: the axillae (armpits), areola and nipples of the breast, ear canal , eyelids , wings of the nostril , perineal region , and some parts of the external genitalia . Modified apocrine glands include the ciliary glands (glands of Moll) in the eyelids; the ceruminous glands , which produce ear wax ; and the mammary glands , which produce milk . They are distinct from eccrine sweat glands , which cover the whole body.
55-493: [REDACTED] Look up porker in Wiktionary, the free dictionary. Porker may refer to: Pig , particularly those fattened for eating An obese person Porsche motor cars, sometimes known as Porkers A lie , known by the slang term porkie pie or porker Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with
110-565: A pheromone , territorial marker, and warning signal . Being sensitive to adrenaline , apocrine sweat glands are involved in emotional sweating in humans (induced by anxiety, stress, fear, sexual stimulation, and pain). In a five-month-old human fetus, apocrine glands are distributed all over the body; after a few weeks, they exist in only restricted areas, including the armpits and external genitalia. They are inactive until stimulated by hormonal changes in puberty . The apocrine gland secretes an oily fluid with proteins and lipids that
165-495: 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
220-485: 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;
275-453: 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
330-534: 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
385-571: 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
440-685: 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
495-468: 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
550-403: 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
605-456: 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
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#1732802173345660-647: A smooth muscle lining around the secretory cells; when the muscles contract, they squeeze the secretory ducts and push out the accumulated fluid into the hair follicle. Sweat and sebum are mixed in the hair follicle and arrive mixed at the epidermal surface. The apocrine sweat is cloudy, viscous, initially odorless, and at a pH of 6–7.5. It contains water, protein, carbohydrate waste material, and NaCl . The sweat only attains its characteristic odor upon being degraded by bacteria, which releases volatile odor molecules. More bacteria (especially corynebacteria ) leads to stronger odor. The presence of axillary hair also makes
715-488: 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
770-414: 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
825-485: 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
880-499: 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
935-705: Is an omnivorous , domesticated , even-toed, hoofed mammal . It 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
990-475: 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
1045-420: 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
1100-429: Is made up of a glomerulus of secretory tubules and an excretory duct that opens into a hair follicle; on occasion, an excretory duct opens to the skin surface next to the hair. The gland is large and spongy, located in the subcutaneous fat deep in the dermis, and has a larger overall structure and lumen diameter than the eccrine sweat gland . The secretory tubules of apocrine glands are single layered, but unlike
1155-450: 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
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#17328021733451210-542: Is odorless before microbial activity. It appears on the skin surface mixed with sebum , as sebaceous glands open into the same hair follicle. Unlike eccrine sweat glands, which secrete continuously, the apocrine glands secrete in periodic spurts. Apocrine sweat glands were originally thought to use only apocrine secretion: vesicles pinch off from the secretory cells, then degrade in the secretory lumen, releasing their product. More recent research has shown that merocrine secretion also takes place. Myoepithelial cells form
1265-400: 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
1320-529: 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
1375-627: 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
1430-455: 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
1485-797: The 1983 film Trading Places . Trade in pork bellies declined, and they were delisted from the Chicago Mercantile Exchange in 2011. Apocrine sweat gland Most non-primate mammals, however, have apocrine sweat glands over the greater part of their body. Domestic animals such as dogs and cats have apocrine glands at each hair follicle and even in their urinary system, but eccrine glands only in foot pads and snout. Their apocrine glands, like those in humans, produce an odorless, oily, opaque secretion that gains its characteristic odor upon bacterial decomposition. Eccrine glands on their paws increase friction and prevent them from slipping when fleeing from danger. The apocrine gland
1540-484: 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
1595-623: 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
1650-553: 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
1705-414: 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
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1760-470: 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
1815-527: The eccrine secretory tubules, contain only a single type of ductal epithelial cell, varying in diameter according to their location, and sometimes branching off into multiple ducts. The tubules are wrapped in myoepithelial cells , which are more developed than in their eccrine gland counterparts. In hoofed animals and marsupials , apocrine glands act as the main thermoregulator , secreting watery sweat. For most mammals, however, apocrine sweat glands secrete an oily (and eventually smelly) compound that acts as
1870-457: 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
1925-417: 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
1980-416: 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
2035-464: 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
2090-446: 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
2145-483: 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
2200-461: 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,
2255-568: 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
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2310-432: 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
2365-399: 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
2420-443: 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
2475-405: 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
2530-431: 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
2585-411: The odor even more pungent, as secretions, debris, keratin , and bacteria accumulate on the hairs. Non-primate mammals usually have apocrine sweat glands over most of their bodies. Horses use them as a thermoregulatory device, as they are regulated by adrenaline and more widely distributed on equines than in other groups. Skunks , on the other hand, use the glands to release a secretion that acts as
2640-402: 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
2695-795: 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
2750-469: 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
2805-406: 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
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#17328021733452860-452: 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,
2915-516: The title Porker . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Porker&oldid=1255982630 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Pig The pig ( Sus domesticus ), also called swine ( pl. : swine) or hog ,
2970-498: 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
3025-650: 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
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