Wild boar, Wild swine, Common wild pig, Eurasian wild pig, Wild pig
The wild boar (Sus scrofa ), also known as the wild swine, common wild pig, Eurasian wild pig, or simply wild pig, is a suid native to much of Eurasia and North Africa, and has been introduced to the Americas and Oceania. The species is now one of the widest-ranging mammals in the world, as well as the most widespread suiform. It has been assessed as least concern on the IUCN Red List due to its wide range, high numbers, and adaptability to a diversity of habitats. It has become an invasive species in part of its introduced range. Wild boars probably originated in Southeast Asia during the Early Pleistocene and outcompeted other suid species as they spread throughout the Old World.
As of 1990, up to 16 subspecies are recognized, which are divided into four regional groupings based on skull height and lacrimal bone length. The species lives in matriarchal societies consisting of interrelated females and their young (both male and female). Fully grown males are usually solitary outside the breeding season. The wolf is the wild boar's main predator in most of its natural range except in the Far East and the Lesser Sunda Islands, where it is replaced by the tiger and Komodo dragon respectively. The wild boar has a long history of association with humans, having been the ancestor of most domestic pig breeds and a big-game animal for millennia. Boars have also re-hybridized in recent decades with feral pigs; these boar–pig hybrids have become a serious pest wild animal in the Americas and Australia.
The wild boar features prominently in the cultures of Indo-European people, many of which saw the animal as embodying warrior virtues. Cultures throughout Europe and Asia Minor saw the killing of a boar as proof of one's valor and strength. Neolithic hunter gatherers depicted reliefs of ferocious wild boars on their temple pillars at Göbekli Tepe some 11,600 years ago. Virtually all heroes in Greek mythology fight or kill a boar at one point. The demigod Herakles' third labour involves the capture of the Erymanthian Boar, Theseus slays the wild sow Phaea, and a disguised Odysseus is recognised by his handmaiden Eurycleia by the scars inflicted on him by a boar during a hunt in his youth. To the mythical Hyperboreans, the boar represented spiritual authority. Several Greek myths use the boar as a symbol of darkness, death and winter. One example is the story of the youthful Adonis, who is killed by a boar and is permitted by Zeus to depart from Hades only during the spring and summer period. This theme also occurs in Irish and Egyptian mythology, where the animal is explicitly linked to the month of October, therefore autumn. This association likely arose from aspects of the boar's actual nature. Its dark colour was linked to the night, while its solitary habits, proclivity to consume crops and nocturnal nature were associated with evil. The foundation myth of Ephesus has the city being built over the site where Prince Androklos of Athens killed a boar. Boars were frequently depicted on Greek funerary monuments alongside lions, representing gallant losers who have finally met their match, as opposed to victorious hunters as lions are. The theme of the doomed, yet valorous boar warrior also occurred in Hittite culture, where it was traditional to sacrifice a boar alongside a dog and a prisoner of war after a military defeat.
The boar as a warrior also appears in Germanic cultures, with its image having been frequently engraved on shields and swords. They also feature on Germanic boar helmets, such as the Benty Grange helmet, where it was believed to offer protection to the wearer and has been theorised to have been used in spiritual transformations into swine, similar to berserkers. The boar features heavily in religious practice in Germanic paganism where it is closely associated with Freyr and has also been suggested to have been a totemic animal to the Swedes, especially to the Yngling royal dynasty who claimed descent from the god.
According to Tacitus, the Baltic Aesti featured boars on their helmets and may have also worn boar masks. The boar and pig were held in particularly high esteem by the Celts, who considered them to be their most important sacred animal. Some Celtic deities linked to boars include Moccus and Veteris. It has been suggested that some early myths surrounding the Welsh hero Culhwch involved the character being the son of a boar god. Nevertheless, the importance of the boar as a culinary item among Celtic tribes may have been exaggerated in popular culture by the Asterix series, as wild boar bones are rare among Celtic archaeological sites and the few that do occur show no signs of butchery, having probably been used in sacrificial rituals.
The boar also appears in Vedic mythology and Hindu mythology. A story present in the Brahmanas has the god Indra slaying an avaricious boar, who has stolen the treasure of the asuras, then giving its carcass to the god Vishnu, who offered it as a sacrifice to the gods. In the story's retelling in the Charaka Samhita, the boar is described as a form of Prajapati and is credited with having raised the Earth from the primeval waters. In the Ramayana and the Puranas, the same boar is portrayed as Varaha, an avatar of Vishnu.
In Japanese culture, the boar is widely seen as a fearsome and reckless animal, to the point that several words and expressions in Japanese referring to recklessness include references to boars. The boar is the last animal of the Oriental zodiac, with people born during the year of the Pig being said to embody the boar-like traits of determination and impetuosity. Among Japanese hunters, the boar's courage and defiance is a source of admiration and it is not uncommon for hunters and mountain people to name their sons after the animal inoshishi (猪). Boars are also seen as symbols of fertility and prosperity; in some regions, it is thought that boars are drawn to fields owned by families including pregnant women, and hunters with pregnant wives are thought to have greater chances of success when boar hunting. The animal's link to prosperity was illustrated by its inclusion on the ¥10 note during the Meiji period and it was once believed that a man could become wealthy by keeping a clump of boar hair in his wallet.
In the folklore of the Mongol Altai Uriankhai tribe, the wild boar was associated with the watery underworld, as it was thought that the spirits of the dead entered the animal's head, to be ultimately transported to the water. Prior to the conversion to Islam, the Kyrgyz people believed that they were descended from boars and thus did not eat pork. In Buryat mythology, the forefathers of the Buryats descended from heaven and were nourished by a boar. In China, the boar is the emblem of the Miao people.
The boar (sanglier) is frequently displayed in English, Scottish and Welsh heraldry. As with the lion, the boar is often shown as armed and langued. As with the bear, Scottish and Welsh heraldry displays the boar's head with the neck cropped, unlike the English version, which retains the neck. The white boar served as the badge of King Richard III of England, who distributed it among his northern retainers during his tenure as Duke of Gloucester.
The wild boar is a bulky, massively built suid with short and relatively thin legs. The trunk is short and robust, while the hindquarters are comparatively underdeveloped. The region behind the shoulder blades rises into a hump and the neck is short and thick to the point of being nearly immobile. The animal's head is very large, taking up to one-third of the body's entire length. The structure of the head is well suited for digging. The head acts as a plough, while the powerful neck muscles allow the animal to upturn considerable amounts of soil: it is capable of digging 8–10 cm (3.1–3.9 in) into frozen ground and can upturn rocks weighing 40–50 kg (88–110 lb). The eyes are small and deep-set and the ears long and broad. The species has well developed canine teeth, which protrude from the mouths of adult males. The medial hooves are larger and more elongated than the lateral ones and are capable of quick movements. The animal can run at a maximum speed of 40 km/h (25 mph) and jump at a height of 140–150 cm (55–59 in).
Sexual dimorphism is very pronounced in the species, with males being typically 5–10% larger and 20–30% heavier than females. Males also sport a mane running down the back, which is particularly apparent during autumn and winter. The canine teeth are also much more prominent in males and grow throughout life. The upper canines are relatively short and grow sideways early in life, though they gradually curve upwards. The lower canines are much sharper and longer, with the exposed parts measuring 10–12 cm (3.9–4.7 in) in length. In the breeding period, males develop a coating of subcutaneous tissue, which may be 2–3 cm (0.79–1.18 in) thick, extending from the shoulder blades to the rump, thus protecting vital organs during fights. Males sport a roughly egg-sized sack near the opening of the penis, which collects urine and emits a sharp odour. The function of this sack is not fully understood.
Adult size and weight is largely determined by environmental factors; boars living in arid areas with little productivity tend to attain smaller sizes than their counterparts inhabiting areas with abundant food and water. In most of Europe, males average 75–100 kg (165–220 lb) in weight, 75–80 cm (30–31 in) in shoulder height and 150 cm (59 in) in body length, whereas females average 60–80 kg (130–180 lb) in weight, 70 cm (28 in) in shoulder height and 140 cm (55 in) in body length. In Europe's Mediterranean regions, males may reach average weights as low as 50 kg (110 lb) and females 45 kg (99 lb), with shoulder heights of 63–65 cm (25–26 in). In the more productive areas of Eastern Europe, males average 110–130 kg (240–290 lb) in weight, 95 cm (37 in) in shoulder height and 160 cm (63 in) in body length, while females weigh 95 kg (209 lb), reach 85–90 cm (33–35 in) in shoulder height, and reach 145 cm (57 in) in body length. In Western and Central Europe, the largest males weigh 200 kg (440 lb) and females 120 kg (260 lb). In Northeastern Asia, large males can reach brown bear-like sizes, weighing 270 kg (600 lb) and measuring 110–118 cm (43–46 in) in shoulder height. Some adult males in Ussuriland and Manchuria have been recorded to weigh 300–350 kg (660–770 lb) and measure 125 cm (49 in) in shoulder height. Adults of this size are generally immune from wolf predation. Such giants are rare in modern times, due to past overhunting preventing animals from attaining their full growth.
The winter coat consists of long, coarse bristles underlaid with short brown downy fur. The length of these bristles varies along the body, with the shortest being around the face and limbs and the longest running along the back. These back bristles form the aforementioned mane prominent in males and stand erect when the animal is agitated. Colour is highly variable; specimens around Lake Balkhash are very lightly coloured, and can even be white, while some boars from Belarus and Ussuriland can be black. Some subspecies sport a light-coloured patch running backward from the corners of the mouth. Coat colour also varies with age, with piglets having light brown or rusty-brown fur with pale bands extending from the flanks and back.
The wild boar produces a number of different sounds which are divided into three categories:
Its sense of smell is very well developed to the point that the animal is used for drug detection in Germany. Its hearing is also acute, though its eyesight is comparatively weak, lacking color vision and being unable to recognise a standing human 10–15 metres (33–49 ft) away.
Pigs are one of four known mammalian taxa which possess mutations in the nicotinic acetylcholine receptor that protect against snake venom. Mongooses, honey badgers, hedgehogs, and pigs all have modifications to the receptor pocket which prevents the snake venom α-neurotoxin from binding. These represent four separate, independent mutations.
The main habitats favored by boars in Europe are deciduous and mixed forests, with the most favorable areas consisting of forest composed of oak and beech enclosing marshes and meadows. In the Białowieża Forest, the animal's primary habitat consists of well-developed broad-leaved and mixed forests, along with marshy mixed forests, with coniferous forests and undergrowths being of secondary importance. Forests made up entirely of oak groves and beeches are used only during the fruit-bearing season. This is in contrast to the Caucasian and Transcaucasian mountain areas, where boars will occupy such fruit-bearing forests year-round. In the mountainous areas of the Russian Far East, the species inhabits nutpine groves, hilly mixed forests where Mongolian oak and Korean pine are present, swampy mixed taiga and coastal oak forests. In Transbaikalia, boars are restricted to river valleys with nut pine and shrubs. Boars are regularly encountered in pistachio groves in winter in some areas of Tajikistan and Turkmenistan, while in spring they migrate to open deserts; boar have also colonized deserts in several areas they have been introduced to.
upy such fruit-bearing forests year-round. In the mountainous areas of the Russian Far East, the species inhabits nutpine groves, hilly mixed forests where Mongolian oak and Korean pine are present, swampy mixed taiga and coastal oak forests. In Transbaikalia, boars are restricted to river valleys with nut pine and shrubs. Boars are regularly encountered in pistachio groves in winter in some areas of Tajikistan and Turkmenistan, while in spring they migrate to open deserts; boar have also colonized deserts in several areas they have been introduced to.
On the islands of Komodo and Rinca, the boar mostly inhabits savanna or open monsoon forests, avoiding heavily forested areas unless pursued by humans. Wild boar are known to be competent swimmers, capable of covering long distances. In 2013, one boar was reported to have completed the 11-kilometre (7 mi) swim from France to Alderney in the Channel Islands. Due to concerns about disease, it was shot and incinerated.
Wild boar rest in shelters, which contain insulating material like spruce branches and dry hay. These resting places are occupied by whole families (though males lie separately) and are often located in the vicinity of streams, in swamp forests and in tall grass or shrub thickets. Boars never defecate in their shelters and will cover themselves with soil and pine needles when irritated by insects.
The species originally occurred in North Africa and much of Eurasia; from the British Isles to Korea and the Sunda Islands. The northern limit of its range extended from southern Scandinavia to southern Siberia and Japan. Within this range, it was only absent in extremely dry deserts and alpine zones. It was once found in North Africa along the Nile valley up to Khartoum and north of the Sahara. The species occurs on a few Ionian and Aegean Islands, sometimes swimming between islands. The reconstructed northern boundary of the animal's Asian range ran from Lake Ladoga (at 60°N) through the area of Novgorod and Moscow into the southern Urals, where it reached 52°N. From there, the boundary passed Ishim and farther east the Irtysh at 56°N. In the eastern Baraba steppe (near Novosibirsk) the boundary turned steep south, encircled the Altai Mountains and went again eastward including the Tannu-Ola Mountains and Lake Baikal. From here, the boundary went slightly north of the Amur River eastward to its lower reaches at the Sea of Okhotsk. On Sakhalin, there are only fossil reports of wild boar. The southern boundaries in Europe and Asia were almost invariably identical to the seashores of these continents. It is absent in the dry regions of Mongolia from 44 to 46°N southward, in China westward of Sichuan and in India north of the Himalayas. It is absent in the higher elevations of the Pamir and the Tian Shan, though they do occur in the Tarim basin and on the lower slopes of the Tien Shan.
In recent centuries, the range of wild boar has changed dramatically, largely due to hunting by humans and more recently because of captive wild boar escaping into the wild. Prior to the 20th century, boar populations had declined in numerous areas, with British populations probably becoming extinct during the 13th century. In the warm period after the ice age, wild boar lived in the southern parts of Sweden and Norway and north of Lake Ladoga in Karelia. It was previously thought that the species did not live in Finland during prehistory because no prehistoric wild boar bones had been found within the borders of the country. It was not until 2013, when a wild boar bone was found in Askola, that the species was found to have lived in Finland more than 8,000 years ago. It is believed, however, that man prevented its establishment by hunting. In Denmark, the last boar was shot at the beginning of the 19th century, and by 1900 they were absent in Tunisia and Sudan and large areas of Germany, Austria and Italy. In Russia, they were extirpated in wide areas by the 1930s. The last boar in Egypt reportedly died on 20 December 1912 in the Giza Zoo, with wild populations having disappeared by 1894–1902. Prince Kamal el Dine Hussein attempted to repopulate Wadi El Natrun with boars of Hungarian stock, but they were quickly exterminated by poachers.
A revival of boar populations began in the middle of the 20th century. By 1950, wild boar had once again reached their original northern boundary in many parts of their Asiatic range. By 1960, they reached Leningrad and Moscow and by 1975, they were to be found in Archangelsk and Astrakhan. In the 1970s they again occurred in Denmark and Sweden, where captive animals escaped and now survive in the wild. In England, wild boar populations re-established themselves in the 1990s, after escaping from specialist farms that had imported European stock.
The wild boar is a highly versatile omnivore, whose diversity in choice of food is comparable to that of humans. Their foods can be divided into four categories:
A 50 kg (110 lb) boar needs around 4,000–4,500 calories of food per day, though this required amount increases during winter and pregnancy, with the majority of its diet consisting of food items dug from the ground, like underground plant material and burrowing animals. Acorns and beechnuts are invariably its most important food items in temperate zones, as they are rich in the carbohydrates necessary for the buildup of fat reserves needed to survive lean periods. In Western Europe, underground plant material favoured by boars includes bracken, willow herb, bulbs, meadow herb roots and bulbs and the bulbs of cultivated crops. Such food is favoured in early spring and summer, but may also be eaten in autumn and winter during beechnut and acorn crop failures. Should regular wild foods become scarce, boars will eat tree bark and fungi, as well as visit cultivated potato and artichoke fields. Boar soil disturbance and foraging have been shown to facilitate invasive plants. Boars of the vittatus subspecies in Ujung Kulon National Park in Java differ from most other populations by their primarily frugivorous diet, which consists of 50 different fruit species, especially figs, thus making them important seed dispersers. The wild boar can consume numerous genera of poisonous plants without ill effect, including Aconitum, Anemone, Calla, Caltha, Ferula and Pteridium.
Boars may occasionally prey on small vertebrates like newborn deer fawns, leporids and galliform chicks. Boars inhabiting the Volga Delta and near some lakes and rivers of Kazakhstan have been recorded to feed extensively on fish like carp and Caspian roach. Boars in the former area will also feed on cormorant and heron chicks, bivalved molluscs, trapped muskrats and mice. There is at least one record of a boar killing and eating a bonnet macaque in southern India's Bandipur National Park, though this may have been a case of intraguild predation, brought on by interspecific competition for human handouts. There is also at least one recorded case of a group of wild boar attacking, killing, and eating an adult, healthy female axis deer (Axis axis ) as a pack.
Boars are typically social animals, living in female-dominated sounders consisting of barren sows and mothers with young led by an old matriarch. Male boars leave their sounder at the age of 8–15 months, while females either remain with their mothers or establish new territories nearby. Subadult males may live in loosely knit groups, while adult and elderly males tend to be solitary outside the breeding season.
The breeding period in most areas lasts from November to January, though most mating only lasts a month and a half. Prior to mating, the males develop their subcutaneous armour in preparation for confronting rivals. The testicles double in size and the glands secrete a foamy yellowish liquid. Once ready to reproduce, males travel long distances in search of a sounder of sows, eating little on the way. Once a sounder has been located, the male drives off all young animals and persistently chases the sows. At this point, the male fiercely fights potential rivals. A single male can mate with 5–10 sows. By the end of the rut, males are often badly mauled and have lost 20% of their body weight, with bite-induced injuries to the penis being common. The gestation period varies according to the age of the expecting mother. For first-time breeders, it lasts 114–130 days, while it lasts 133–140 days in older sows. Farrowing occurs between March and May, with litter sizes depending on the age and nutrition of the mother. The average litter consists of 4–6 piglets, with the maximum being 10–12. The piglets are whelped in a nest constructed from twigs, grasses and leaves. Should the mother die prematurely, the piglets are adopted by the other sows in the sounder.
Newborn piglets weigh around 600–1,000 grams, lacking underfur and bearing a single milk incisor and canine on each half of the jaw. There is intense competition between the piglets over the most milk-rich nipples, as the best-fed young grow faster and have stronger constitutions. The piglets do not leave the lair for their first week of life. Should the mother be absent, the piglets lie closely pressed to each other. By two weeks of age, the piglets begin accompanying their mother on her journeys. Should danger be detected, the piglets take cover or stand immobile, relying on their camouflage to keep them hidden. The neonatal coat fades after three months, with adult colouration being attained at eight months. Although the lactation period lasts 2.5–3.5 months, the piglets begin displaying adult feeding behaviours at the age of 2–3 weeks. The permanent dentition is fully formed by 1–2 years. With the exception of the canines in males, the teeth stop growing during the middle of the fourth year. The canines in old males continue to grow throughout their lives, curving strongly as they age. Sows attain sexual maturity at the age of one year, with males attaining it a year later. However, estrus usually first occurs after two years in sows, while males begin participating in the rut after 4–5 years, as they are not permitted to mate by the older males. The maximum lifespan in the wild is 10–14 years, though few specimens survive past 4–5 years. Boars in captivity have lived for 20 years.
Wild boars were apparently already becoming rare by the 11th century; a 1087 forestry law enacted by William the Conqueror punished through blinding the unlawful killing of a boar. Charles I attempted to reintroduce the species into the New Forest, though this population was exterminated during the Civil War. Between their medieval extinction and the 1980s, when wild boar farming began, only a handful of captive wild boar, imported from the continent, were present in Britain. Occasional escapes of wild boar from wildlife parks have occurred as early as the 1970s, but since the early 1990s significant populations have re-established themselves after escapes from farms, the number of which has increased as the demand for meat from the species has grown. A 1998 MAFF (now DEFRA) study on wild boar living wild in Britain confirmed the presence of two populations of wild boar living in Britain; one in Kent/East Sussex and another in Dorset.
Another DEFRA report, in February 2008, confirmed the existence of these two sites as 'established breeding areas' and identified a third in Gloucestershire/Herefordshire; in the Forest of Dean/Ross on Wye area. A 'new breeding population' was also identified in Devon. There is another significant population in Dumfries and Galloway. Populations estimates were as follows:
Population estimates for the Forest of Dean are disputed as, at the time that the DEFRA population estimate was 100, a photo of a boar sounder in the forest near Staunton with over 33 animals visible was published and at about the same time over 30 boar were seen in a field near the original escape location of Weston under Penyard many kilometres or miles away. In early 2010 the Forestry Commission embarked on a cull, with the aim of reducing the boar population from an estimated 150 animals to 100. By August it was stated that efforts were being made to reduce the population from 200 to 90, but that only 25 had been killed. The failure to meet cull targets was confirmed in February 2011.
Wild boars have crossed the River Wye into Monmouthshire, Wales. Iolo Williams, the BBC Wales wildlife expert, attempted to film Welsh boar in late 2012. Many other sightings, across the UK, have also been reported. The effects of wild boar on the U.K.'s woodlands were discussed with Ralph Harmer of the Forestry Commission on the BBC Radio's Farming Today radio programme in 2011. The programme prompted activist writer George Monbiot to propose a thorough population study, followed by the introduction of permit-controlled culling.
With the exception of domestic pigs in Timor and Papua New Guinea (which appear to be of Sulawesi warty pig stock), the wild boar is the ancestor of most pig breeds. Archaeological evidence suggests that pigs were domesticated from wild boar as early as 13,000–12,700 BCE in the Near East in the Tigris Basin, being managed in the wild in a way similar to the way they are managed by some modern New Guineans. Remains of pigs have been dated to earlier than 11,400 BCE in Cyprus. Those animals must have been introduced from the mainland, which suggests domestication in the adjacent mainland by then. There was also a separate domestication in China, which took place about 8,000 years ago.
DNA evidence from sub-fossil remains of teeth and jawbones of Neolithic pigs shows that the first domestic pigs in Europe had been brought from the Near East. This stimulated the domestication of local European wild boars, resulting in a third domestication event with the Near Eastern genes dying out in European pig stock. Modern domesticated pigs have involved complex exchanges, with European domesticated lines being exported in turn to the ancient Near East. Historical records indicate that Asian pigs were introduced into Europe during the 18th and early 19th centuries. Domestic pigs tend to have much more developed hindquarters than their wild boar ancestors, to the point where 70% of their body weight is concentrated in the posterior, which is the opposite of wild boar, where most of the muscles are concentrated on the head and shoulders.
