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Sus scrofa

(Bosnian Wild Boar)

Overview

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Mammal. Feral pigs are escaped or released domestic animals. Introduced to many parts of the world, they damage crops , stock and property and transmit many diseases. They dig up large areas of native vegetation and spread weeds , disrupting ecological processes such as succession and species composition.

Interesting Facts

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Common Names

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Click on the language to view common names.

Common Names in Dutch:

Wild zwijn of everzwijn

Common Names in English:

Bosnian Wild Boar, Central European Wild Pig, Eurasian Wild Boar, Eurasian Wild Pig, Feral Hog, Feral Pig, Old World Swine, pig, pig (feral), pigs, Razorback, Russian Wild Boar, Ryukyu Islands Wild Pig, swine, Wild Boar, Wild Hog

Common Names in French:

Sanglier, Sanglier D'Eurasie

Common Names in Russian:

Кабан

Common Names in Spanish:

Jabal?

Description

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Physical Description

Species Sus scrofa

Pigs are large omnivorous mammals with powerful bodies and coarse hairy coats . Their thick necks, wedge-shaped heads and mobile snouts enable them to root up the ground when feeding.

Habitat

Typically found at an altitude of 0 to 4,401 meters (0 to 14,439 feet).[1]

Ecology: The Eurasian wild pig occupies a wide variety of temperate and tropical habitats , from semi-desert to tropical rain forests , temperate woodlands, grasslands and reed jungles; often venturing onto agricultural land to forage . It is found in a variety of habitats. In Europe, it prefers broadleaved forests and especially evergreen oak forests, but may also be found in more open habitats such as steppe , Mediterranean shrubland, and farmland, so long as there is water and tree cover nearby (Spitz 1999). In Europe it is found from sea level to 2,400 in the Pyrenees (Palomo and Gisbert 2002), but it can be found at higher elevations in Asia.

The species is omnivorous , though stomach and fecal contents analyses indicate that vegetable matter, principally fruits, seeds, roots and tubers, constitutes about 90% of the diet (Spitz, 1986). A field study of the Indonesian wild pig, S. s. vittatus, in Ujung Kulon National Park in Java, indicated that these animals are predominately frugivorous , feeding on about 50 species of fruits, especially those of strangling figs (Ficus spp. ), and that they are important seed dispersal agents (Pauwels, 1980). By comparison, analyses of the stomach contents of wild pigs (also S. s. vittatus) in agricultural areas of West Malaysia by Diong (1973), revealed that sugar cane , tapioca and rice were the commonest food items, but that usually more than one type of food had been eaten, even where a single cultivated crop was abundant. Other items commonly consumed by these pigs included soil, earthworms, roots and other vegetable matter and, in mangrove areas, molluscs , crabs and other arthropods and even fishes . The consumption of invertebrate and small vertebrate prey may be a necessary component of the diet, since a study of free-ranging domestic pigs in Papua New Guinea revealed that animals fed ad libitum lost weight when denied earthworms (Rose and Williams, 1983). In common with its feral derivatives (Oliver and Brisbin, 1993), S. scrofa has also occasionally been reported to predate larger vertebrates, such as deer fawns and (tethered) goats (Hoogerwerf, 1970), though it is possible that such incidents involve only a few individuals in the population; an aspect also noted by Pauwels (1980) when referring to the predation of sea turtle nests by wild pigs in Ujung Kulon. Similarly, a large boar (S. s. cristatus) in Royal Chitawan National Park, Nepal, which was seen to displace an adult leopard from its kill, a domestic buffalo calf , which it then partly consumed (W. Oliver, pers. obs.), was reported by Park staff to regularly commandeer such kills, but that no other individual pigs had been seen to do this.

Wild pigs are normally most active in the early morning and late afternoon, though they become nocturnal in disturbed areas, where activity usually commences shortly before sunset and continues throughout the night. A total of 4 to 8 hours are spent foraging or traveling to feeding areas. Feeding is generally a social activity (even solitary males may join feeding groups) which also provides an opportunity for display and other agonistic behaviours (Beuerle, 1975). Radio telemetry studies in southern France indicate that they generally travel between 2 and 15 km per night, though this is often within an area of only 20 to 150 ha. However, the home range estimates for adult females and adult males over a 2-3 month period varied from 500-1,000 ha and 1,000-2,000 ha, respectively. During this same period, subadults covered an area of 500- 5,000 ha, and after 6 to 12 months they may have covered more than 10,000 ha; the larger home ranges of these animals being related to their expulsion from their natal groups and then undergoing a wandering phase . Movements over long distances (50 to 250 km) have also been recorded in Europe, but the extent and purpose of these movements has yet to be studied (Spitz, 1986). Experiments in which tagged animals are released and subsequently recovered provide evidence that they disperse freely over even larger areas (500 to 750 km), which may also indicate the area occupied by large population units. The density of free-ranging S. s. scrofa in Europe rarely exceeds 5 individuals/km (Spitz, 1986), though much higher concentrations have been reported elsewhere, e.g. 27-32/km on Peucang Island in Ujung Kulon National Park, Java (Pauwels, 1980) and 32.2-72.1/km in sugarcane areas in the Punjab, Pakistan (Shafi and Khokhar, 1985).

Wild pigs are gregarious , forming herds or 'sounders' of varying size depending on locality and season , but usually of between 6-20 individuals, though aggregations of over 100 have been reported (Prater, 1971; Legakul and McNeely, 1977; Briedermann, 1990)). The basic social unit is a nucleus of one or more females and their last litters . Animals peripheral to this comprise subadults from previous litters, and adult males during the mating season. However, the latter tend to stay in relatively close contact with 1 or 2 female groups at other times of the year, and subadult males or mixed sex groups of subadults may also form longer-term associations (Spitz and Janeau, 1990). The dynamics of the basic group include the isolation of the preparturient female, her re-entry with young, entry of nulliparous females, the arrival of adult males with the simultaneous departure of subadult animals (Spitz, 1986). In contrast to its domestic derivatives, reproductive activity in S. scrofa tends to be seasonal and positively correlated with the relative availability of principal foodstuffs or related climatic factors . In tropical countries, such as Sri Lanka, peak estrus activity has been recorded during the wettest months of November and December (Santiapillai and Chambers, 1980). However, social organization may also play a role in modulating the timing of reproductive events, since farrowing is often synchronized amongst females in the same social groups, which suggests a mechanism for synchronizing the onset of estrus (Spitz, 1986).

Wide fluctuations in the numbers of animals killed by hunters, particularly in the (former) U.S.S.R. and in France, suggest cyclic changes in the numbers of wild pigs available for hunting. Annual recruitment into the total population depends on reproductive rate (i.e. the number and prolificacy of females) and juvenile mortality , both of which factors may be influenced by the availability of foodstuffs and other external factors (Spitz, 1986). In western Europe, litter size is usually between 4 and 7 piglets (Briedermann, 199), though Harrison and Bates (1991) cite reports of 5 and 7-10 piglets per litter as being usual in Iraq and Armenia, respectively. Pauwels (1980) recorded an average litter size of 6-10 piglets at the beginning of the breeding season in Java, but this number dropped to only 2-4 piglets per litter towards the end of the breeding season. In the Ryukyu Islands, S. Japan, there is evidence that the wild pigs (S. s. riukiuanus) have two breeding seasons per year, though it remains uncertain whether individual sows normally produce litters twice a year (Yasuma, 1984). Juvenile mortality averages 15% in the first three months in western Europe, though between 50% and 75% mortality have been reported by the end of the first year of life (Jezierski, 1977; Briedermann, 1990). These mortality rates are thought to be highly dependant on such external factors as predation and climatic hazards, at least in wilderness areas (Spitz, 1986). Similarly, Pauwel (1982) suggested that the principal causes of juvenile mortality in wild pigs in Ujung Kulon were predation (particularly as a consequence of the accidental separation of infants from their mothers), along with differences in the relative rate of development of litter-mates and various parasite-related causes. These factors resulted in only about 15% of all progeny surviving to independence .[2].

List of Habitats:

Biology

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Diet

A Wild Pig will eat almost anything that has nutritional value, including tubers, roots , shoots , acorns , fruits, berries , earthworms, amphibians , reptiles , rodents, and even newborn fawns of the White-tailed Deer.

Reproduction

Feral pigs are polyoestrus: adult females have a 21-day oestrus cycle and a gestation period of about 112-114 days. In New Zealand they probably breed throughout the year, though mainly in spring and summer (Wodzicki 1950; J. McIlroy unpublished.).In New Zealand pigs breed throughout the year, with a litter size of 6-10 piglets, but usually only half this number survive. They reach breeding age at between 10 and 12 months (Wodzicki 1950).

Pigs are normally social animals but adult boars over 18 months old are invariably solitary (McIlroy 1990).

Behavior

Humans are the major predators of this species, but large carnivores like the Black Bear and the Mountain Lion are capable of preying on young adults . Piglets may be preyed upon by bobcats, foxes, and coyotes. During the summer months, Wild Pigs create wallows in wet sites.

Taxonomy

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Synonyms

Sus andamanensis • Sus aruensis • Sus babi • Sus ceramensis • Sus enganus • Sus floresianus • Sus goramensis • Sus natunensis • Sus nicobaricus • Sus niger • Sus papuensis • Sus ternatensis • Sus tuancus

Notes

Name Status: Accepted Name .

Last scrutiny: 22-Apr-2004

In a major review of the Genus Sus, Groves (1981) recognized 16, possibly 17, subspecies , whilst also either synonymizing or discounting many previously accepted subspecies. The latter including various insular southeast Asian feral and/or hybrid populations. This treatment was followed by Groves and Grubb (1993); though Groves (2001) has since suggested the likely future separation of one subspecies, i.e. the Banded Pig S. s. vittatus, as a full species (Groves, 2001).[2].

Similar Species

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The only native North American wild pig, the Collared Peccary Tayassu tajacu inhabits the deserts and thorn scrub of Arizona, New Mexico, and south Texas.

Members of the genus Sus

ZipcodeZoo has pages for 18 species and subspecies in this genus:

S. ahoenobarbus (Palawan Bearded Pig) · S. barbatus (Western Bearded Pig) · S. barbatus ahoenobarbus (Palawan Bearded Pig) · S. barbatus oi (Western Bearded Pig) · S. bucculentus (Indo-Chinese Warty Pig) · S. cebifrons (Visasyas Warty Pig) · S. cebifrons cebifrons (Cebu Warty Pig) · S. celebensis (Sulawesi Warty Pig) · S. cristatus (Bornean Pig) · S. heureni (Flores Warty Pig) · S. oliveri (Oliver's Warty Pig) · S. philippensis (Philippine Warty Pig) · S. salvanius (Pigmy Hog) · S. scrofa (Bosnian Wild Boar) · S. scrofa domesticus (Pig) · S. scrofa riukiuanus (Ryukyu Islands Wild Pig) · S. timoriensis (Timor Warty Pig) · S. verrucosus (Javan Warty Pig)

More Info

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Further Reading

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Notes

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Contributors

Data Sources

Accessed through GBIF Data Portal November 12, 2007:

Identifiers

Footnotes

  1. Mean = 128.250 meters (420.768 feet), Standard Deviation = 416.480 based on 171,993 observations. Altitude information for each observation from British Oceanographic Data Centre. [back]
  2. Oliver, W. & Leus, K. 2008. Sus scrofa. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 05 February 2012. [back]
Last Revised: 4/17/2012