Common warthog  (Phacochoerus africanus)

Classified as Least Concern (LC) on the IUCN Red List (1).

One of the most distinctive of all wild pigs, the common warthog is named for the two prominent pairs of large, fleshy protuberances that project from the male’s head (2) (3). This species possesses relatively long legs for a pig, which support a barrel-shaped body, sparsely covered with dark-brown to blackish hair. The large head is broad at the rear, tapering towards the snout, with two upwardly curved upper tusks, measuring 26 to 64 cm in the male and 15 to 26 cm in the female, projecting from the mouth, along with two shorter, sharper lower tusks (2). A white fringe of hair runs along a ridge-like fold of skin on the cheek, while a long dark mane extends from the nape of the neck to the middle of the back, where there is a gap, before continuing to the rump. A characteristic feature of the common warthog is that when running, the tail is held straight and upright (4). This species is highly vocal, producing a range of grunts, growls, snorts and squeals, which serve functions such as greetings, maintaining contact and threat displays (2).

The common warthog has a large range, extending across much of sub-Saharan Africa, with scattered populations occurring from West Africa, east to Ethiopia and south as far as northern South Africa (1). Four subspecies are recognised: Phacochoerus africanus africanus, which occurs from Sahel to central Ethiopia; Phacochoerus africanus aeliani, which inhabits northern Ethiopia and Djibouti; Phacochoerus africanus massaicus, which occupies eastern and central Africa; and Phacochoerus africanus sundevallii, which is found in thenorthern part of the southern African sub-region (3)

The common warthog is found in open habitats, such as moist and dry African savanna, open bushlands and woodlands, although in the Goda Mountains in Djibouti it is known to occur in forest (1) (2). It can be found from sea-level to elevations of up to 3,500 metres in the Ethiopian Highlands (1)

The common warthog has three distinct types of social unit, comprising solitary adult males; bachelor groups of younger males; and groups of 4 to 16 females and their mixed-sex offspring (2) (4). Unlike other pigs, the common warthog is predominantly a grazer and feeds on the growing tips of grasses, although it will also take roots, berries, the bark of young trees and occasionally carrion (2) (4). When grazing, the common warthog folds its front feet under to bring its head to the tips of the grass and rests on its padded ‘wrists’. In contrast, when rooting up plants during the dry season, it uses its toughened snout to shovel soil aside (2) (4). At night, the common warthog usually rests in a naturally occurring burrow or one that has been excavated by an aardvark, although where it is disturbed by human activity, its activity pattern may shift so that some foraging takes place at night (2). The common warthog is not territorial, and several groups may co-habit the same area, sharing burrows and resources, although some competition may occur when food and water are scarce (2) This species is not aggressive unless cornered, when it will use its sharp lower tusks in defence (2). The common warthog is mainly preyed upon by lions and leopards (3).

The common warthog generally breeds seasonally, with mating occurring between May and June in Zimbabwe, though populations around the equator may breed throughout the year (2) (3). When seeking a mate, adult males briefly join the female groups, and may compete with other males in ritualised battles. These involve striking and pushing with the upper tusks, but due to the protection afforded by the facial warts, rarely result in injury (2). After a gestation period of 150 to 175 days, a litter of between one and eight, though usually two or three, offspring is born. The piglets are initially sheltered in a grass-lined burrow, but when ready to leave this refuge, accompany the mother closely (2) (4). The piglets are weaned at 21 weeks, but remain in association with the mother for an extended period. The males usually leave the mother when aged around 15 months, whereas the females either leave when older, or remain in the same group for life. Sexual maturity is reached at 18 to 20 months, and maximum lifespan has been recorded at over 18 years in captivity (2)

As a whole, the population of the common warthog is abundant and not undergoing a significant decline (1). Nevertheless, this species is widely hunted and persecuted for crop damage, and has therefore been extirpated from some regions. The status of the subspecies Phacochoerus africanus aeliani is a cause for concern, as its population is very low and susceptible to overexploitation (2).

While there are currently no known conservation measures specifically targeting the common warthog, it is present in numerous protected areas across its extensive range (1). Outside protected areas, in order to control the decline this species, trade in bushmeat and ivory must be monitored. In addition, research into the threatened subspecies Phacochoerus africanus aeliani is urgently required so that management plans and a captive breeding program can be implemented (3).

View information on this species at the UNEP World Conservation Monitoring Centre.

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Glossary

• Bushmeat: the meat derived from wildlife of African forests, or ‘bush’.
• Carrion: the flesh of a dead animal.
• Gestation: the state of being pregnant; the period from conception to birth.
• Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
• Territorial: an animal, a pair of animals or a colony that occupies and defends an area.

References

1. IUCN Red List (August, 2009)
   www.iucnredlist.org/
2. Nowak, R.M. (1999) Walker's Mammals of the World. Johns Hopkins University Press, Baltimore, Maryland.
3. Oliver, W.L.R. (1993) Pigs, Peccaries, and Hippos Status Survey and Conservation Action Plan. IUCN, Gland, Switzerland. Available at:
   data.iucn.org/dbtw-wpd/edocs/1993-055.pdf
4. Burnie, D. (2001) Animal. Dorling Kindersley, London.