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)