Hylochoerus meinertzhageni
giant forest hog

Forest hogs are found in Africa, mainly in the equatorial forests and grasslands west, west of the Rift Valley. There are a few scattered small populations northeast of Lake Victoria, and several scattered larger populations from Nigeria to Senegal. There are three recognized subspecies, each with distinct ranges. The forest hog H. m. ivoriensis inhabits the area near the Ivory Coast, H. m. rimator lives in two areas near the west and central equatorial zone and coexists in the east equatorial zone with H. m. mienertzhagheni, the "true" giant forest hog. A potential fourth subspecies exists to the north of H. m. mienertzhagheni. (d'Huart, 1993; Estes, 1991)

The giant forest hog prefers the dense shade of thickets and bushes. This suid ranges through a variety of forest types, including dry forests; humid, lowland forests; and montane forests (up to 3,800 m). H. meinertzhageni is most common near permanent water sources, especially where there is a thick understory cover. However, it does venture out into clearings and grasslands to feed. (d'Huart, 1993; Estes, 1991)

Standing approximately 1m high and 190 cm long, Hylochoerus meinertzhageni adults have a huge broad head, and males have pads of naked, inflated skin near their eyes. Both sexes have small, straight tusks that flare outward (to 30 cm) and teeth modified for grazing and browsing. The giant forest hog has large, pointed ears and bristly hair on its body and tail. Color is slate gray with some lighter hair on the face. The male's cheek pads contain scent glands, and this hog also has a preputial scent gland. Females are slightly smaller than males and have 4 mammae. (Estes, 1991; Walker, 1968)

Forest hogs are shy creatures that live in low population densities and are therefore not well known. They are nocturnal and live in groups called 'sounders' which consist of 6-14 individuals in a 1:2 male:female ratio, led by a male. Subadult males form bachelor groups. The hogs tend to be more active, up to 10 hours per day, in areas where they are not hunted, and will range 8-12 km per day. They are most often out in the open during up to four hours of steady feeding between dusk and midnight. A range will consist of pastures, sleeping areas, water holes, wallows, rubbing places, latrines, and mineral licks, connected by paths through the underbrush. These suids scrape dirt from beneath logs or roots to bed down. Boars are intolerant of others, and will engage in one of two forms of fighting: snout pushing, a test of weight, or forehead ramming, which often fractures the skull. If cranial hollows meet exactly, this ramming behavior produces a loud report. A mating pair of hogs will leave a sounder, the male grunting loudly, and urinating frequently. The boar butts the female's hindquarters until she stands for copulation, which may last 10 minutes. Adults will surround piglets to defend them from their main predator, the hyena, and the leopard, which hunts them as well. Piglets will freeze at the sound of an alarm grunt. Forest hogs are extremely susceptible to hunting, because they come to bay and fight at the edge of cover (Estes 1991, d'Huart 1993).

Herbivore: The forest hog is unable to root like other Suidae, but it can dig quite well with its tusks for roots and minerals. Otherwise, the forest hog grazes on grasses, sedges and herbage. Sometimes, these suids will ingest carrion or eggs. They also practice coprophagy (Estes 1991, d'Huart 1993).

The forest hog is a symptomless carrier of African Swine Fever (ASF), which is lethal to domestic pigs. This disease is transmitted by a tick called the tampan. These suids also can carry the trypanosomes for sleeping sickness (ngana) that is transmitted by the tse-tse fly to livestock and humans. They also transmit rinderpest and are responsible for significant crop damage (Macdonald 1995, d'Huart 1993).

The forest hog is an easy target for hunting, and although among some peoples of the Congo, the eating of H. mienertzhageni is considered to cause calamity, the species is hunted in much of its range, not only for subsistence, but for commercial meat markets. There is also some trade for the ivory of its tusks, and hides were sometimes used for leather. (d'Huart, 1993; Walker, 1968)

The forest hog is rated 3-4 by IUCN. This means that it has a restricted distribution, is threatened by habitat destruction, hunting pressure or other ecological pressure, however populations are not declining. The subspecies Hylochoerus mienertzhagheni mienertzhagheni has the smallest range, but appears to be relatively secure (Oliver 1993).