Phacochoerus africanus (Gmelin, 1788)

Don E. Wilson & Russell A. Mittermeier, 2011, Suidae, Handbook of the Mammals of the World – Volume 2 Hoofed Mammals, Barcelona: Lynx Edicions, pp. 248-291 : 276-277

4.

Common Warthog

Phacochoerus africanus

French: Phacochere d'Afrique / German: \Warzenschwein / Spanish: Facocero de sabana

Taxonomy. Sus africanus Gmelin, 1788 ,

“Habitat in Africa a capite viridi as caput bonae spei”; restricted to Senegal, “ Cape Verd [ Verde ].”

Four subspecies are recognized.

Subspecies and Distribution.

P. a. africanusGmelin, 1788 — NsavannaandSahelregion, fromMauritaniatoEthiopia. Pa. aelianiCretzschmar, 1828 — Eritrea, Djibouti, andNSomalia.

P. a. massaicusLonnberg, 1908 — E & CAfrica, fromNUgandaandSKenya, E & SDRCongo, Rwanda, Burundi, Tanzania, Zambia, Malawi, andNMozambique.

P. a. sundevallii L.onnberg, 1908 — S Africa, including SW Angola, N & E Namibia, N Botswana, Zimbabwe, S Mozambique, and parts of South Africa.

Descriptive notes. Head-body 125-150 cm (males), 105-140 cm (females), tail 35-50 cm), shoulder height 55-85 cm; weight 60-150 kg (males), 50-75 kg (females). Thisis a pig with long legs and short neck. Proportionally it has a massive head with broad and flattened muzzle and snout, and prominent curved tusks flaring upwards. The upper tusks measure an average 25-30 cm in length in adult males (record 60 cm) whereas the lower tusks are only 13 cm. The grayish body is barrel shaped, with a hairless skin that can take on differing hues of gray or brown depending on the color of the soil in its holes or wallows. A dorsal mane of yellowish to jet black hairsis longest on the shoulders and neck. A narrow, tufted tail is held vertically when trotting. In many individuals, whitish bristles on the lower jaw form conspicuous “sideburns.” Three pairs of facial warts of different shape and thickness, made of fibrous tissue, are situated on the muzzle, along the jaw, and under the eyes. In males, the infraocular warts can grow up to 15 cm and have a protective function. They can take on various orientations, but are always conical; only the Desert Warthog (PF. aethiopicus ) displays curled down jugal warts. Warts are less developed in females, as are the tusks and preorbital glands. Common Warthogs usually trot in a quick, springy stride, with the head held high and the back rigid. When grazing or rooting, they often drop on their “knees” instead ofstretching their short neck. Callosities characteristic of carpal joints on the forelegs are observed on embryos. These observations support evolutionary theories of “anticipatory” adaptation or of the heredity of acquired characters. Females have four pairs of mammae. Dental formulaisI1/3,C1/1,P3/2,M 3/3 (x2) = 34. Whereas the Desert Warthog is characterized by an absence of functional incisors, Common Warthogs always have two upper incisors and usually six functional lower incisors as in the adult dentition of most pigs.

Habitat. Common Warthogs are the only African pigs that are typical open-country species, with morphological and behavioral adaptations typical of grazers. Generally they are confined to various types of savanna grasslands, open bushlands, and woodlands, usually within range of perennial surface water. Although usually absent from forests, thickets, cool montane grasslands, deserts, and steppes, Common Warthogs are present in aridlands near the Danakil desert and Bale Mountain forests ( Ethiopia) and in Djibouti forests. Abundance of Common Warthogs is probably linked to the availability of Aardvark (Orycteropus afer) holes, as the warthogs need deep burrows for protection from predators as well as from fluctuations in temperature and humidity. Their bodies can obviously sustain a certain tolerance range, and they cope with high temperature by sheltering in shade, wallowing, and dust-bathing. Piglets are particularly vulnerable to cold and malnutrition during drought, which, together with predation and other factors, account for an over 50% mortality rate during the first year.

Food and Feeding. Common Warthogs have an omnivorous diet composed of grasses, roots, fruits, bark, fungi, eggs, and carrion, as well as small mammals, reptiles, and birds. The diet varies with seasonal availability of food items, although the species is very selective. Areas with abundant food resources like bulbs, rhizomes, and nutritious roots can sustain large temporary congregations of animals. This opportunism and dietary versatility account for the Common Warthog’s successful survival strategy. They are powerful diggers, using both snout and hooves, but not tusks. When feeding, they often walk on their anterior knuckles with their hindquarters raised. They use their incisors to wrench grass stems or strip seedheads, and they excavate rhizomes and mineral-rich earth with the hard edge of their snout.

Breeding. Both sexes reach puberty at 18 months. During the rut, boars locate estrous females by visiting burrows. Male fights consist of frontal-pushing, interlocking tusks, and hitting the opponent in the face or in the flanks. The mating system is promiscuous, with males roaming and mating with numerous females and females mating with more than one male. Where seasons are marked, breeding is seasonal, with females usually coming into estrus early in the dry season and farrowing at the beginning of the rainy season. Non-offspring nursing occurs. Gestation is 160-170 days and most common litter size is 2-3 (range: 1-8).

Activity patterns. Common Warthogs are highly diurnal. They go underground before dark and sleep in abandoned burrows of Aardvarks or other animals. Males enterlast and commonly reverse in, with the head facing the opening, ready to fight an intruder or rush out as needed. To a certain extent, season and weather dictate their daytime activity, which includes a range of typical occupations like feeding, drinking, wallowing, rubbing against trees or termite mounds, and grooming. Feeding occurs mainly in early morning and late afternoon, but they also graze between irregular resting periods in the shade of bushy thickets or in mud wallows. Humans, Lions (Panthera leo), Leopards (P. pardus), crocodiles, and hyenas are the main predators, but Cheetahs (Acinonyx jubatus) and African Wild Dogs (Lycaon pictus) are also capable of catching small warthogs. Females are extremely aggressive and courageous when defending their piglets. It has been reported that Common Warthogs have inflicted deep and deadly wounds in Lions. Common Warthogs have been observed allowing Banded Mongooses (Mungos mungo) and ground hornbills (Bucorvus spp.) to groom them to remove ticks.

Movements, Home range and Social organization. On average, sounders move a distance of 7 km /day, and visit the same areas at about the same time. Their home range averages 174 ha (range: 64-374 ha) and both males and females tend to remain close to their natal area. Typical densities are 1-10 ind/km?® in protected areas, but local densities of up to 77 ind/km? were found on short grass in Lake Nakuru National Park, Kenya. The social structure of Common Warthogs is one of small groups: solitary males or bachelor groups (45% of the population), matriarchal groups consisting of adult females with juveniles and/or yearlings, or yearling groups. Boars accompany sounders when females are in estrus. Females are temporarily on their own at farrowing time, but they commonly join up with other females and their young. Bonds between adult females and between mothers and daughters can be stable and last over several breeding cycles.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Common Warthogs occur in most protected areas in savanna zones. Expansion of the Sahel has resulted in a contraction of its range in the north and accounts forits decline in Mauritania and Niger. Because of their susceptibility to drought and predation, populations may easily be prone to local extinction. In the past, populations were greatly reduced by rinderpest in some countries.

Bibliography. Child et al. (1968), Clough & Hassam (1970), Cumming (1975, 2008, In Press), Deribe et al. (2008), Estes (1991), Grubb (1993), Kingdon (1997), Kunzel et al. (2004), Muwanika et al. (2007), Radke (1991), Somers (1997), Somers et al. (1995), Treydte, Bernasconi et al. (2006), Treydte, Halsdorf et al. (2006), Vercammen & Mason (1993).

Figures

On following pages 2 Moluccan Babırusa (Babyrousa babyrussa) 3 Tog an Babırusa (Babyrousa rogeanensıs) 4 Common Warthog (Phacochoorus alncanus) 5 Desert Warthog (Phacochoerus aethıopıcus) 6 Forest Hog (Hylochoerus maınenzhagenı) Bushpıg (Pommochoeıus Iarvalusl 8 Red Rıver Hog (Poramochoerus porcas)

Subspecies and Distribution. P. a. africanusGmelin, 1788 — NsavannaandSahelregion, fromMauritaniatoEthiopia. Pa. aelianiCretzschmar, 1828 — Eritrea, Djibouti, andNSomalia. P. a. massaicusLonnberg, 1908 — E & CAfrica, fromNUgandaandSKenya, E & SDRCongo, Rwanda, Burundi, Tanzania, Zambia, Malawi, andNMozambique. P. a. sundevallii L.onnberg, 1908 — S Africa, including SW Angola , N & E Namibia , N Botswana , Zimbabwe , S Mozambique , and parts of South Africa .